Hydrazine hydrate (1:1) → Hydralazine

Participants

Reaction Steps

To a 2-L, 3-necked, round-bottom flask fitted with a temperature probe and condenser were charged 700 mL of ethanol and 7.6 mole equivalents (630 mL) of hydrazine hydrate, and the solution was cooled to <10° C. One (1) mole equivalent (280 g) of 1chlorophthalazine (solid) was added in portions at a rate to maintain the solution temperature at <20° C. The solution was stirred and heated to 60–70° C. After 1 hour at temperature, the hot solution was filtered to remove any insoluble by-products, and the filtrate was cooled to 0–5° C. A light yellow solid formed in the cold solution, and was isolated by filtration and washed with cold ethanol. The resulting product, hydralazine free base, was dried to constant mass and characterized. Typical yields were in the range 77–80%. The hydralazine thus obtained could be used in the next step without purification.

Provenance & Evidence