Synthesis and some reactions of 3,4,5,6-tetrahydro-3,6-dimethyl-2,6-.methano-3-benzazocin-1(2H)-one (2,5-dimethyl-8-oxo-6,7-benzomorphan)

Abstract

In a Beckmann rearrangement the oxime of the title compound (1) gave 1,3,4,5,6,7-hexahydro-4,7-dimethyl-3,7-methano-1,4-benzodiazonin-2-one (3). Hydrolysis of this product (3) with hydrochloric acid gave 4-(2-aminophenyl)-1,4-dimethylpiperidine-2-carboxylic acid (5)(see Scheme), which was converted into its ethyl ester (7) and cyclised in polyphosphoric acid to give back starting material (3). With tetraphosphorus decasulphide the lactam (3) gave the thiolactam (10). Whereas lactam (3) was alkylated on nitrogen with methyl iodide, to give (8), the thiolactam (10) was alkylated on sulphur, to give (11). Lactams (3) and (8) were reduced with lithium aluminium hydride. Reduction of the title compound (1) with sodium cyanohydridoborate in the presence of ammonium acetate gave a mixture containing 1-α-amino-(14) and 1-α-hydroxy-1,2,3,4,5,6-hexahydro-3,6-dimethyl-2,6-methano-3-benzazocine (15).