1H-Pyrazole-1-carboxamidine Hydrochloride

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[4023-02-3] C4H7ClN4 (MW 146.60) InChI = 1S/C4H6N4.ClH/c5-4(6)8-3-1-2-7-8;/h1-3H,(H3,5,6);1H InChIKey = RBZRMBCLZMEYEH-UHFFFAOYSA-N (electrophilic agent capable of specific reaction with nitrogen nucleophiles such as amines and hydrazines, yielding substituted guanidines and aminoguanidines by displacement of pyrazole;1, 2 synthesis of substituted s-triazines1, 3) Alternate Name: 1-guanylpyrazole hydrochloride. Physical Data: mp 167–168 °C. Solubility: insol ether, hexane; very sol H2O, DMF, alcohol; in the presence of 1 equiv Diisopropylethylamine (free base), very sol (>1.5 M) DMF, H2O, and alcohol, and sol CH2Cl2, CHCl3, THF, acetone, and acetonitrile; the free base is slightly sol EtOAc, ether. Form Supplied in: nonhygroscopic, white crystalline solid. Preparative Method: to a mixture of pyrazole (0.36 mol) Cyanamide (0.36 mol), and 320 mL of p-dioxane is added 95 mL of 4 N HCl in p-dioxane. The mixture is gradually warmed to 55–60 °C with mechanical stirring under N2. After about 1 h the product crystallizes and the mixture is cooled to rt. Ether (100 mL) is added with stirring and the product is collected by filtration, washed with ether, and dried in vacuo, yielding 51.2 g (97%). Handling, Storage, and Precautions: indefinitely stable (at least two years) at rt in a tightly sealed bottle. Cool, dry, and dark conditions are recommended for long term storage. The toxicological properties are not known, but pyrazole is considered a possible teratogen. Use in a fume hood.