An alternative method of producing the 1,2-diethyl-4aminopyrazolidine (VIII) is by reduction of the corresponding nitro compound (VII), which is derived from 1,3-dimorpholino-2-nitropropane (VI) and 1,2-diethylhydrazine (II).
Dazopride can be prepared by the condensation of the 1,2-diethyl-4-aminopyrazolidine (VIII) with either 4-amino-5-chloro-2-methoxybenzoic acid in the presence of phosphorus trichloride-pyridine or the corresponding mixed anhydride (IX).
The dialkylation of aqueous N,N'-diacetyl-hydrazine by simultaneous addition of diethyl sulfate and potassium hydroxide so as to maintain a pH of 10.5-11.5 affords N,N'-diacetyl-N,N'-diethylhydrazine, which is hydrolyzed to diethylhydrazine (II) by hydrochloric acid. The pH of the acid solution is adjusted to 10, where it is maintained during the addition of epichlorohydrin to give 1,2-diethyl-4-pyrazolidinol (III). The pyrazolidinol is converted to 1,2-diethyl 4-aminopyrazolidine (VIII) by either amination of the corresponding chloro compound (IV) or displacement of the mesyloxy group in compound (V) by the azide ion, followed by reduction.