GB967177A — A method for preparing pyrrolidinones and piperidinones

USPTO Abstract

Pyrrolidinones and piperidinones with, in the 5 and 6 positions respectively, a hydrogen atom and optionally a hydrocarbon group which may be joined to another carbon atom in the ring to form a cyclic group are prepared by reacting corresponding pyrrolidinones or piperidinones substituted in the 5 and 6 position respectively by a hydroxyl, alkoxyl, or an alkylamino group in which the alkyl group may be substituted by hydroxyl, aryl, or alkylamino groups and the optional second hydrocarbon substituent, with hydrogen in the presence of a hydrogenolysis catalyst. Lists of starting compounds are given, among them compounds of formula <FORM:0967177/C1/1> in which R represents hydrogen, an alkyl group (1-18C), an aryl group (up to 10C) an aralkyl group (up to 18C), an alkaryl group (up to 24C), an alkarylalkyl group (up to 30C), an alkoxyalkyl group (3 to 24C), hydroxyalkyl (2-12C), an alkylamino alkyl (3-18C), or a dialkylamino alkyl group (3-18C) in which the dialkyl substituents may be joined to form a cyclic group, R1 represents hydrocarbon groups (1-10C), R2 represents a hydroxyl, alkoxyl (1-4C) alkylamino (1-12C) which may be substituted by a hydroxyl, alkoxyl, aryl or alkylamino group, and D is a divalent chain containing 2 to 3C atoms which yield compounds of formula <FORM:0967177/C1/2> Catalysts for the hydrogenation are Raney nickel or cobalt, cobalt or nickel with ammonia, cobalt-copper, nickel-cobalt, palladium, platinum, rubidium and ruthenium with or without a carrier such as activated alumina or clays, silica gel, charcoal, asbestos and pumice. A solvent, such as hydrocarbons, alcohols and ethers may be present and the product is separated by filtration and stripping of the solvent. The starting materials may be obtained by the cyclisation of g - and d - oxonitriles followed by hydration with aqueous alkali. Examples describe the preparation of 3,3,5-trimethyl -2- pyrolidinone, 3,5-dimethyl -3- neopentyl -2- pyrrolidinone, 5,5-dimethyl -2- piperidinone, 4,5-dimethyl -2- pyrrolidinone, 1-benzyl-3, 3, 5-trimethyl -2- pyrrolidinone, 1-(2-phenylethyl)-3,3,6-trimethyl-2- piperidinone, 1-(2-hydroxy propyl)-5, 5-dimethyl -2- piperidinone, 1-(2-methyl aminoethyl)-3, 5-dimethyl -3- hexyl -2- pyrrolidinone spiro {3,3-dimethylbicyclo (2,2,1) heptane-2, 31-[51-methyl -21- pyrrloidinone]}, 1 -ptolyl-3, 3, 5-trimethyl -2- pyrrolidinone, 1-(2-hydroxy ethyl)-3, 5-bis-(2-methylpropyl)-3-methyl -2- pyrrolidinone, 1-(3-dimethyl-aminopropyl)-4, 6-dimethyl -4- neopentyl -2- piperidinone, 3, 3-pentamethylene-2, 3, 3a, 4, 5, 6, 7, 7a-octahydroindol -2- one, 3-methyl-1, 3, 3a, 4, 5, 6, 7, 7a-octahydroisoindol -1- one, 5, 6-dimethyl -2- piperidinone, 5-methyl -2- pyrrolidinone, 3, 3, 6-trimethyl-2, 3, 3a, 4, 5, 6, 7, 7a-octahydroindol-2-one, 6-oza -7- oxo 1, 3, 3-trimethylbicyclo (3, 2, 1) octane, 5-ethyl -5- butyl -2- piperidinone, 3, 5-dihexyl -3- methyl -2- pyrolidinone, 1, 3, 3, 5-tetramethyl -2- pyrrolidinone, 1, 3-dimethyl-3, 5-dihexyl -2- pyrrolidinone, 1-ethyl-3, 3, 6-tri, methyl -2- piperidinone and 1-dodecyl-3, 5, 5-trimethyl -2- piperidinone.