Synthesis and Self-Assembled Helical Supramolecular Polymer of Ethyl 7,8-dihydro-3-hydroxy-9-methyl-7-(4′-nitrophenyl)-6<i>H</i>-dibenzo[<i>c</i>]- pyran-6-one-8-carboxylate
作者:Chaoyue Chen、Jinsong Hu、Xiaomei Zhang、Jianjun Shi、Jie He
DOI:10.1002/hc.21133
日期:2014.1
of tandem Pechmann–dehydration between diethyl 4-hydroxy-4-methyl-2-(4′-nitrophenyl)-6-oxocyclohexane-1,3-dicarboxylate (1) and resorcinol in the presence of trifluoroacetic acid. The structure of the product was determined as a racemate of (7R,8R)- and (7S,8S)-ethyl 7,8-dihydro-3-hydroxy-9-methyl-7-(4′-nitrophenyl)-6H-dibenzo[c]-pyran-6-one-8-carboxylate (3a) enantiomers by single crystal X-ray diffraction
分离出一种结构新颖的化合物,它是 4-羟基-4-甲基-2-(4'-硝基苯基)-6-氧代环己烷-1,3-二羧酸二乙酯 (1) 和间苯二酚之间串联 Pechmann 脱水的主要产物。三氟乙酸的存在。产物的结构被确定为(7R,8R)-和(7S,8S)-乙基7,8-二氢-3-羟基-9-甲基-7-(4'-硝基苯基)-6H-的外消旋物dibenzo[c]-pyran-6-one-8-carboxylate (3a) 对映异构体通过单晶 X 射线衍射分析。X 射线晶体结构表明,由于 Pechmann 缩合产物 2 分子内脱水行为的立体选择性,3a 具有扩展且更稳定的共轭芳烃系统。在晶体超结构中,(7R,8R)-和 (7S,