98664-47-2Relevant academic research and scientific papers
Cycloadditions of N-Aryl-C-(Trifluoromethyl)nitrilimines with Dimethyl Fumarate and Maleate
Tanaka, Kiyoshi,Maeno, Seiji,Mitsuhashi, Keiryo
, p. 565 - 568 (2007/10/02)
The cycloadditions of N-aryl-C-(trifluoromethyl)nitrilimines 1, generated in situ from various precursors, with dimethyl fumarate and maleate are described.N-Aryltrifluoroacetohydrazonoyl bromides 2 reacted with fumarate in the presence of triethylamine to give the trans-4,5-dimethoxycarbonylpyrazolines 4 whereas the reactions with maleate afforded the 4,5-dimethoxycarbonylpyrazoles 5 as well as 4.In the reactions with the chloride 6 under the more drastic conditions, both fumarate and maleate gave the pyrazole 5a.From thermolysis of the oxadiazaphosphole 8, thetrans-pyrazoline 4a was formed in both cases of fumarate and maleate.The preparation of the cis-pyrazoline 9 was attempted from 8 and maleic anhydride but 9 was found to be so unstable as to be epimerized under the mild conditions.
