Patent ID: 7625935

Claim:
A process for the preparation of a high purity butoconazole nitrate salt of the formula (I) comprising the steps of: a) reacting 1-chloro-4-chlorophenyl-2-butanol with imidazole in a mixture of a water immiscible solvent and an aqueous solution of alkali metal hydroxide or carbonate in the presence of a phase transfer catalyst to yield a compound of the Formula IV (b) reacting the compound formula of the (IV) obtained in step a), with thionyl chloride in 1,2-dichloroethane as a solvent in the presence of dimethylformamide, whereas 1-1.2 mol of thionyl chloride reagent is used based on the amount of the compound of the formula (IV) to yield a compound of the formula (V) and (c) reacting the compound of the formula (V) obtained in step b), with 2,6-dichlorothiophenol to obtain the compound of the Formula (VI) and without isolation of the compound of the Formula (VI), which remains in solution, adding nitric acid and isolating as a product the butoconazole nitrate salt of the Formula (I) having a maximum 0.1 wt % of chemical impurities.