Determination of absolute configuration of photo‐degraded catechinopyranocyanidin A by modified Mosher's method
| Autor: | Tadao Kondo, Toshimichi Shimizu, Kin-ichi Oyama, Kumi Yoshida |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
(+)‐catechin
Alcohol 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis Analytical Chemistry diazomethane photo‐degraded catechinopyranocyanidins A and B Pigment chemistry.chemical_compound Residue (chemistry) anisotoropic effect Drug Discovery Spectroscopy Pharmacology 010405 organic chemistry Chemistry Diazomethane Organic Chemistry Absolute configuration modified Mosher's method Catechin catechinopyranocyanidins A and B 0104 chemical sciences NMR spectra database absolute configuration visual_art (−)‐epicatechin visual_art.visual_art_medium Chirality (chemistry) |
| Zdroj: | Chirality. 32(5):556-563 |
| ISSN: | 0899-0042 |
| Popis: | Catechinopyranocyanidins A and B (cpcA and cpcB) are two purple pigments present in the seed‐coat of red adzuki bean, Vigna angularis , of which cpcA is the major pigment, containing two chiral carbons in the catechin part. Their absolute configurations were determined by comparison of their experimental and quantum chemical calculated electronic circular dichroisms (ECDs). These purple pigments are labile on light irradiation and easily decompose to photo‐degraded catechinopyranocyanidins A and B (pdcpcA and pdcpcB), while retaining the stereostructure of the catechin residue. We applied modified Mosher's method for determining the chirality of the secondary alcohol in pdcpcA. Hexamethylation of pdcpcA by diazomethane followed by esterification using (S )‐ and (R )‐MTPACl gave (R )‐ and (S )‐MTPA esters, respectively. By analysis of the NMR spectra of (R )‐ and (S )‐MTPA esters of tetramethylated (+)‐catechin, the chirality of pdcpcA was determined to be 2R , 3S , same as the absolute configuration of cpcA. ファイル公開：2021-05-01 |
| Databáze: | OpenAIRE |
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