Hydrazine hydrate (1:1) → 4,4a,5,6-tetrahydrothieno[2',3':2,3]thiepino[4,5-c]pyridazin-3(2H)-one

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Reaction Steps

A suspension of 2.0 g of 4-oxo-4,5,6,7-tetrahydrothieno[2,3-b]thiepin-5-acetic acid and 0.6 g of hydrazine hydrate in 20 ml of ethanol is refluxed under heating for 5 hours. After cooling, the precipitated crystals are collected by filtration and recrystallized from a mixed solvent of chloroform and ethanol to give 1.4 g of 4,4a,5,6-tetrahydrothieno[2',3':2,3]thiepino[4,5-c]pyridazin-3(2H)-one as white crystals, melting at 215°-217° C.

Provenance & Evidence