Metallation reactions XXVII. Metallation of (methylthio)anilines

The metallation reactions of (methylthio)anilines with organolithium reagen ts and with the butyllithium-potassium tert-butoxide superbasic mixture are here described. The results show that the para isomer when treated with bu tyllithium gave a mixture of products with no selectivity. Using tert-butyl lithium or superbases we obtained the substitution of the thiomethyl hydrog en. Moreover, superbase allowed to prepare the disubstituted product with t he new groups in the thiomethyl and in ortho to this group. On the other si de, both or tho and meta isomers were lithiated at the thiomethyl carbon by butyllithium and the other reagents. Starting from the unalkylated amine w e prepared through three successive one-pot monometallations N, N -disubsti tuted amines with equal or different groups and bearing an alkylthio chain as long as wanted. (C) 2001 Elsevier Science B.V. All rights reserved.