The synthesis of tetrahydroquinolines related to virantmycin

Abstract

4-Substituted anilines react with 1-methoxymethyl-1-butyl-3- trimethysilylpropargyl chloride but not with 1,1-dibutyl-3- trimethylsilylpropargyl chloride, to form the corresponding substituted N-propargylanilines. These anilines cyclise, using cuprous chloride, in the presence of trifluoroacetic anhydride, and, when the aniline substituent is electron donating, to give 6-substituted 2-butyl-2-methoxymethyl-1- trifluoroacetyl-1,2-dihydroquinolines. Chlorination, followed by selective dechlorination using sodium cyanoborohydride, of the 6-methyl product yields 2-butyl-2-methoxymethyl-3-chloro-6-methyl-1-trifluoroacetyl-1,2,3, 4-tetrahydroquinoline which has the same relative stereochemistry as that in the antiviral compound, Virantmycin.