Rearrangements of 3H-Pyrazoles—Adducts of Dimethyl Acetylenedicarboxylate with Diphenyldiazomethane and 9-Diazofluorene


如何引用文章

全文:

开放存取 开放存取
受限制的访问 ##reader.subscriptionAccessGranted##
受限制的访问 订阅存取

详细

Structurally related 3H-pyrazoles resulting from 1,3-dipolar cycloaddition of diphenyldiazomethane and 9-diazofluorene to dimethyl acetylenedicarboxylate undergo van Alphen–Hüttel rearrangement on heating in a polar solvent (methanol, ethanol, acetic acid). In the first case, the rearrangement involves strictly regioselective 1,5-phenyl migration toward the carbon atom with the formation of relatively stable 4H-pyrazole. Post-rearrangement of the product on heating at 180°C in toluene gives a mixture of methyl 1H-pyrazole-1-carboxylates via successive migrations of the CO2Me group. In the second case, the aryl substituent concurrently migrates both to nitrogen atom with the formation of 1H-pyrazole structure (phenanthridine derivative) and to carbon atom with subsequent rearrangement of unstable 4H-pyrazole to 3H-pyrazole fused to phenanthrene fragment. Heating of dimethyl acetylenedicarboxylate adducts (3H-pyrazoles) in an aprotic solvent (benzene, toluene) leads to the corresponding denitrogenation products. This process is especially facile for the spirocyclic 3H-pyrazole derived from 9-diazofluorene, and it yields cyclopropene derivative. Some previous errors in the structure determination of the rearrangement products have been corrected.

作者简介

V. Vasin

Ogarev Mordovian State University

Email: tadaakiyattsu@gmail.com
俄罗斯联邦, ul. Bol’shevistskaya 68, Saransk, 430005

V. Razin

St. Petersburg State University

Email: tadaakiyattsu@gmail.com
俄罗斯联邦, Universitetskii pr. 26, St. Petersburg, 198504

E. Bezrukova

Ogarev Mordovian State University

编辑信件的主要联系方式.
Email: tadaakiyattsu@gmail.com
俄罗斯联邦, ul. Bol’shevistskaya 68, Saransk, 430005

Yu. Popkova

Ogarev Mordovian State University

Email: tadaakiyattsu@gmail.com
俄罗斯联邦, ul. Bol’shevistskaya 68, Saransk, 430005

N. Somov

Lobachevskii Nizhny Novgorod State University

Email: tadaakiyattsu@gmail.com
俄罗斯联邦, pr. Gagarina 23, Nizhny Novgorod, 603950

补充文件

附件文件
动作
1. JATS XML

版权所有 © Pleiades Publishing, Ltd., 2018