Phosphorus oxychloride → 1-Chlorophthalazine

Participants

Reaction Steps

The process according to one embodiment of this invention comprises the steps of: a) reacting phthalazinone with an approximately equimolar equivalent of phosphorous oxychloride at a specific temperature to produce a 1-chlorophthalazine salt; b) isolating the 1-chlorophthalazine salt formed in step (a) by precipitating the 1-chlorophthalazine salt by adding a mineral acid in the presence of solvent and filtering and drying the solid 1-chlorophthalazine salt; c) reacting the isolated and dried 1-chlorophthalazine salt with hydrazine hydrate without any organic solvent and precipitating the hydralazine base by adding a solvent; d) purifying the hydralazine base in a non-aqueous medium; e) converting the purified hydralazine base to hydralazine hydrochloride in a non-aqueous medium and isolating therein; and f) purifying the isolated hydralazine hydrochloride in aqueous medium

Provenance & Evidence