SYNTHESIS OF 1-METHYL-6-PHENYLIMIDAZO(4,5-B)PYRIDINE

摘要

PROBLEM TO BE SOLVED: To safely obtain the subject compound used as a precursor for a carcinogenic substance useful for the explication of carcinogenic mechanisms and the like in a high yield in a large amount and at a low cost by a new method comprising reacting 2-amino-3-methylamino-5-phenylpyridine with formic acid. SOLUTION: 2-Amino-3-methylamino-5-phenylpyridine of formula I is reacted with formic acid or an orthoformic acid ester (e.g. orthoformic acid ethyl ester) and acetic anhydride to produce the objective compound of formula II. The compound of formula I is preferably obtained by reacting 2-amino-3-bromo-5- phenylpyridine of formula III with liquid methylamine in the presence of a catalyst such as a copper salt. The compound of formula III may be obtained by a known method comprising reacting 3-phenylpyridine as a starting raw material with sodium amide and subsequently reacting the obtained 2-amino-5- phenylpyridine with bromine.