The absolute configuration of angular 3′-acyloxypyranocoumarins by vibrational circular dichroism exciton chirality
摘要:
A complex mixture of lomatin C-3' esters and (-)-O-angeloyllomatin 1 was isolated from the seeds of Prionosciadium thapsoides. Since a literature search revealed that some lomatin C-3' monoesters have positive specific rotations, while others had negative values, the absolute configuration of all of the molecules was determined to be (R) by exciton chirality in the infrared region, and by chemical correlation. A single crystal X-ray study of acetyllomatin 3, using the Flack and Hooft parameters, independently confirmed this absolute configuration. (C) 2014 Elsevier Ltd. All rights reserved.
Eight new coumarins were isolated from the fruits of Seseli devenyense Simonkai. Their structures were established from NMR and mass data and their absolute configurations from chemical degradation correlation reactions. The new structures are the decanoic and dodecanoic esters of (+)-lomatin (3, 4), the decanoates of (+)-cis-khellactone at positions 4' (5) and 3' (6) as well as the 2'S epimer of 8-(2
The absolute configuration of angular 3′-acyloxypyranocoumarins by vibrational circular dichroism exciton chirality
作者:Abigail I. Buendía-Trujillo、J. Martín Torrres-Valencia、Pedro Joseph-Nathan、Eleuterio Burgueño-Tapia
DOI:10.1016/j.tetasy.2014.09.001
日期:2014.10
A complex mixture of lomatin C-3' esters and (-)-O-angeloyllomatin 1 was isolated from the seeds of Prionosciadium thapsoides. Since a literature search revealed that some lomatin C-3' monoesters have positive specific rotations, while others had negative values, the absolute configuration of all of the molecules was determined to be (R) by exciton chirality in the infrared region, and by chemical correlation. A single crystal X-ray study of acetyllomatin 3, using the Flack and Hooft parameters, independently confirmed this absolute configuration. (C) 2014 Elsevier Ltd. All rights reserved.