The present invention relates to novel ultraviolet light absorbers of the benzoxazinone, oxanilide, benzylidene malonate, quinazoline and benzotriazole classes. The invention also relates to polymer and photographic compositions stabilized against the deleterious effects of light induced degradation which comprise the novel ultraviolet light absorbers.
(3 + 3)-Cyclodimerization of Donor–Acceptor Cyclopropanes. Three Routes to Six-Membered Rings
作者:Olga A. Ivanova、Ekaterina M. Budynina、Alexey O. Chagarovskiy、Igor V. Trushkov、Mikhail Ya. Melnikov
DOI:10.1021/jo201612w
日期:2011.11.4
The ability of donor acceptor cyclopropanes to (3 + 3)-cyclodimerize is disclosed. It has been found that Lewis acid-induced transformations of 2-(hetero)arylcyclopropane-1,1-dicarboxylates containing electron-abundant aromatic substituents led to the construction of six-membered cyclic systems. Depending on the substrate properties and the Lewis acid applied, three types of products can be obtained: (1) 1,4-diarylcyclohexanes, (2) 1-aryl-1,2,3,4-tetrahydronaphthalenes, and (3) 9,10-dihydroanthracenes.
[3+2] Cyclodimerization of 2-arylcyclopropane-1,1-diesters. Lewis acid induced reversion of cyclopropane umpolung
作者:Alexey O. Chagarovskiy、Olga A. Ivanova、Ekaterina M. Budynina、Igor V. Trushkov、Mikhail Ya. Melnikov
DOI:10.1016/j.tetlet.2011.06.059
日期:2011.8
A novel Lewis acid catalyzed [3+2] cyclodimerization of 2-arylcyclopropane-1,1-dicarboxylates is reported. It is the first example of a reaction wherein a donor-acceptor cyclopropane provides two carbons in a newly formed ring. The described cyclodimerization represents a general convenient approach to polyfunctionalized cyclopentanes. (C) 2011 Elsevier Ltd. All rights reserved.