Process for preparation of 1-acyl-2-substituted hydrazines

A process for separating a 1-acyl-2-substituted hydrazine compound represented by the formula (1):

• ##STR5## wherein Ar is a phenyl or naphthyl group substituted by 1 to 5 substituents independently selected from the group consisting of hydrogen, halogen, (C.sub.1 -C.sub.6)alkyl, (C.sub.1 -C.sub.6)alkoxy, halo(C.sub.1 -C.sub.6)alkyl and halo(C.sub.1 -C.sub.6)alkoxy, or when two adjacent positions on the phenyl ring are substituted, these groups can form --OCH.sub.2 CH.sub.2 O-- or --OCH.sub.2 CH.sub.2 CH.sub.2 --, and R.sup.1 is a (C.sub.1 -C.sub.6)alkyl group, from a mixture of said hydrazine compound and a 1-acyl-1-substituted hydrazine represented by the formula (2):
• ##STR6## wherein Ar and R.sup.1 are as described above, said process comprising the following steps of:
• deriving a compound represented by the formula (3):
• Ar--COOR.sup.2 ( 3)
• wherein Ar is as described above and R.sup.2 is hydrogen or a (C.sub.1 -C.sub.6)alkyl, from the 1-acyl-1-substituted hydrazine of the formula (2) by selective hydrolysis in the presence of an acid catalyst, or by selective alcoholysis in the presence of an acid catalyst;
• and separating said derived compound represented by the formula (3) from said 1-acyl-2-substituted hydrazine compound represented by the formula (1).