vary from about 15 minutes to about 1 hour preferably about 30 minutes depending upon the reactants the solvent and the reaction temperature which may vary from about 60 u00b0 c to about 80 u00b0 c preferably around 65 u00b0 c the product is generally worked up by permitting the reaction mixture to cool and then concentrating it in vacuo the resultant residue is recrystallized from an appropriate solvent e g a mixture of a lower alkanol with e g acetone butanone of ethylacetate e g methanol acetone or methanol ethylacetate producing the compound of formula i as its hydrohalide salt treatment with base produces a compound of formula i both the phenacyl halide and the 4 substituted thiosemicarbazide which are employed as starting materials in the preparation of the compounds of formula i are either commercially available or when unavailable are very readily preparable by standard chemical reactions which are well known to those of ordinary skill in the art for example the phenacyl halides may be prepared by halogenating the corresponding methyl optionally substituted phenyl ketone using a sulfuryl halide e g sulfuryl chloride e g in acetic acid e g to prepare the corresponding phenacyl chloride or by reacting the corresponding optionally substituted benzene with a haloacetyl halide e g chloroacetyl chloride via a friedel crafts reaction using an aluminum trichloride catalyst e g to prepare the corresponding phenacyl chloride the 4 substituted thiosemicarbazides.