Materials hydrazine monohydrate

To a sample of oxadiazole 76 (1.5 mmol) in dry DMF (2 mL) was added an excess of hydrazine monohydrate (7.5 mmol), and the mixture was stirred at room temperature for 1-10 h. After dilution with water, the mixture was extracted with ethyl acetate, which was then dried with Na2S04. The solvent was removed under reduced pressure, and the resulting crude material was purified by chromatography. Yields of the 1,2,4-triazine 77 ranged from 70-94%. The reaction can be performed in methanol, although longer reaction times are required (48 h) and the yields are reduced (44—88%). 

Materials. N,N-Dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) were stirred over powdered calcium hydride overnight, distilled under reduced pressure, and then stored over 4-A molecular sieves. 4-Aminobenzhydrazide (5) was prepared from methyl 4-aminobenzoate and hydrazine monohydrate according to the reported procedure (6). 4,4 -Thiobisbenzenthiol (6) and isophthalic acid (7) were purified by reciystdlization. Phenyl acrylate and 4-nitrophenyl acetate were prepared by the reactions of acryloyl chloride or acetyl chloride with phenol or 4-nitrophenol in the presence of triethylamine and tetahydrofuran, respectively. TrieAylamine (TEA) and tetahydrofuran (THF) were purified by the usual method. Other reagents and solvents were obtained commercially and used as received. 

Adbel Gawad, M.M., Mahesh, G.V., Patil, K.C., and Bhat, S.V. (1994) An electron spin resonance study of Mn doped calcium hydrazine carboxylate monohydrate. Bulletin of Material Science, 17,1131-1141. 

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