Reactions of π-electron rich 1,2,4-triazines with organolithium nucleophiles

Abstract

3,5-Bis(trimethylsilyloxy)-1,2,4-triazine 1 and 3-methylthio-5-methoxy-1,2,4-triazine 6 were subjected to reactions with organolithium reagents at low temperatures. An unexpected regioselectivity in the addition of butyllithiums to 1, which was strongly dependent on the temperature and substituents, was observed. For phenyllithium there was competition between N(1)–C(6) addition and C(5) substitution. No addition of butyllithiums to 6 was detected, only isolated reaction products showing zwitterionic structures.