| abstract |
NEW MATERIAL:A compound expressed by formula I (R1 is cycloalkyl, alkyl, aryl or heterocyclic group; X is H, halogen, cyano, alkoxycarbonyl, aryloxycarbonyl or carboxyl; A is protonic acid; n is 0 or a positive integer). EXAMPLE:3-Ethoxy-4-ethoxycarbonyl-5-hydrazinopyrazole. USE:An intermediate for photographic couplers. PREPARATION:A 5-amino-1H-pyrazole derivative expressed by formula II is diazotized with a diazotizing agent, e.g. sodium nitrite, in the presence of hydrochloric acid, etc., and the resultant product is then reduced with sodium hydrosulfite, etc., to afford the aimed substance. |