CHEMICAL TRANSFORMATIONS OF 3-AMINO-5-HYDROXY-4-PHENYLAZO-1H-PYRAZOLE WITH DIFFERENT REAGENTS

Reaction of 3-amino-5-hydroxy-4- phenylazo-1H-pyrazole (1) with phencylbromide, aceticacid anhydride, benzoylchloride, aromatic aldhydes gave the corresponding compounds 2-6, respectively . While, the ring closure for compound 2 in acetic anhydride afforded pyrazolopyrimidine 3 (Scheme1).  Pyrazolopyrimidine derivatives 7,8,9,10 and 12 were obtained by the reaction of 1 with acetylacetone, ethylacetoacetate, ethylcyanoacetate, diethylmalonate and ninhydrine.  Reaction of active methylene group of 10 with aryldiazonium salt gave phenylhydrazinopyrazolopyrimidine 11 (Scheme2). Moreover, reaction of 1 with POcL 3 , P 2 S 5 , phthalic anhydride, chloroacetylchloride, aroylthiocyanate and ammonium thiocyanate gave the corresponding 13, 15, 16, 17 and 18 respectively, as mercapto, chloro and N-substituted.  While, hydrazenolysis of 13 in presence of hydrazine hydrate afforded 14 (Scheme3). pyrazolotriazole 20 and pyrazolothiadiazole 21 were obtained by the reaction of 19 with bromine in different solvent (Scheme4). The newly synthesiszed compounds are elucidated by IR, 1 H-NMR and elemental analysis .