الفهرس 
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Abstract
A new series of 4-substituted-1-phenyl-1H-pyrazolo[3,4-d]pyrimidine derivatives have been synthesized with a survey of their biological activities especially the antimicrobial activity.
The starting material of this investigation is ethyl 5-amino-1-phenyl-1H-pyrazole-4-carboxylate (I) which was obtained by reaction of ethyl(ethoxymethylene)-cyanoacetate with phenyl hydrazine . Reaction of compound (III) with either ethyl glycinate hydrochloride or different aryl acid hydrazides afforded the novel compounds; ethyl 2-[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino] -acetate (IV) and N’-(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)-arylhydrazide derivatives (XVa-f) respectively.
In addition, the acid hydrazide (V) was condensed with carbon disulfide and potassium hydroxide to obtain 5-{[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino]methyl}-1,3,4-oxadiazole-2-thiol (IX).
Otherwise, the pyrazole derivative 5-amino-1-{2-[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino]acetyl}-1H-pyrazol-3(2H)-one (X) was obtained by refluxing the acid hydrazide (V) with ethyl cyanoacetate in ethanol.
On the other side, the target; N-phenyl-2-{2-[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino]acetyl}hydrazinecarbothioamide (XI), which was prepared via reacting the acid hydrazide (V) with phenyl isothiocyanate, is an important indermediate for the synthesis of the final compounds; the triazole (XII), the thiadiazole (XIII), the thiazoles (XIVa,b). Cyclization of the thiosemicarbazide derivative (XI) by sodium hydroxides or sulphuric acid affords 4-phenyl-5-{[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino]methyl}-4H-1,2,4-triazole-3-thiol (XII) and N-phenyl-5-{[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino] methyl}-1,3,4-thiadiazol-2-amine (XIII) respectively. Additionally, the thiosemicarbazide (XI) was condensed with phenacyl bromide derivatives to afford N’-[4-(4-substituted-phenyl)-3-phenylthiazol-2(3H)-ylidene]-2-[(1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino] acetohydrazide (XIVa,b).