Metallation reactions XXVII.: Metallation of (methylthio)anilines

The metallation reactions of (methylthio)anilines with organolithium reagents and with the butyllithium–potassium tert-butoxide superbasic mixture are here described. The results show that the para isomer when treated with butyllithium gave a mixture of products with no selectivity. Using tert-butyllithium or superbases we obtained the substitution of the thiomethyl hydrogen. Moreover, superbase allowed to prepare the disubstituted product with the new groups in the thiomethyl and in ortho to this group. On the other side, both ortho and meta isomers were lithiated at the thiomethyl carbon by butyllithium and the other reagents. Starting from the unalkylated amine we prepared through three successive one-pot monometallations N,N-disubstituted amines with equal or different groups and bearing an alkylthio chain as long as wanted.