SYNTHESIS AND REACTION OF NEW PYRAZOLE DERIVATIVES

N-(4-(2-phenyldiazenyl)-2,5-dihydro-3-hydroxy-1H-pyrazol-5-yl)-2 chloroacetamide 2 was obtained from reaction of 3-amino-5-hydroxy -4- phenylazo-1H-pyrazole 1  with chloroacetylchloride . Reaction of 2 with malononitrile and ammoniumisothiocyanate gave the corresponding 1-(4-(2-phenyldiazenyl)-5-hydroxy-1H-pyrazol-3-yl)-2-amino-4,5-dihydro-5-oxo-1H-pyrrol-3-carbonitrile 3 and 3-(2-phenyldiazenyl)-7-amino-2-hydroxy pyrazolo[1,5-a] pyrimidin-5(1H)-one 4. Thiation of 1 with P2S5 gave the corresponding 3-amino-5-mercapto-4-phenylazo-1H-pyrazole 5. The reaction of compound 5 with chloroaceticacid, ethylchloroacetate, tetrahydrofuran, 3-hydroxybenzaldhyde, phencylbromide and ninhydrine  gave the corresponding 6,7,8,9,10,11,12,13 respectively, as mercapto, N-substituted. While, hydrazenolysis of7 inthe presence of hydrazine hydrate afforded 8 and cyclization of11 in  the presence aglacial acid and sulfuric acid mixture  afforded 12. 1-(4-(2-phenyldiazenyl)-5-mercapto-1H-pyrazol-3-yl)-3- phenylthiourea 14 was obtained from reaction of 5 with phenyl isothiocyanate. pyrazolothiadiazole 15 and pyrazolotriazole 16 were obtained by the reaction of 14 with bromine in different solvents. 3-amino-5-hydrazino-4-phenylazo-1H-pyrazole 17 was obtained from reaction 5 with hydrazine hydrate. Cyclization of compound 17 by reacting it with ethylacetoacetate, acetylacetone, phthalic anhydride and phencylbromide gave the corresponding N-pyrazolylpyrazole derivatives 18 & 19, pyrazol-2,3-dihydrophthalazine-1,4-dione 20 and pyrazolotriazine 21, respectively. Reaction of 17 with sodium nitrate in the presence acetic acid, ethyl pyruvate and carbon disulfide gave the corresponding pyrazolotetrazole 22, imidazolopyrazole 23 and pyrazolotriazole derivatives 26. hydrazenolysis of 17 in the presence of hydrazine hydrate afforded 24 and cyclization it in  the presence aglacial acid and sulfuric acid mixture  afforded 25.