Amines(organic ammonia)NH3-NH2R or RNH21o amine(R .ppt

1、Amines(organic ammonia) :NH3:NH2R or RNH2 1o amine (R may be Ar):NHR2 or R2NH 2o amine:NR3 or R3N 3o amineNR4+ 4o ammonium salt,NB amines are classified by the class of the nitrogen, primary amines have one carbon bonded to N, secondary amines have two carbons attached directly to the N, etc. Nomenc

2、lature. Common aliphatic amines are named as “alkylamines”,Salts of amines: change amine ammonium + anionchange aniline anilinium + anionCH3CH2CH2NH3+Cl-n-propylammonium chloride(C6H5NH3)2SO4anilinium sulfate,Amines, physical properties:Nitrogen is sp3 hybridized, amines are polarand can hydrogen bo

3、nd.mp/bp are relatively high for covalent substancesamines are basic and will turn litmus blue insoluble in water (except for four-carbons or less)soluble in 5% HCl“fishy” smell ,RNH2 + HCl RNH3+ + Cl-water waterinsoluble solubleRNH3+ + OH- RNH2 + H2Owater watersoluble insoluble1. test for amines2.

4、can be used to separate amines from neutralor acidic organic compounds,Amines, syntheses: Reduction of nitro compoundsAr-NO2 + H2,Ni Ar-NH2 Ammonolysis of 1o or methyl halides R-X + NH3 R-NH2 Reductive aminationR2C=O + NH3, H2, Ni R2CHNH2 Reduction of nitrilesR-CN + 2 H2, Ni RCH2NH2 Hofmann degradat

5、ion of amidesRCONH2 + KOBr RNH2,1. Reduction of nitro compounds:,Ammonolysis of 1o or methyl halides.,3. Reductive amination:,Avoids E2,Reductive amination via the imine.,Reduction of nitrilesR-CN + 2 H2, catalyst R-CH2NH21o amineR-X + NaCN R-CN RCH2NH2primary amine with one additional carbon(R must

6、 be 1o or methyl),5. Hofmann degradation of amides,Amines, syntheses: Reduction of nitro compounds 1o Ar Ar-NO2 + H2,Ni Ar-NH2 Ammonolysis of 1o or methyl halides R-X = 1o,CH3 R-X + NH3 R-NH2 Reductive amination avoids E2R2C=O + NH3, H2, Ni R2CHNH2 Reduction of nitriles + 1 carbonR-CN + 2 H2, Ni RCH

7、2NH2 Hofmann degradation of amides - 1 carbonRCONH2 + KOBr RNH2,Outline possible laboratory syntheses for each of the following amines, starting with toluene. Use a different method for each compound.,First decide which method you are going to use for which compound,1. nitration,2. ammonolysis,3. Reductive amination,4. Reduction of nitrile,5. Hofmann degradation,