Hydrochloric Acid → 4-amino-6-(4-pyridinyl)-3(2H)-pyridazinone

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Reaction Steps

The above procedure of Example G-1 first procedes through the acid azide as seen by the following isolation of the acid azide as its monohydrochloride: To a solution chilled in an ice bath and containing 3.0 g. of 2,3-dihydro-3-oxo-6-(4-pyridinyl)-4-pyridazinecarboxylic acid hydrazide and 60 ml. of 6 N hydrochloric acid was added dropwise with stirring a solution containing 3.0 g. of sodium nitrite in 10 ml. of water over a 30 minute period. The reaction mixture was then stirred for an additional 1 hour, allowing the reaction mixture to warm up to room temperature. The separated solid was collected, washed with water and dried in a vacuum oven over P2O5 at 25° C. for 48 hours to yield 3.0 g. of 2,3-dihydro-3-oxo-6-(4-pyridinyl)-4-pyridazinecarboxylic acid azide monohydrochloride, m.p. >300° C.

Provenance & Evidence