ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A concise route to 4-aminomethylpyrazoles and 4-aminomethylisoxazoles from acetylacetone-derived hexahydropyrimidines under mild conditions

Abdullah I. Saleh, Kayed A. Abu-Safieh, and Bader A. Salameh

Department of Chemistry, Hashemite University, Zarqa 13115, Jordan

E-mail: a-saleh@hu.edu.jo

Abstract: Acetylacetone was successfully used as a precursor of 4-aminomethylpyrazoles and 4-aminomethylisoxazoles in a two step process at ambient temperature. In the first step, acetylacetone was transformed to the corresponding hexahydropyrimidines (1,3-diazinanes) via two consecutive one-pot Mannich aminomethylations. Hexahydropyrimidines were then treated with hydrazine, phenylhydrazine, and hydroxylamine, respectively, to obtain the corresponding 4-aminomethylpyrazoles and 4-aminomethylisoxazoles in good yields. The hexahydropyrimidine ring decomposed providing the title compounds and a reasonable mechanism has been proposed.

Keywords: 4-aminomethylpyrazoles – 4-aminomethylisoxazoles – hexahydropyrimidines – 1,3-diazinanes – pyrazolone – aminomethylations – geminal diamines

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0018

Chemical Papers 69 (5) 729–736 (2015)