Preparation of 3, 5-disubstituted pyrazoles and isoxazoles from terminal alkynes, aldehydes, hydrazines, and hydroxylamine

R Harigae, K Moriyama, H Togo

Index: Harigae, Ryo; Moriyama, Katsuhiko; Togo, Hideo Journal of Organic Chemistry, 2014 , vol. 79, # 5 p. 2049 - 2058

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Citation Number: 29

Abstract

The reaction of terminal alkynes with n-BuLi, and then with aldehydes, followed by the treatment with molecular iodine, and subsequently hydrazines or hydroxylamine provided the corresponding 3, 5-disubstituted pyrazoles or isoxazoles in good yields with high regioselectivity, through the formations of propargyl secondary alkoxides and α-alkynyl ketones. The present reactions are one-pot preparation of 3, 5-disubstituted pyrazoles ...