Hydrochloric Acid → Hydralazine Hydrochloride

Participants

Reaction Steps

Again according to the disclosure in the '397 application, hydralazine free base 25 g (1 part by weight) was heated in 165 mL (6 to 7 parts by volume) of 15% hydrochloric acid to a temperature of 70-80° C. The solution was filtered hot to remove traces of insoluble materials that were undesired by-products of the preceding step. One hundred sixty five milliliters of ethanol (6 to 7 parts by volume) was added to the filtrate. As the resulting solution cooled to 25° (ambient temperature) and then further cooled to 3-8° C., a pale yellow precipitate of the desired product, hydralazine hydrochloride, solidified. The obtained yield is 65% (the reported yields in the '397 application were 80-90%).

Provenance & Evidence