M. G. Bogdanov, I. Todorov, Pavlina G. Manolova
Nov 1, 2004
Citations
0
Influential Citations
10
Citations
Journal
Tetrahedron Letters
Abstract
The X-ray analysis of 1-oxo-3-thiophen-2-yl-isochroman-4-carboxylic acid methyl ester 1 confirmed its trans-configura- tion and a conformation with diaxial H-3 and H-4 atoms in solid state. NMR experiments indicated that trans-1 exists in solution in both expected conformers. In CDCl3 and especially in CD3OD or DMSO, the conformational equilibrium is shifted towards the conformer with diequatorial H-3 and H-4, which was also determined by 2D NOESY experiments. The shift is due to the greater polarity of that conformer deduced by ab initio calculations. � 2004 Elsevier Ltd. All rights reserved.