The synthesis of 7-substituted-2, 3-dihydropyrido [4, 3-d]pyridazine-1, 4-diones and 1, 4-Dioxo-7-substituted-1, 2, 3, 4-tetrahydropyrido[4, 3-d]pyridazine 6-oxides from methyl ketones

Abstract

A general four-step transformation of alkyl, cycloalkyl, aryl, and heteroaryl methyl ketones via 3-(dimethylamino)-1-substituted-prop-2-en-1-ones, followed by microwave [2+2] cycloaddition of dimethyl acetylenedicarboxylate, cyclization of (2E, 3E)-2-[(dimethylamino)methylene]-3-(2-substituted)succinates with ammonia or hydroxylamine hydrochloride into 2-substituted-pyridine-4, 5-dicarboxylates and their N-oxides and final cyclization with hydrazine hydrate into of 7-substituted-2, 3-dihydropyrido[3, 4-d]pyridazine-1, 4-diones and 1, 4-dioxo-7-substituted-1, 2, 3, 4-tetrahydropyrido[ 4, 3-d]pyridazine 6-oxides is shown.