METHOD OF PREPARING PHENYLHYDRAZINOPYRIDAZINES

Procedure for preparing substituted phenylhydrazinopyridazines, of formula I: **(See formula)** where two of the groups R1, R2 and R3 are hydrogen and the third group is hydrogen, lower alkyl, fluorine, chlorine, bromine, trifluoromethyl, hydroxy, lower alkoxy, lower alkenyloxy, lower alkoxycarbonyl, cyano, -CONH2, -CH2CONH2, nitro, amino, lower alkanoylamino, lower alkylamino or di (lower alkyl) amino; R4 is hydrogen or methyl; R5 is isopropyl, tert-butyl or phenylethyl; characterized in that it comprises the step of treating a compound of formula II: **(See formula)** where R1, R2, R3 and R4 are defined as above and R11 is **(See formula)** where R5 is defined as above, hydrogen or a phenolic protecting group such as ethoxycarbonyl, and Z is mercapto, chloro, alkoxy or phenoxy; with hydrazine or a protected derivative thereof, such as t-butyl carbazate or a hydrazone of an aldehyde or ketone. (Machine-translation by Google Translate, not legally binding)