Verbesserungen in der Herstellung von 4-Oxopiperidinverbindungen und gewisser neuer 4-Oxopiperidinverbindungen

摘要

1,195,907. 2,2 - Dimethyl - 4 - oxo - piperidines. SANKYO CO. Ltd. 24 July, 1967 [23 July, 1966 (2)], No. 33939/67. Heading C2C. Novel compounds of the general formula where R 1 and R 2 are alkyl groups or, together with the C atom to which they are attached, form a saturated 5- or 6-membered homocyclic ring or a group of the formulµ where R 3 and R 4 are alkyl groups or, together with the C atom to which they are attached, form a saturated 5- or 6-membered homocyclic ring, are prepared by (A) reacting diacetone alcohol, NH 3 and a compound of the general formula R 1 (R 2 )C=O in the presence of a Lewis acid or (B) reacting 2,2,4,4,6-pentamethyl-2,3,4,- 5-tetrahydropyrimidine with water and a Lewis acid. 2,2,6,6 - Tetramethyl - 4 - oxo - piperidine is prepared from diacetone alcohol, NH 3 and acetone in the presence of CaCl 2 or from 2,2,4,4,- 6 - pentamethyl - 2,4,5,6 - tetrahydropyrimidine and water in the presence of ZnCl 2 , CaCl 2 .2H 2 O or picric acid. Use of cyclohexanone in reaction scheme (A) yields a spiro compound-l-aza-2,2- dimethyl-4-oxo-spiro-(5,5)-undecane.