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NTA Level 5 • Semester 1 • PST05106 Amines of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 21 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 21: Amines of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites None Learning Tasks By the end of this session students are expected to be able to: • Define Amines • Explain nomenclature of amines • Draw chemical structure of amines • List chemical properties of amines • Explain chemical reactions of amines Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Amines | | | |Presentation | | |3 |15 minutes |Presentation |Nomenclature of Amines | |4 |15 minutes |Presentation |Chemical Structure of Amines | |5 |20 minutes |Buzzing |Chemical Properties of Amines | | | |Presentation | | |6 |45 minutes |Group |Chemical Reactions involving Amines | | | |discussion | | | | |Presentation | | |7 |05 minutes |Presentation |Key Points | |8 |05 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Amines (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Amines? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | • Amines are organic derivatives of ammonia NH3 with one or more alkyl or aryl groups bonded to the nitrogen atom. • Amines contain a nitrogen atom with a lone pair of electrons; basic & nucleophilic. • Amines are present widely throughout both plants & animals. • As a class amine include some of the most important biological compounds. • Amines serve many functions in living organisms such as bioregulation, neurotransmission, and defense against predators. Examples of some biologically active amines [pic] [pic] [pic] [pic] [pic] STEP 3: Nomenclature of Amines (15 minutes). • The IUPAC nomenclature for amines is similar to that for alcohols. • The longest continuous chain of the carbon atoms determines the root name. • The -e ending in the alkane name is changed to -amine, and a number shows the position of the amino group along the chain. • Other substituents on the carbon chain are given numbers, and the prefix N- is used for each substituent on nitrogen. Examples [pic] Common Names • Common names of amines are formed from the names of the alkyl groups bonded to nitrogen, followed by the suffix –amine • The pefixes di-, tri and tetra- are used to describe two, three, or four identical substituents Examples [pic] [pic] • In naming amines with more complicated structures, the -NH2 group is called the amino group. • The amino group is treated like any other substituent, with a number or other symbol indicating its position on the ring or carbon chain. Examples [pic] [pic] • Aromatic and heterocyclic amines are generally known by historical names. • For example, phenylamine is called aniline, and its derivatives are named as derivatives of aniline. [pic] [pic] Heterocyclic amines • Compounds in which the nitrogen atom occurs as part of a ring. • The heterocyclic nitrogen atom is always numbered as position 1. Examples [pic] STEP 4: Chemical Structure of Amines (15 minutes). • The basic chemical structure is that of ammonia (NH3) with the key atom being the central nitrogen atom. • The basic ammonia structure is changed when the hydrogen atoms are replaced by alkyl groups to form amines. • There are primary, secondary and tertiary amines. |[pic] | | |Secondary amine | | | | | | [pic] Primary amine [pic] Tertiary amine • The naming of amines is pretty straightforward. Primary amines are called things like methylamine (CH3-NH2) and ethylamine (CH3-CH2-NH2). • Simple secondary and tertiary amines are also easy to name. Dimethylamine is CH3-NH-CH3 and trimethylamine is CH3-N(CH3)-CH3. • Larger amines have names beginning with amino. For example, CH3-CH(NH) -CH2-CH2-CH3 is called 2-aminopentane. STEP 5: Chemical Properties of Amines (15 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | | | |What are the chemical properties of Amines? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response on the flip chart/board. | | | |CLARIFY and SUMMARIZE by using the content below | • They react with acids to form acid-base salts • They react with electrophiles in polar reactions • Amines are stronger bases than alcohols, ethers or water • Kb (basicity constant) – used to measure the base strength of an amine • Simple methylated amines are prepared by reaction of NH3 with CH3OH in the presence of alumina catalyst. STEP 6: Chemical Reactions involving Amines (45 minutes) |Activity: Small Group Discussion (20 minutes) | | | |DIVIDE students into small groups | | | |ASK students to discuss in groups on the following questions | |What are the chemical reactions involving Amines? | | | |[pic]REFER Students to Book | | | |ALLOW students to discuss for 15 minutes | | | |ALLOW each group to present for 5 minutes | | | |CLARIFY and SUMMARIZE by using the contents below | Due to the unshared electron pair, amines can act as both bases and nucleophiles. • Reaction with acids When reacted with acids, amines donate electrons to form ammonium salts. [pic] • Reaction with acid halides o Acid halides react with amines to form substituted amides. [pic] o Aldehydes

NTA Level 5 • Semester 1 • PST05106 Aryl Halides of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 20 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 20: Aryl Halides of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites None Learning Tasks By the end of this session students are expected to be able to: • Define aryl halides • Explain nomenclature of aryl halides • Draw chemical structure of aryl halides • List chemical properties of aryl halides • Explain chemical reactions of aryl halides Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Aryl Halides | | | |Presentation | | |3 |15 minutes |Presentation |Nomenclature of Aryl Halides | |4 |15 minutes |Presentation |Chemical Structure of Aryl Halides | |5 |20 minutes |Buzzing |Chemical Properties of Aryl Halides | | | |Presentation | | |6 |45 minutes |Group |Chemical Reactions involving Aryl | | | |discussion |Halides | | | |Presentation | | |7 |05 minutes |Presentation |Key Points | |8 |05 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes). READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Aryl Halides (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Phenols? | | | |ALLOW few students to respond. | | | |WRITE their responses on the flip chart/ board. | | | |CLARIFY and SUMMARISE by using the content below | Aryl halides are the compounds that contain halogen atom directly attached to the benzene ring. They have general formula ArX. [pic] Any halogen compound that contains a benzene ring is not classified as aryl halide. e.g. Benzyl chloride is not an aryl halide but is a substituted alkyl halide. STEP 3: Nomenclature of Aryl Halides (15 minutes). • Functional group suffix = -halobenzene Functional group prefix = halo- Numbering of the ring begins at the halogen-substituted carbon and proceeds in the direction of the next substituted carbon that possesses the lower number. • Mono-substituted aryl halides are characterized using the prefix ortho (o- ), meta (m-) or para (p-) depending on the placement of the substituent from the halogen or the halogen from a higher priority functional group: 1,2-, 1,3- or 1,4- respectively. | | | | |1-chloro-2-ethylbenze|1-chloro-3-ethylbenze|1-chloro-4-ethylbenze| |ne |ne |ne | |or |or |or | |o-ethylchlorobenzene |m-ethylchlorobenzene |p-ethylchlorobenzene | STEP 4: Chemical Structure of Aryl Halides (15 minutes). • An aryl halide is classified by its distinct bonding of a halogen directly to a benzene ring. o From a structural standpoint, one of the more important things to realize is the trend in bond lengths of the four aryl halides. • Since the trend for atomic size goes F < Cl < Br < I, (meaning fluorine is smaller than chlorine, which is smaller than bromine, etc.) it's probably not surprising that in terms of bond length, the observation is as follows: |[pic] | |Bond lengths (given in picometers) of the four | |aryl halides | • The bond lengths here are measured in picometers, which is a small unit of measurement used because we are talking about chemical bonds on a microscopic scale. • Notice that as we go from fluorine, to chlorine, to bromine, to iodine, the bond lengths get longer and longer. • That is because as the size of the halogen gets bigger, the bond has to elongate to make room for the larger atom that's bonded to the benzene ring. STEP 5: Chemical Properties of Aryl Halides (20 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | | | |What are the chemical properties of Aryl Halides? | | | |ALLOW pairs to respond on the question | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content below | Reactivity of Aryl halides • In haloalkane, the carbon atom attached to halogen is sp3 hybridised while in case of haloarene, the carbon atom attached to halogen is sp2- hybridised. [pic] • The sp2 hybridized carbon with a greater s-character is more electronegative and can hold the electron pair of C—X bond more tightly than sp3 -hybridized carbon in haloalkane with less s- character. • Thus, C—X bond length in halo alkane is shorter than those present in haloarene. • Since it is difficult to break a shorter bond than a longer bond, therefore, haloarenes are less reactive than haloalkanes towards nucleophilic substitution reaction. • Unlike alkyl halides, aryl halides are less reactive towards Nucleophilic substitution reactions, this can be attributed to their electron release via resonance [pic] • Structures III, IV and V stabilise chlorobenzene molecule and give a double bond character to the carbon-chlorine bond. • Now because of this the carbon-chlorine bond has more strength and hence aryl halides are more stable towards Nucleophilic substitution reactions. • In Alkyl halides the carbon atom attached to halogen is sp3 hybridized and in aryl halides it is sp2, hybridized, as sp2 hybridized carbon is more electronegative it does not permit the chlorine atom to get displaced with the bonded pair of electrons. Nucleophilic Substitution Reactions of Aryl Halides • Aryl halides undergo Nucleophilic substitution reactions when a strong Electron withdrawing group is present on the benzene ring. • Electron withdrawing groups activate the benzene ring towards nucleophilic substitution in aryl halides whereas Electron donating groups deactivate the ring. Elimination – Addition Mechanism • In the absence of an electron withdrawing group, nucleophilic substitution

NTA Level 5 • Semester 1 • PST05106 Phenols of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 19 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 19: Phenols of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define phenols • List phenols and their isomers • Explain nomenclature of phenols • Draw chemical structure of phenols • List chemical properties of phenols • Explain chemical reactions of phenols Resources Needed: • Flip charts, marker pens, and masking tape. • Black/white board and chalk/whiteboard markers. SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Presentation |Definition of Phenols | | | |Brainstorming | | |3 |15 minutes |Presentation |Phenols and their Isomers | |4 |15 minutes |Presentation |Nomenclature of Phenols | |5 |15 minutes |Presentation |Chemical Structure of Phenols | |6 |15 minutes |Presentation |Chemical Properties of Phenols | | | |Buzzing | | |7 |35 minutes |Presentation |Chemical Reactions involving Phenols| | | |Group | | | | |discussion | | |8 |05 minutes |Presentation |Key Points | |9 |05 minutes |Presentation |Evaluation | SESSION CONTENTS. STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Phenols (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Phenols? | | | |ALLOW few students to respond. | | | |WRITE their responses on the flip chart/ board. | | | |CLARIFY and SUMMARISE by using the content below | • Phenols are organic compounds which contain a hydroxyl (—OH) group attached to a carbon atom in a benzene ring. • Their chemical behaviour is very distinct from that of alcohols, because they are not capable of undergoing the same oxidation reactions that alcohols participate it. • Also, unlike alcohols, phenols are weak acids, since the phenoxide anion generated by the loss of the hydroxyl proton is resonance-stabilized: [pic] [pic] • Phenol is the active ingredient in some treatments for sore throats and is found in several lozenges and throat sprays. • It is used in the manufacture of many other compounds, such as aspirin, and Bakelite. STEP 3: Phenols and their Isomers (10 minutes). • Cresol is a trivial name for the three isomeric methylphenols. ortho-Cresol [pic] • The structure shown above is ortho-cresol, or 2-methylphenol; the other isomers are shown below. 2,6 xylenol [pic] • The cresols are commonly used as solvents, in disinfectants and deodorizers, and in the manufacture of other compounds (for example, the BHA and BHT shown below). • Xylenol is a trivial name given to the six isomeric dimethylphenols. • The name is derived from xylene, which is the trivial name for the three isomeric dimethylbenzenes. • The structure shown above is 2,6-xylenol, or 2,6-dimethylphenol; the other isomers are shown below. [pic] • The xylenols are found in a number of pesticides and are also used in the manufacture of many other compounds. STEP 4: Nomenclature of Phenols (15 minutes). • Locate the position of hydroxyl group attached to the benzene ring. • Benzene rings attached to more than one hydroxyl groups are labeled with the Greek numerical prefixes such as di, tri, tetra to denote the number of similar hydroxyl groups attached to the benzene ring. • If two hydroxyl groups are attached to the adjacent carbon atoms of benzene ring, it is named as benzene1, 2-diol • In case of substituted phenols, we start locating the positions of the other function groups with respect to the position where the hydroxyl group is attached. For example, if a methyl group is attached at fourth carbon atom with respect to hydroxy group; compound is named as, 4-Methyl phenol. [pic] • Depending on the position of substituted functional group with respect to the hydroxyl group, words like ortho (when the functional group is attached to the adjacent carbon atom), para (when the functional group is attached to the third carbon atom from the hydroxyl group), meta (when the functional group is attached to the second carbon atom from the hydroxyl group) are also used for the nomenclature of phenols. • Compounds with two or more –OH groups have special names: [pic] • Certain groups, e.g., -COOH, -CHO, -SO3H, if present in the ring, take priority; the –OH group is then used as a modifying prefix: STEP 5: Chemical Structure of Phenols (15 minutes). • The simplest way to draw the structure of phenol is [pic] • There is an interaction between the delocalized electrons in the benzene ring and one of the lone pairs on the oxygen atom. • This has an important effect on both the properties of the ring and of the -OH group. • One of the lone pairs on the oxygen overlaps with the delocalized ring electron system [pic] Giving a structure rather like this [pic] • The donation of the oxygen's lone pair into the ring system increases the electron density around the ring. That makes the ring much more reactive than it is in benzene itself. That is explored in another page in this phenol section. • It also helps to make the -OH group's hydrogen a lot more acidic than it is in alcohols. That will also be explored elsewhere in this section. STEP 6: Chemical Properties of Phenols (15 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | | | |What are the chemical properties of Phenols? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response

NTA Level 5 • Semester 1 • PST05106 Aromatic Organic Compounds of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 18 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 18: Aromatic Organic Compounds of Pharmaceutical Importance . Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define aromatic organic compounds • List aromatic compounds and their isomers • Explain nomenclature of aromatic organic compounds • Draw chemical structure of aromatic organic compounds • List chemical properties of aromatic organic compounds • Explain chemical reactions of aromatic organic compounds Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Aromatic Organic | | | |Presentation |Compounds | |3 |15 minutes | |Aromatic organic compounds and their| | | |Buzzing |Isomers | | | |Presentation | | |4 |15 minutes |Presentation |Nomenclature of Aromatic Organic | | | | |Compounds | |5 |15 minutes |Presentation |Chemical Structure of Aromatic | | | | |Organic Compounds | |6 |10 minutes |Presentation |Chemical Properties of Aromatic | | | |Brainstorming |Organic Compounds | |7 |40 minutes |Group |Chemical Reactions and Uses of | | | |discussion |Aromatic Organic Compounds | | | |Presentation | | |8 |05 minutes |Presentation |Key Points | |9 |05 minutes |Presentation |Evaluation | SESSION CONTENTS. STEP 1: Presentation of Session Title and Learning Tasks (5 minutes). READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Aromatic Organic Compounds (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Aromatic Organic Compounds? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | Aromatic hydrocarbons are those compounds that have molecular structures based on that of benzene C6H6 & resemble benzene in chemical behaviour. [pic] The Kekule Benzene structure • It suggests the presence of alternating single & double bonds. • Kekule suggested that 2 forms of benzene were in rapid equilibrium. [pic] STEP 3: Aromatic Organic Compounds and their Isomers (15 minutes). |Activity: Buzzing (10minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes | | | |What are the isomers of Aromatic organic compounds? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response on the flip chart/board. | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | • In a disubstituted benzene, three different position isomers are possible depending upon the position of one substituent with respect to the other. • Ortho (o−) is used to indicate that the relative position of the two substituents is 1,2−. Similarly, meta (m−) and para (p−) are used to indicate the relative positions 1,3− and 1,4− respectively. ortho, meta and para isomers of dimethylbenzene (xylene) [pic] STEP 4: Nomenclature of Aromatic Organic Compounds (15 minutes) • For many of the derivatives we simply prefix the name of the substituent group to the word benzene. • Other derivatives have special names, which show no resemblance to the name of the attached substituent group. [pic] [pic] [pic] STEP 5: Chemical Structure of Aromatic Organic Compounds (15 minutes) • Aromatic compounds are cyclic structures in which each ring atom is a participant in a bond, resulting in delocalized electron density on both sides of the ring. • Due to this connected network of bonds, the rings are planar, unlike the boat or table structures typical of cycloalkanes. Structure of benzene: resonance theory • “Whenever 2 or more structures can be written for a molecule and the only difference between the structures is in the position of electrons.” [pic] [pic] • If two groups are attached to the benzene ring their relative position must be indicated. The three possible isomers of di-substituted benzene are differentiated by use of the names; o ortho-(o) at carbon 1 & 2, o meta-(m) at carbon 1 & 3 o para-(p) at carbon 1 &4 [pic] [pic] [pic] • If the two groups are different, and neither gives a common name, the two groups are named successively, and the name is ended with –benzene: • When benzene ring is a substituent, it is named as the prefix “phenyl”. [pic] [pic] [pic] STEP 6: Chemical Properties of Aromatic Organic Compounds (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are chemical properties of Aromatic Organic Compounds? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | • Properties of Aromatic Hydrocarbons include that their major sources are Petroleum and coal. o Poly-aromatic hydrocarbons are defined as aromatic compounds with more than one benzene. o When they include in atmospheric pollution then it is known as carcinogenic in nature. • They go through electrophilic substitution reactions and nucleophile aromatic substitution. • Hydrocarbons which have multiple bonds are unsaturated in nature like alkenes and alkynes. o They tend to give addition reactions due to this unsaturation. • Due to resonance and give characteristic electrophilic substitution reactions aromatic hydrocarbons are stable. o The carbon ring acts as a nucleophile in these reactions and to form a substituted product an electrophile attack on benzene. • With the coming electrophile, one of the H-atom of a ring is substituted because of this the product also holds

NTA Level 5 • Semester 1 • PST05106 Ketones of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 17 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 17: Ketones of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define ketones • List ketones and their isomers • Explain nomenclature of ketones • Draw chemical structure of ketones • List chemical properties of ketones • Explain chemical reactions of ketones Resources Needed: • Flip charts, marker pens, and masking tape. • Black/white board and chalk/whiteboard markers. SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Ketones | | | |Presentation | | |3 |15 minutes |Presentation |Ketones and their Isomers | |4 |15 minutes |Presentation |Nomenclature of Ketones | |5 |15 minutes |Presentation |Chemical Structure of Ketones | |6 |15 minutes |Buzzing |Chemical Properties of Ketones | | | |Presentation | | |7 |35 minutes |Group |Chemical Reactions involving Ketones| | | |discussion | | | | |Presentation | | |8 |05 minutes |Presentation |Key Points | |9 |05 minutes |Presentation |Evaluation | SESSION CONTENTS. STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify. ASK students if they have any questions before continuing. STEP 2: Definition of Ketones (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What is Ketone? | | | |ALLOW few students to respond. | | | |WRITE their responses on the flip chart/ board. | | | |CLARIFY and SUMMARISE by using the content below | • A ketone is a carbonyl compound which has two alkyl (or aryl) groups bonded to the carbonyl carbon atom. [pic] • Aldehydes and Ketones are similar in structure, and they have similar properties • There are some differences, particularly in their reactions with oxidizing agents and with nucleophiles • In most cases Aldehydes are more reactive than Ketones STEP 3: Ketones and their Isomers (10 minutes). Ketones exhibit the following type of isomerism: • Chain (nuclear) Isomerism. o Aldehydes with 4 or more carbon atoms and ketones with five or more carbon atoms show chain isomerism. For example: [pic] • Position lsomerism. o Aromatic aldehydes and higher ketones give position isomers. For example: [pic] • Functional Isomerism. o The general formula of aldehydes, ketones, unsaturated alcohols oxiranes and oxolanes is CnH2nO o C3H6O has isomers as: [pic] STEP 4: Nomenclature of Ketones (15 minutes). • The longest chain carrying the –CHO group is considered as the parent structure. o Ketones are named by replacing the ‘-e’ of the corresponding alkane by the ending ‘-one’ o The alkane name becomes alkanone [pic] • The position of the attached group is indicated with number. The carbonyl carbon= 1 o When R is aromatic just the word ketone is added to the aromatic name • In open-chain ketones, we number the longest chain that includes the carbonyl carbon from the end closest to the carbonyl group, and we indicate the position of the carbonyl group by a number • In cyclic ketones, the carbonyl carbon atom is assigned the number 1 [pic] [pic] 4-hydroxy-4-methyl-2-pentanone 4-hydroxy-4-methylpentan-2-one • The common names of ketones are derived from the two alkyl groups that are attached to the carbonyl carbon & followed by the word ‘ketone’ [pic] • Some ketones have historical common names. o Dimethyl ketone is always called acetone, and alkyl phenyl ketones are usually named as the acyl group followed by the suffix -phenone. [pic] [pic] STEP 5: Chemical Structure of Ketones (15 minutes). • In a ketone, two carbon groups are attached to the carbonyl carbon atom. • The following general formulas, in which R represents an alkyl group and Ar stands for an aryl group, represent ketones. [pic] • In condensed formulas, we use CHO to identify an aldehyde rather than COH, which might be confused with an alcohol. • This follows the general rule that in condensed structural formulas H comes after the atom it is attached to (usually C, N, or O). [pic] Some simple structures of ketones [pic] STEP 6: Chemical Properties of Ketones (15 minutes). |Activity: Buzzing (5minutes). | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | | | |What are the chemical properties of Ketones? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response on the flip chart/board. | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | • Ketones undergoes addition reactions in presence of catalyst like finely divided platinum, palladium and nickel. • Ketones having at least one methyl group linked to the carbonyl carbon atom (i.e., methyl ketones) are oxidised by sodium hypohalite to sodium salts of carboxylic acids with one carbon atom less than that of the ketones. • Ketones can be reduced to a variety of compounds under different conditions with different reducing agents. • Ketones are oxidised only under vigorous conditions using powerful oxidising agents such as conc. HNO3, KMnO4/H2SO4, K2Cr2O7/H2SO4 etc. o Oxidation of ketones involves cleavage of bond between carbonyl carbon and a-carbon on either side of keto group giving a mixture of carboxylic acids. STEP 7: Chemical Reactions involving Ketones (35 Minutes) |Activity: Small Group Discussion (15 minutes) | | | |DIVIDE students into small groups | | | |ASK students to discuss in groups on the following questions. | |What are the chemical reactions involving Ketones? | | | |[pic]REFER Students to Book | | | |ALLOW students to discuss for 10 minutes. | | | |ALLOW each group to present for 5 minutes.

NTA Level 5 • Semester 1 • PST05106 Aldehydes of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 16 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 16: Aldehydes of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define aldehydes • List aldehydes and their isomers • Explain nomenclature of aldehydes • Draw chemical structure of aldehydes • List chemical properties of aldehydes • Explain chemical reactions of aldehydes Resources Needed: • Flip charts, marker pens, and masking tape. • Black/white board and chalk/whiteboard markers. SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Aldehydes | | | |Presentation | | |3 |10 minutes |Presentation |Aldehydes and their Isomers | |4 |15 minutes |Presentation |Nomenclature of Aldehydes | |5 |15 minutes |Presentation |Chemical Structure of Aldehydes | |6 |15 minutes |Buzzing |Chemical Properties of Aldehydes | | | |Presentation | | |7 |35 minutes |Group |Chemical Reactions involving | | | |discussion |Aldehydes | | | |Presentation | | |8 |05 minutes |Presentation |Key Points | |9 |05 minutes |Presentation |Evaluation | SESSION CONTENTS. STEP 1: Presentation of Session Title and Learning Tasks (5 minutes). READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Aldehydes (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Aldehydes? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | Aldehydes are compounds of the general formula RCHO (R may be aliphatic or aromatic group) Examples of aldehydes In aldehydes, the carbonyl group has a hydrogen atom attached to it together with either • a second hydrogen atom Or • More commonly, a hydrocarbon group which might be an alkyl group or one containing a benzene ring. [pic] ALDEHYDE STEP 3: Aldehydes and their Isomers (10 minutes). Aldehydes exhibit the following type of isomerism: • Chain (nuclear) Isomerism. o Aldehydes with 4 or more carbon atoms show chain isomerism. For example: [pic] • Position isomerism. o Aromatic aldehydes and higher ketones give position isomers. For example: [pic] • Functional Isomerism. o The general formula of aldehydes, ketones, unsaturated alcohols oxiranes and oxolanes is CnH2nO o C3H6O has isomers as: [pic] STEP 4: Nomenclature of Aldehydes (15 minutes). I. The longest chain carrying the –CHO group is considered as the parent structure. Aldehydes are named by replacing the ‘-e’ of the corresponding alkane by the ending ‘-al’ [pic] II. When R is aromatic just the word aldehyde is added to the aromatic name III.The common name of simple aldehydes end with ‘aldehyde’ Examples: Formaldehyde (=methanal) Acetaldehyde (=ethanal) Propionoaldehyde (=propanal) Butyraldehyde (=butanal) IV. If the aldehyde group is attached to a large unit (ring), the suffix carbaldehyde is used.[pic] [pic] STEP 5: Chemical Structure of Aldehydes (15 minutes). In an aldehyde, at least one of the attached groups must be a hydrogen atom. The following compounds are aldehydes: [pic] • In condensed formulas, we use CHO to identify an aldehyde rather than COH, which might be confused with an alcohol. • This follows the general rule that in condensed structural formulas H comes after the atom it is attached to (usually C, N, or O). [pic] Some structures of simple aldehydes [pic] STEP 6: Chemical Properties of Aldehydes (15 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | | | |What are the chemical properties of Aldehydes? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response on the flip chart/board. | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | • Aldehydes can be reduced to a variety of compounds under different conditions with different reducing agents. • Aldehydes are reduced to the corresponding alcohols by; o Addition of hydrogen in the presence of catalysts like finely divided platinum, palladium, nickel and ruthenium. o Treatment with chemical reagents such as sodium borohydride (NaBH4) or Lithium aluminium hydride (LiAlH4). • Aldehydes are easily oxdised to carboxylic acids on treatment with common oxidising agents like nitric acid, potassium permanganate, potassium dichromate etc. • Aldehydes respond to the Fehlings' test. o Fehlings' solution is an alkaline solution of copper sulphate containing sodium potassium tartrate (Rochelle Salt) as a complexing agent. o Aldehydes on warming with solution, give a red precipitate of cuprous oxide as a result of the redox reaction. o Aromatic aldehydes give very poor results in this test. STEP 7: Chemical Reactions involving Aldehydes (35 Minutes). |Activity: Small Group Discussion (15 minutes) | | | |DIVIDE students into small groups. | | | |ASK students to discuss in groups on the following questions | |What are the chemical reactions involving Aldehydes? | | | |[pic]REFER Students to Book | | | |ALLOW students to discuss for 10 minutes. | | | |ALLOW each group to present for 5 minutes. | | | |CLARIFY and SUMMARIZE by using the contents below | • Aldehydes undergo many reactions to give a wide variety of useful derivatives. • Their most common reaction is nucleophilic addition, addition of a nucleophile and a proton across the C = O double bond. • The reactivity of the carbonyl group arises from the electronegativity of the oxygen atom and the resulting polarization of the carbon-oxygen double bond. • The electrophilic carbonyl carbon atom is sp2 hybridized and flat, leaving it relatively unhindered and open to attack from either face of the double bond.

NTA Level 5 • Semester 1 • PST05106 Ethers of Pharmaceutical importance Pharmaceutical Organic Chemistry • Source Session/Topic 15 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 15: Ethers of Pharmaceutical importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define ethers • List ethers and their isomers • Explain nomenclature of ethers • Draw chemical structure of ethers • List chemical properties of ethers • Explain chemical reactions of ethers Resources Needed: • Flip charts, marker pens, and masking tape. • Black/white board and chalk/whiteboard markers. SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Ethers | | | |Presentation | | |3 |10 minutes |Presentation |Ethers and their Isomers | |4 |15 minutes |Presentation |Nomenclature of Ethers | |5 |15 minutes |Presentation |Chemical Structure of Ethers | |6 |15 minutes |Buzzing |Chemical Properties of Ethers | | | |Presentation | | |7 |35 minutes |Group |Chemical Reactions involving Ethers | | | |discussion | | | | |Presentation | | |8 |05 minutes |Presentation |Key Points | |9 |05 minutes |Presentation |Evaluation | SESSION CONTENTS. STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Ethers (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What are Ethers? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | • Ethers are compounds of formula R – 0 – R ', where R and R' may be alkyl groups or aryl (benzene ring) groups. • Ethers can be considered derivatives of water (HOH) or alcohols (ROH) by replacing an H with an R group. • In an alcohol, one hydrogen atom of water is replaced by an alkyl group. • In an ether, both hydrogens are replaced by alkyl groups. [pic] • The R groups in ethers can be alkyl, aryl, or alkenyl. • The R groups can be the same or different. • If the R groups are the same, the ethers are called symmetrical ethers. • If the R groups are different, the ethers are called unsymmetrical ethers. • Ethers can be cyclic or acyclic. • Rings that contain an atom other than carbon are called heterocyclic compounds. • Oxygen is the heteroatom in cyclic ethers. Examples of ethers [pic] • The most important commercial ether is diethyl ether, often called "ethyl ether’’, or simply "ether." STEP 3: Ethers and their Isomers (10 minutes). Aliphatic Ethers can give two different types of isomers. • Chain isomerism o Ethers with the same formula and having different carbon chain skeletons are called chain isomers. o Examples: [pic] • Functional isomers. o Ethers are isomeric with alcohols. o Example: [pic] is isomeric with ethyl alcohol C2H5OH • Metamerism o Isomers with the same molecular formula but different alkyl groups (around the functional group) are called metamers. An ether with formula C4H10O has 3 metamers. [pic] STEP 4: Nomenclature of Ethers (15 minutes). • The IUPAC system, generally used with more complicated ethers, is sometimes called the alkoxy alkane system. • The common nomenclature of ethers, which is sometimes called the alkyl alkyl ether system has also been widely used • IUPAC names use the more complex alkyl group as the root name, and the rest of the ether as an alkoxy group. • For example, cyclohexyl methyl ether is named methoxycyclohexane. • This systematic nomenclature is often the only clear way to name complex ethers. Example, [pic] [pic] |Table 1: Common Alkyl and Alkoxy Groups | |Alkyl Group |Name | |Alkoxy Group |Name | |CH3– |Methyl | |CH3O– |Methoxy | |CH3CH2– |Ethyl | |CH3CH2O– |Ethoxy | |(CH3)2CH– |Isopropyl | |(CH3)2CHO– |Isopropoxy | |(CH3)3C– |tert-Butyl | |(CH3)3CO– |tert-Butoxy | |C6H5– |Phenyl | |C6H5O– |Phenoxy | Common Names (Alkyl Alkyl Ether Names) • Common names of ethers are formed by naming the two alkyl groups on oxygen and adding the word ether. • Under the current system, the alkyl groups should be named in alphabetical order, but many people still use the old system, which named the groups in order of increasing complexity. • For example, if one of the alkyl groups is methyl and the other is t- butyl, the current common name should be "t-butyl methyl ether,’’ • But most chemists use the older common name, "methyl t-butyl ether" • If both groups are methyl, the name is "dimethyl ether.’’ • If just one alkyl group is described in the name, it implies the ether is symmetrical, as in "ethyl ether." STEP 5: Chemical Structure of Ethers (15 minutes). • Ethers are a class of organic compounds that contain an ether group. • An ether group is an oxygen atom connected to two alkyl or aryl groups. • They follow the general formula R-O-R’. The C-O-C linkage is characterized by bond angles of 104.5 degrees, with the C-O distances being about 140 pm. • The oxygen of the ether is more electronegative than the carbons. • Thus, the alpha hydrogens are more acidic than in regular hydrocarbon chains. [pic] STEP 6: Chemical Properties of Ethers (15 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes | | | |What are the chemical properties of Ethers? | | | |ALLOW pairs to respond on the question | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content in

NTA Level 5 • Semester 1 • PST05106 Acyl Chlorides of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 14 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 14: Acyl Chlorides of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define acyl chlorides • Explain nomenclature of acyl chlorides • Explain physical properties of acyl chlorides • Describe the preparation of acyl chlorides • Explain chemical reactions of acyl chlorides Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of acyl chlorides | | | |Presentation | | |3 |15 minutes |Presentation |Nomenclature of acyl chlorides | |4 |15 minutes |Presentation |Physical Properties of Acyl | | | | |Chlorides | |5 |20 minutes |Buzzing |Preparation of Acyl Chlorides | | | |Presentation | | |6 |40 minutes |Group |Chemical Reactions involving acyl | | | |discussion |chlorides | | | |Presentation | | |7 |05 minutes |Presentation |Key Points | |8 |10 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes). READ or ASK students to read the learning tasks and clarify. ASK students if they have any questions before continuing. STEP 2: Definition of Acyl Chlorides (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | |What are acyl chlorides? | | | |ALLOW few students to respond. | | | |WRITE their responses on the flip chart/ board. | | | |CLARIFY and SUMMARISE by using the content below | • Acyl chlorides as "acid derivatives". • A carboxylic acid such as ethanoic acid has the structure: [pic] • There are a number of related compounds in which the -OH group in the acid is replaced by something else. • Compounds like this are described as acid derivatives. • Acyl chlorides (also known as acid chlorides) are one example of an acid derivative. • In this case, the -OH group has been replaced by a chlorine atom. [pic] STEP 3: Nomenclature of Acyl Chlorides (15 minutes). • The easiest way of thinking about the names is to see the relationship with the corresponding. |carboxylic acid |acyl chloride |acyl chloride | |name |name |formula | |ethanoic acid |ethanoyl |CH3COCl | | |chloride | | |propanoic acid |propanoyl |CH3CH2COCl | | |chloride | | |butanoic acid |butanoyl |CH3CH2CH2COCl | | |chloride | | • The acyl group name is derived from the carboxylic acid name by replacing -oic acid by -ly. • If you have something substituted into the hydrocarbon chain, the carbon in the -COCl group counts as the number 1 carbon. • For example, 2-methylbutanoyl chloride is: [pic] • Note: Hardly anyone ever mentions methanoyl chloride, HCOCl – derived from methanoic acid. • That is because methanoyl chloride is very unstable, decomposing to give carbon monoxide and HCl. STEP 4: Physical properties of acyl chlorides (15 minutes). • Appearance o An acyl chloride like ethanoyl chloride is a colourless fuming liquid. o The strong smell of ethanoyl chloride is a mixture of the smell of vinegar (ethanoic acid) and the acrid smell of hydrogen chloride gas. o The smell and the fumes are because ethanoyl chloride reacts with water vapour in the air. • Solubility in water o Acyl chlorides can't be said to dissolve in water because they react (often violently) with it. o The strong reaction means that it is impossible to get a simple aqueous solution of an acyl chloride. • Boiling points o Taking ethanoyl chloride as typical: o Ethanoyl chloride boils at 51°C. o It is a polar molecule, and so has dipole-dipole attractions between its molecules as well as van der Waals dispersion forces. o However, it doesn't form hydrogen bonds. o Its boiling point is therefore higher than, say, an alkane of similar size (which has no permanent dipoles), but not as high as a similarly sized alcohol (which forms hydrogen bonds in addition to everything else.) STEP 5: Preparation of Acyl Chlorides (20 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes. | |How are acyl chlorides prepared? | | | |ALLOW pairs to respond on the question. | | | |WRITE their response on the flip chart/board. | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | • Acyl chlorides are prepared by treatment of carboxylic acids with thionyl (SOCl2). [pic] • Example, [pic] STEP 6: Chemical Reactions involving acyl chlorides (40 minutes). |Activity: Small Group Discussion (15 minutes) | | | |DIVIDE students into small groups | | | |ASK students to discuss in groups on the following questions | |What are the chemical reactions involving Esters? | |[pic]REFER Students to Book | |ALLOW students to discuss for 10 minutes | | | |ALLOW each group to present for 5 minutes | | | |CLARIFY and SUMMARIZE by using the contents below | • Substitution of the chlorine atom by other groups o Acyl chlorides are extremely reactive, and in their reactions the chlorine atom is replaced by other groups. o In each case, in the first instance, hydrogen chloride gas is produced as steamy acidic fumes. o However, in some cases the hydrogen chloride goes on to react with one of the substances in the reaction mixture. o Taking ethanoyl chloride as typical, the initial reaction is of this kind: [pic][pic] o The reactions involve compounds like water, alcohols and phenols, or ammonia and amines. o All of these particular cases contain a very electronegative element with an active lone

NTA Level 5 • Semester 1 • PST05106 Esters of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 13 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 13: Esters of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Define esters • Explain nomenclature of esters • Draw chemical structure of esters • List chemical properties of esters • Explain chemical reactions of esters Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board and chalk/whiteboard markers SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Esters | | | |Presentation | | |3 |15 minutes |Presentation |Nomenclature of Esters | |4 |15 minutes |Presentation |Chemical Structure of Esters | |5 |20 minutes |Buzzing |Chemical Properties of Esters | | | |Presentation | | |6 |40 minutes |Group |Chemical Reactions involving Esters | | | |discussion | | | | |Presentation | | |7 |05 minutes |Presentation |Key Points | |8 |10 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify. ASK students if they have any questions before continuing. STEP 2: Definition of Esters (10 minutes) |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What is Ester? | | | |ALLOW few students to respond. | | | |WRITE their responses on the flip chart/ board. | | | |CLARIFY and SUMMARISE by using the content below | • An ester (“carboxylic ester” in the textbook) is a derivative of a carboxylic acid in which there is a carbon group connected to the single- bonded oxygen: • In an ester, The H in the carboxyl group is replaced with an alkyl group. [pic] [pic] Some common esters are as follows; [pic] STEP 3: Nomenclature of Esters (15 minutes). • Name the alkyl or aromatic portion contributed by the “alcohol part” first. [pic] • The “acid part” is named as a carboxylic acid, with the -ic acid suffix changed to -ate [pic] [pic] STEP 4: Chemical Structure of Esters (15 minutes). • Esters contain a carbonyl center, which gives rise to 120-degree C-C-O and O-C-O bond angles due to sp2 hybridization. • Unlike amides, esters are structurally flexible functional groups because rotation about the C-O-C bonds has a lower energy barrier. • Their flexibility and low polarity affect their physical properties on a macroscopic scale. • They tend to be less rigid, leading to a lower melting point, and more volatile, leading to a lower boiling point, than the corresponding amides. • The pKa of the alpha-hydrogens, or the hydrogens attached to the carbon adjacent to the carbonyl, on esters is around 25, making them essentially non-acidic except in the presence of very strong bases. [pic] • An ester is characterized by the orientation and bonding of the atoms shown, where R and R’ are both carbon-initiated chains of varying length, also known as alkyl groups. • As usual, R and R’ are either alkyl groups or groups initiating with carbon. • Esters are derivative of carboxylic acids where the hydroxyl (OH) group has been replaced by an alkoxy (O-R) group. • They are commonly synthesized from the condensation of a carboxylic acid with an alcohol. STEP 5: Chemical Properties of Esters (20 minutes). |Activity: Buzzing (5minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes | | | |What are the chemical properties of Esters? | | | |ALLOW pairs to respond on the question | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | In acid hydrolysis • An ester reacts with water to produce a carboxylic acid and an alcohol. • An acid catalyst is required. [pic] Base hydrolysis Base hydrolysis is the reaction of an ester with a strong base. Produces the salt of the carboxylic acid and an alcohol. [pic] STEP 6: Chemical Reactions involving Esters (40 minutes). |Activity: Small Group Discussion (15 minutes) | | | |DIVIDE students into small groups | | | |ASK students to discuss in groups on the following questions | |What are the chemical reactions involving Esters? | | | |[pic]REFER Students to Book | | | |ALLOW students to discuss for 10 minutes | | | |ALLOW each group to present for 5 minutes | | | |CLARIFY and SUMMARIZE by using the contents below | Esterification Reaction • The simplest way to synthesize an ester is to heat a carboxylic acid with an alcohol or phenol (plus an acid catalyst). o The oxygen of the alcohol adds to the carboxyl group, splitting out a molecule of water in the process (an esterification reaction). [pic] • Since this reaction is a reversible reaction, it often reaches an equilibrium with a large amount of unreacted starting material still present. • Better yields are obtained using either acid chlorides or acid anhydrides as starting materials. o These reactions are nonreversible [pic] Examples [pic] Ester Hydrolysis • Esters may be broken apart under acidic conditions by water (a hydrolysis reaction) to form a carboxylic acid and an alcohol. [pic] • This is essentially the reverse reaction of the synthesis of esters from carboxylic acids and alcohols. Base hydrolysis (Saponification) Esters may be broken apart under basic conditions by sodium hydroxide (lye) or potassium hydroxide to form carboxylate salts and alcohols. [pic] This reaction is important in the production of soaps STEP 8: Key Points (05 minutes) • An ester is a chemical compound derived from carboxylic acid in which

NTA Level 5 • Semester 1 • PST05106 Carboxylic Acids of Pharmaceutical Importance Pharmaceutical Organic Chemistry • Source Session/Topic 12 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 12: Carboxylic Acids of Pharmaceutical Importance. Total Session Time: 120 minutes Prerequisites • None Learning Tasks. By the end of this session students are expected to be able to: • Define carboxylic acids • Explain nomenclature of carboxylic acids • Draw chemical structure of carboxylic acids • List chemical properties of carboxylic acids • Explain chemical reactions of carboxylic acids Resources Needed: • Flip charts, marker pens, and masking tape. • Black/white board and chalk/whiteboard markers. SESSION OVERVIEW |Step |Time |Activity/ |Content | | | |Method | | |1 |05 minutes |Presentation |Introduction, Learning Tasks | |2 |10 minutes |Brainstorming |Definition of Carboxylic Acids | | | |Presentation | | |3 |15 minutes |Presentation |Nomenclature of Carboxylic Acids | |4 |15 minutes |Presentation |Chemical Structure of Carboxylic | | | | |Acids | |5 |15 minutes |Buzzing |Chemical Properties of Carboxylic | | | |Presentation |Acids | |6 |40 minutes |Group |Chemical Reactions involving | | | |discussion |Carboxylic Acids | | | |Presentation | | |7 |10 minutes |Presentation |Key Points | |8 |10 minutes |Presentation |Evaluation | SESSION CONTENTS STEP 1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing. STEP 2: Definition of Carboxylic Acids (10 minutes). |Activity: Brainstorming (5 minutes) | | | |Ask students to brainstorm on the following question: | | | |What is carboxylic acid? | | | |ALLOW few students to respond | | | |WRITE their responses on the flip chart/ board | | | |CLARIFY and SUMMARISE by using the content below | • The combination of a carbonyl group and a hydroxyl on the same carbon atom is called a carboxyl group. • Compounds containing the carboxyl group are distinctly acidic and are called carboxylic acids. [pic] Condensed structures [pic] • Therefore, carboxylic acids are acidic organic compounds containing the carboxyl group as a functional group, attached to hydrogen HCOOH or an alkyl group as RCOOH or an aryl group as ArCOOH • The general formula would be CnH(2n+1)COOH or R-CO2H. STEP 3: Nomenclature of Carboxylic Acids (15 minutes). IUPAC Names • The IUPAC nomenclature for carboxylic acids uses the name of the alkane that corresponds to the longest continuous chain of carbon atoms. • The final -e in the alkane name is replaced by the suffix -oic acid. • The chain is numbered, starting with the carboxyl carbon atom, to give positions of substituents along the chain. In naming, the carboxyl group takes priority over any of the functional groups discussed previously =Examples [pic] [pic] [pic] [pic] [pic] [pic] [pic] [pic] Some more examples of traditional names most widely used are: • Formic acid- HCOOH • Acetic acid – CH3COOH • Propionic acid – CH3CH2COOH • Butyric acid – CH3(CH2)2COOH • Valeric acid – CH3(CH2)3COOH • Caproic acid – CH3(CH2)4COOH • Capyrylic acid – CH3(CH2)6COOH • Capric acid – CH3(CH2)8COOH STEP 4: Chemical Structure of Carboxylic Acids (15 minutes) • The CO2H unit is planar and consistent with sp2 hybridization and a resonance interaction of the lone pairs of the hydroxyl oxygen with the π system of the carbonyl. | Carboxylic Acid | | | | |Structure | | |Ethanoic acid |CH3CO2H | | |Propanoic acid |CH3CH2CO2H | | |Fluoroethanoic acid |CH2FCO2H | | |Chloroethanoic acid |CH2ClCO2H | | |Dichloroethanoic acid |CHCl2CO2H | | |Trichloroethanoic acid |CCl3CO2H | | |Nitroethanoic acid |O2NCH2CO2H | | STEP 5: Chemical Properties of Carboxylic Acids (15 minutes). |Activity: Buzzing (10minutes) | | | |ASK students to pair up and buzz on the following question for 5 | |minutes | | | |What are the chemical properties of carboxylic acid? | | | |ALLOW pairs to respond on the question | | | |WRITE their response on the flip chart/board | | | |CLARIFY and SUMMARIZE by using the content in the table 1 below | The following are chemical properties of carboxylic acids; Acidity of Carboxylic Acids Carboxylic acids are weak acids and their carboxylic anions are strong conjugate bases are slightly alkaline due to the hydrolysis of carboxylate anion compared to other species, the order of acidity and basicity or corresponding conjugate bases are as follows: Acidity RCOOH > HOH > ROH > HC[pic] CH > NH3 > RH Basicity RCOO– < HO– < RO– < HCC– < NH2-< R– Reaction of Carboxylic Acids with Metals • The carboxylic acids react with metals to liberate hydrogen and are soluble in both NaOH and NaHCO3 solutions. For example; ▪ 2CH3COOH + 2Na → 2CH3COO–Na+ + H2 ▪ CH3COOH + NaOH → CH3COO–Na+ + H2O ▪ CH3COOH + NaHCO3 → CH3COO–Na+ + H2O + CO2 • Carboxylic acids dissociate in water to give resonance stabilised carboxylate anions and hydronium ion. [pic] Effect of substituents on the acidity of Carboxylic Acids • Any factor that stabilizes the anion more than it stabilizes the acid would increase the acidity of carboxylic acids. • While any factor that decreases the stability of anion would decrease the acidity of carboxylic acids. • Electron withdrawing groups disperse the negative charge and thus stabilize the anion which results in increase in acidity of the carboxylic acids. • Electron donating groups intensify the negative charge and destabilize the anion which results in decrease in acidity of carboxylic acid. [pic] Conversion of Carboxylic Acids into functional derivatives • Carboxylic acids can be converted into number of other compounds (known as derivatives of carboxylic acids or simply acid derivatives) by replacement of its –OH group by a Cl, OR or NH2 . o Replacement of -OH by -Cl forms acid chlorides. o Replacement of -OH by -OR forms ester. o Replacement of -OH