The cycloaddition of nitrilimines with 1,2-dibenzoylethylenes gave an unexpected 1,3-diaryl-4-benzoylpyrazole and benzoic acid, along with an expected cycloadduct, 1,3-diaryl-4,5-dibenzoyl-2-pyrazoline, and its dehydrogenated product, 1,3-diaryl-4,5-dibenzoylpyrazole. The elimination of the benzoyl group from the pyrazoline followed by dehydrogenation was shown to be the course of the unusual reaction
Facile synthesis of hydrazonyl halides by reaction of hydrazones with N-halosuccinimide-dimethyl sulfide complex
作者:Himatkumar V. Patel、Kavita A. Vyas、Sudhanshu P. Pandey、Peter S. Fernandes
DOI:10.1016/0040-4020(95)00916-7
日期:1996.1
new and convenient method is described for the synthesis of hydrazonylhalides. Hydrazones on treatment with N-chlorosuccinimide-dimethyl sulfidecomplex result in the formation of the corresponding hydrazonyl chlorides in good yields. Similarly, treatment of hydrazones with N-bromosuccinimide-dimethyl sulfidecomplex gives the corresponding hydrazonyl bromide under extremely mild conditions.
Reactions of Thioamides and Selenoamides with Hydrazonoyl Chlorides Under Phase-Transfer Conditions. A Convenient Method of Preparation of δ<sup>2</sup>-1,3,4-Thiadiazolines and δ<sup>2</sup>-1,3,4-Selenadiazolines
作者:M. L. Petrov、M. A. Abramov
DOI:10.1080/10426509808545473
日期:1998.2.1
Reactions of enolizable thio- and selenoamides with hydrazonoyl chlorides in the presence of bases and phase-transfer catalysts result in 2-dialkylamino-Δ2-1,3,4-thia- and selenadiazolines. The reactions proceed through formation of corresponding enethiolates and eneselenolates. At 80°C 2-dialkylamino-Δ2-1,3,4-thia- and selenadiazolines eliminate dialkylamines, giving 2-ylidene-Δ2-1,3,4-thia- and selenadiazolines
The reaction of 2H-1-benzopyran with several 1,3-dipoles gives cycloadducts in good yields. The orientation of the cycloaddition is qualitatively interpreted in terms of FMO theory. These heteropolycyclic compounds were also obtained from hydrazones of 3-aroyl-2H-1-benzopyrans, prepared from 3-cyano-2H-1-benzopyran.
A Library Synthesis of Pyrazoles by Azomethine Imine Cycloaddition to the Polymer-supported Vinylsulfone
作者:Nobuhiro Fuchi、Takayuki Doi、Takashi Takahashi
DOI:10.1246/cl.2005.438
日期:2005.3
1,3-Dipolar cycloaddition of azomethine imines to the polymer-supported vinylsulfone was achieved. Pyrazole derivatives bearing various aryl groups were synthesized regioselectively.