conveniently prepared in moderate or good yields by direct 1,3-dipolarcycloaddition. Isoxazolidines 5-7 derived from fluorinated N-vinyl nucleobases and N-alkyl-methylenenitrones were obtained with complete regiocontrol and stereocontrol and the reactions proceeded with full transfer of the dipolarophile geometry to the cycloadduct. The cycloadditionreactions of N-alkyl-trifluoromethylnitrones with N-vinyl
申请人:King Fahd University of Petroleum and Minerals
公开号:US20160115598A1
公开(公告)日:2016-04-28
Compounds and methods of inhibiting corrosion of mild steel. Compounds disclosed herein are cationic and contain multiple functional motifs such as propargyl, cinnamaldehyde, isoxazolidine and hydrophobe. These compounds are found to be effective in inhibiting mild steel corrosion in HCl, H
2
SO
4
, NaCl and CO
2
-saturated environments.
A series of fused isoxazolidines have been prepared via 1,3-dipolar cycloaddition reactions of N-protected methylenenitrones with 1,3-dimethyluracil derivatives, and their NMR spectra have been recorded in TFA-d and in CDCl3 over a wide range of temperatures. The spectra indicate the presence of two invertomers for all isoxazolidines. Barriers to nitrogen inversion in the cycloadduct 6a have been determined
Chemo-, regio-, and stereoselectivity in 1,3-dipolar cycloaddition of piperine with nitrones. A cycloadditive route to aminoalcohols
作者:Hanna Wójtowicz-Rajchel、Marcin Kaźmierczak
DOI:10.1039/c9nj06442g
日期:——
The chemoselective 1,3-dipolar cycloaddition between piperine and nitrones and further transformation of the cycloadducts to novel acyclic 1,3-amino alcohols.
Formation of cycloadducts with trans-configurated ester groups from nitrones and dimethyl maleate
作者:Hans Günter Aurich、Gerlinde Frenzen、Markus G. Rohr
DOI:10.1016/s0040-4020(01)90471-5
日期:——
there is no clue for either a non-concerted reaction course or a subsequent conversion of the cis-products to trans-product in general. Rather conversion of dimethylmaleate to dimethyl fumarate seems to be responsible for the formation of the trans-substituted cycloadducts. This conversion can be induced by small quantities of N-alkylhydroxylamine formed from slight decomposition of nitrones under the