Reaction of N-methylsulfonyl- and N-(p-tolylsulfonyl)-2-(cyclopent-1-en-1-yl)anilines with bromine in the presence of potassium thiocyanate and in methanol

The reactions of N-methylsulfonyl- and N-(p-tolylsulfonyl)-2-(cyclopent-1-en-1-yl)-6-methylaniline with molecular bromine in the presence of potassium thiocyanate gave N-methylsulfonyl- and N-(p-tolylsulfonyl)-2-(5-isothiocyanatocyclopent-1-en-1-yl)-6-methylanilines. N-Methylsulfonyl-2-(cyclopent-1-en-1-yl)-6-methylanihne reacted with bromine in methanol in the presence of NaHCO3 or with CuBr2 in MeOH to afford N-methylsulfonyl-2-(5-methoxycyclopent-1-en-1-yl)-6-methylanihne. The reaction of N-methylsulfonyl-2-(5-isothiocyanatocyclopent-1-en-1-yl)-6-methylaniline with diethylamine led to the formation of N-methylsulfonyl-2-{5-[diethylamino(thioxo)methyl]aminocyclopent-1-en-1-yl}-6-methylanihne which was converted into 5-methyl-4-methylsulfonyl-2,3,3a,4-tetrahydrocyclopenta[b]indole by heating with potassium hydroxide.