Syntheses of nitrogen-containing heterocyclic compounds. XLIV. Syntheses of 5-substituted 1,6-naphthyridine derivatives using the Reissert compound of 1,6-naphthyridine (author's transl)

Abstract

1, 6-Naphthyridine-5-carboxamide (VI), 1, 6-naphthyridine-5-carboxylic acid (VII), and benzaldehyde were obtained by acid hydrolysis of 5-benzoyl-5, 6-dihydro-1, 6-naphthyridine-5-carbonitrile (III). Reaction of III with a Grignard reagent (CH3MgBr, PhMgBr) gave 1, 6-naphthyridine-5-carbonitrile (IX) by reaction with methylmagnesium bromide, and IX, VI, and α, α-diphenyl-5-(1, 6-naphthyridine) methanol (X) by reaction with phenylmagnesium bromide. Alkylation of III with methyl iodide, using a phasetransfer catalyst, gave 6-benzoyl-5, 6-dihydro-1, 6-naphthyridine-5-carbonitrile (XIII), and alkaline hydrolysis of XIII afforded 5-methyl-1, 6-naphthyridine (II). Reaction of III with 3, 4-dimethyoxbenzyl chloride gave 5-(3, 4-dimethoxybenzyl)-1, 6-naphthyridine (XV).