The hydroxyl stretching frequencies and conformations of Flavan-4-ols and Thiaflavan-4-ols
GF Katekar and AG Moritz
Australian Journal of Chemistry
22(11) 2337 - 2342
Published: 1969
Abstract
The hydroxyl stretching frequencies of some 2,4-cis and 2,4-trans flavan-4-ols, thiaflavan-4-ols, and related compounds have been measured in dilute carbon tetrachloride solution. Characteristic frequencies are observed at 3626±2 cm-1 (free hydroxyl), 3616±1, and 3597±2 cm-1. The 3616 and 3597 cm-1 bands are assigned to pseudo-axial and pseudo-equatorial hydroxyl groups respectively. Evidence is presented to show that the frequency shifts arise from differences in the interaction of the hydroxyl group with the π-electrons of the fused benzene ring, and that these flavans and thiaflavans exist in half- chair, rather than sofa conformations.https://doi.org/10.1071/CH9692337
© CSIRO 1969