1H NMR analysis of R-(+)- and S-(−)-α-methoxy-α-trifluoromethylphenyl acetic acid (MTPA) esters of flavan-3-ols and 4-arylflavan-3-ols permits assessment of absolute configurations of C-3 of these condensed tannin structural units.
flavan-3-ols和4-芳基flavan-3-ols的R -(+)-和S -(-)-α-甲氧基-α-三
氟甲基苯基
乙酸(M
TPA)酯的1 H NMR分析这些缩合的
单宁结构单元的C-3中