Abstract
Cyanomethylation of 4, 5, 6, 7-tetrahydro-6, 6-dimethyl-7-oxobenzothiazole (VII), which was prepared from 4, 4-dimethyl-1, 3-cyclohexanedione (I) in several steps, afforded the cyano alcohol (VIII). Compound VIII was treated with lithium aluminum hydride and the resulting amino alcohol (IX) was converted into 7-(2-aminoethyl)-4, 7-dihydro-6, 7-dimethylbenzothiazole (XI) by Wagner-Meerwein rearrangement. Reaction of XI with bromine gave the salt (XII). Treatment of XII with potassium carbonate produced the bridged aziridine (XIII), which was cleaved to the thiazolo [5, 4-f] morphan (4, 5, 6, 7, 8, 9-hexahydro-5, 9-methanothiazolo [4, 5-d] azocine) derivative (XVI) by the action of benzoyl bromide. Dehydrobromination followed by hydrolysis of the benzoyl group led XVI to 5-methyl-9-methylenethiazolo [5, 4-f] morphan (XVIII). Stereospecific hydrogenation of XVIII yielded the 9α-methyl isomer (XIX), whose N-methylation by the Eschweiler-Clarke method completed the synthesis of the desired thiazolo [5, 4-f] morphan (XX). The molecular structure of the oxalate of XIX was established by X-ray analysis.
