Pharmaceutical Organic Chemistry 1 Lecture 6: Alcohols and Amines PDF

Nile Valley University Faculty of Pharmacy Pharmaceutical Chemistry Department Pharmaceutical Organic Chemistry 1 (PC 102) Lecture 6 Alcohols and amines Alcohols (ROH) Classification of alcohols 1. Alcohol family is classif...

Nile Valley University Faculty of Pharmacy Pharmaceutical Chemistry Department Pharmaceutical Organic Chemistry 1 (PC 102) Lecture 6 Alcohols and amines Alcohols (ROH) Classification of alcohols 1. Alcohol family is classified according to the type of carbinol carbon atom (the one bonded to the-OH group) into;10,20,30. Classification of alcohols 2. Alcohols can also be classified according to Number of hydroxyl groups into; -Monohydric alcohol (one OH), ethanol. -Dihydric alcohol (two OH), ethylene glycol -Trihydric alcohol (three OH), glycerol -Polyhydric alcohol (more than 3 OH), sorbitol. I-Nomenclature of alcohols A) Common name: the name of the alkyl group followed by the word’’alcohol’’ CH3CH2OH ethyl alcohol CH3OH methyl alcohol. B) IUPAC name: 1- Name the longest carbon chain that contains the carbon atom bearing the - OH group. Drop the final -e from the alkane name and add the suffix -ol to give the root name → alkanol. 2- Number the longest carbon chain starting at the end nearest the hydroxyl group, and use the appropriate number to indicate the position of the - OH group (The hydroxyl group takes precedence over double and triple bonds). 3- Name all the substituents and give their numbers. B) IUPAC name: II- Preparation of Alcohols 1- From alkene: ) See lecture 3) 2- From alkyl halide: Nucleophilic Substitution on an alkyl halide II- Preparation of Alcohols 3- From aldehydes and ketones: (See lecture 5) a. By reduction b. Using Grignard reagent 4- From carboxylic acids: (See lecture 5) 5- From of epoxides III. Physical Properties Lower alcohols are water miscible due to H-bonding with water. ↑ length of hydrocarbon portion ↑ hydrophobicity ↓ water solubility. Alcohols have ↑ B.P. due intermolecular H-bonding Branching increases distance between molecules and hence decrease B.P.  IV Reactions of alcohols 1) Reaction with active metals (Na, Li): Relative reactivity of alcohols towards metals: CH3OH > 1o alcohol > 2o > 3o alcohol 2) Ester formation Order of reactivity of alcohols: 1o˃ 2o˃ 3o  3) Oxidation of alcohols: 1o alcohols 2o alcohols 3o alcohols resist the oxidation under the previous conditions 4) Reaction with hydrogen halides: 5) Reactions with Grignard reagent Alcohol Alkane  Amines RNH2 Classification Nomenclature Derived from the alkane name by replacing suffix –e with suffix –amine.  Note: The –COOH group and –OH take priority over NH2 group II-Preparation of amines: 1) Partial reduction of nitrogenous compounds : ( for aliphatic amines) 2. Hofmann Degradation (prepare only 1 amines):  Basicity Of Amines Base strength : *Alkyl groups are electron releasing, they increases the basicity of amines. Electron-donating (releasing) groups on N atom increase the basic activity Electron withdrawing groups decrease the basic property Physical properties Boiling points of amines is increase with increasing relative molecular mass. Amines are polar compounds and both primary and secondary amines associate by intermolecular hydrogen bonding.  Reactions of amines: 1-Salt formation (alkyl ammonium salts): 2-Acylation of Amines: 3-Reaction of amines with nitrous acid Primary aliphatic amines: react with nitrous acid give alkyl diazonium ions