Absolute configuration of α-phthalimido carboxylic acid derivatives from circular dichroism spectra
摘要:
It is demonstrated that the Cotton effects due to the 220 nm phthalimide pi-pi* transition observed for a series of derivatives of alpha-phthalimidocarboxylic acids unequivocally reflect the amino acid absolute configuration. This method is based on the exciton coupling of the allowed transitions of the phthalimide and the carboxylic acid derivative chromophores. (C) 1999 Elsevier Science Ltd. All rights reserved.
Photochemistry of phthaloylcysteine, its methyl ester and C-unprotected S-alkyl derivatives
作者:Axel G. Griesbeck、Joachim Hirt、Wolfgang Kramer、Paul Dallakian
DOI:10.1016/s0040-4020(98)00063-5
日期:1998.3
cysteine derivatives 1a-d were photochemically transformed by elimination, decarboxylation, and via electron transfer cyclization to the products 2,3,4 and 6–8. The spin selectivities of singlet and triplet pathways were investigated in acetonitrile and acetone. The excited singlets were prone to elimination and γ-H abstractions (e.g. formation of 5) whereas the triplets cyclized to thiazinoisoindoles