Formation and reaction of N-acyl- and N-methanesulfonyl-1-(3,4-dimethoxy)benzyl-7-acetoxy-1,2,3,4,6,7-hexahydro-7-methoxy-6-oxoisoquinolines (o-quinol acetates)

Oxidation of N-acyl- and N-methanesulfonyl-1,2,3,4-tetrahydro-7-methoxyisoq uinolin-6-ols (7) with lead tetraacetate in dichloromethane produced quanti tatively title compounds (o-QAs) (8). Treatment of N-trifluoroacetyl and N- formyl o-QAs (8a,b) with acetic acid at 30-40 degreesC afforded N-trifluoro acetyl and N-formyl p-QAs (9a,b), while that of N-acetyl, N-ethoxycarbonyl and N-methanesulfonyl congeners (8c-e) gave N,N-dialkylacetamide (10c), eth yl N,N-dialkylcarbamate (10d), and N,N-dialkylmethanesulfonamide (10e), whi ch are formed by elimination of a benzylic proton and subsequent cleavage o f a C1-C8a bond in 9c-e. (C) 2000 Elsevier Science Ltd. All rights reserved .