No abstract

5-Aryl-2-phenylpyrazolo[1,5-c]pyrimidine-7(6H)-thiones have been synthesized by the reaction of 1,5-diaryl-4-pentyne-1,3-diones with thiosemicarbazide and their reactions were studied. The pyrazolopyrimidinethiones give with certain electrophiles the respective 3-substituted 7-thiones. Their oxidation affords the corresponding disulfide. Moreover, they can be converted to the corresponding pyrazolopyrimidinones on reaction with alkaline hydrogen peroxide. The structure of the above compounds was confirmed from their spectral characteristics.

A simple method for the synthesis of acetylenic β‐diketones is described. They can be cyclized to the corresponding 4H‐pyran‐4‐ones with acids. Their reaction with hydrazine hydrate gave pyrazole derivatives isomeric with those obtained from 4H‐pyran‐4‐ones. With hydroxyl‐amine hydrochloride in ethanol, 1‐hydroxy‐4‐pyridones are formed.

Thermal cyclization of 1,5‐diarylpent‐1‐yne‐3,5‐diones led to the formation of 2‐benzyliden‐5‐aryl‐3(2H) furanones as well as 2,6‐diaryl‐4H‐pyran‐4‐ones as minor products. The structure of the furanones was established from their ir, 1H nmr and mass spectral data. Their reaction with hydrazine hydrate gave pyrazole derivatives.

Pyrone Series. Part X1.l Reactivity of 4,6-Diaryl-Z-pyrones and Cyclopropane Derivatives obtained from 2-Pyrazolines By lbrahim El-Sayed EI-Kholy," Fathi Kame1 Rafla, and Morcos. Michael Mishrikey, Chemistry Depart-4.6-Diaryl-2-pyrones and ethyl 2-aroyl-3-arylcyclopropanecarboxylates have been prepared from 2-pyrazolines.The structure of the pyrones was established by fission with alkali, Treatment of the cyclopropane derivatives with hydrazine hydrate gave diazabicycloheptenones, from which N-acetyl and N-methyl derivatives were prepared. The 2-pyrazolines were also converted into pyrazine derivatives (111). which gave N-oxides. The pyrones could b e converted in to 2pyridones, 1 -methyl -2-pyridones, 2methoxypyri di nes, 1 -ami no-2-pyridon es, 2thiopyro nes, 1 -methyl-2-thiopyridones, and 1 -thio-2-pyrones. The structures assigned to the products were established by U.V. and i.r. spectroscopy.