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POLYFUNCTIONAL PYRAZOLES. 9. SYNTHESIS OF 1-ALKYL(ARYL)-3-[4-(HYDROXYMETHYL)-1H-PYRAZOL-3-YL]UREAS

М. К. Братенко, М. М. Барус, Д. В. Ротар, М. В. Вовк
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Abstract


A convenient method was developed for the synthesis of 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1H-pyrazol-3-yl]ureas based on interaction of 4-hydroxymethylpyrazole-3-carbonyl azides with primary alipfatic or aromatic amines under the Curtius reaction conditions. It was found that in the absence of amines in the reaction medium an intramolecular cyclization of the generated in situ 4-hydroxymethyl-3-isocyanatopyrazoles into pyrazolo[3,4-d][1,3]oxazin-6(4H)-ones takes place. The latter, too, have tendency to turn into 1-alkyl(aryl)-3-[4-(hydroxymethyl)-1H-pyrazol-3-yl]ureas in the presence of amines.

How to Cite
Bratenko, M. K.; Barus, M. M.; Rotar, D. V.; Vovk, M. V. Chem. Heterocycl. Compd. 2014, 50, 1252. [Khim. Geterotsikl. Soedin. 2014, 1359.]

For this article in the English edition see DOI 10.1007/s10593-014-1587-z


Keywords


4-hydroxymethylpyrazole-3-carbonyl azides; (pyrazol-3-yl)ureas; pyrazolo[3,4-d][1,3]oxazines; intramolecular cyclization

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