Naphthalene-catalysed lithiation of chlorinated nitrogenated aromatic heterocycles and reaction with electrophiles

摘要

Naphthalene catalysed reductive lithiation of various cholorazines (1, 7, 10, 13) in the presence of different electrophiles yields, after hydrolysis, the expected functionalised heterocycles with one (2, 8), two (11, 14a-d) and three nitrogen atoms in the ring (14e,f). This methodology allowed us to trap in situ the lithium imine derived from the reaction of 2-pyridyllithium with benzonitrile, by reaction with a Grignard reagent in the presence of titanium alkoxides. 2,4-Dimethoxypyrimidines (14a,c,d) are demethylated under acidic conditions to give the corresponding uracil derivatives 16. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 65]