Green Approach to Stereoselective Synthesis of Benzo[d]chromeno[3,4- h]oxathiazonine Derivatives via MCRs in Water: A Combined Experimental and DFT Study
作者:Hoorieh Djahaniani、Farzaneh Fatemi、Fatemeh Ektefa、Bita Mohtat、Behrouz Notash
DOI:10.2174/1386207318666150915113230
日期:2015.11.3
(7S, 14S, 16R)- dialkyl 6-oxo-6,7,13,14-tetrahydro-7,14-methanobenzo[d]chromeno[3,4-
h][1,6,3]oxathiazo-nine-14,16-dicarboxylates 4 and (S)-methyl 2-(2-methoxy-2-oxoethyl)-2,3-
dihydrobenzo[d]thiazole-2-carboxylates 5 were readily synthesized in a ratio 3:1 and moderated yield by multicomponent
reactions of 4-hydroxycoumarin and acetylenic esters with benzothiazole without using a catalyst. Also, The GIAO/DFT
approach at the B3LYP/6-31G** level of theory was used to calculate the 1H, 15N, 17O and 13C NMR chemical shifts of
product 4b. These computations are performed on the basis of X-ray structural data which are collected at 120(2) K
temperature. In order to take into account intermolecular hydrogen bonds and the van der Waals effects, two different
sizes of clusters (two model of trimeric and pentameric clusters) have been considered. A comparison between the
experimental (Exp.) and calculated (Cal.) 1H and 13C NMR chemical shifts may reveal that the solution contains
monomer, trimer1, trimer2, and pentamer models.
(7S, 14S, 16R)-二烷基 6-氧代-6,7,13,14-四氢-7,14-亚甲基苯并[d]色烯并[3,4-h][1,6,3]氧杂硫氮杂卓-14,16-二羧酸酯 4 和 (S)-甲基 2-(2-甲氧基-2-氧代乙基)-2,3-二氢苯并[d]噻唑-2-羧酸酯 5 通过多组分反应在无催化剂条件下,以 4-羟基香豆素和炔基酯为原料以3:1的比例和中等的产率轻松合成。此外,GIAO/DFT方法在B3LYP/6-31G**水平上用于计算产物4b的1H、15N、17O和13C核磁共振化学位移。这些计算基于在120(2) K温度下收集的X射线结构数据进行。为了考虑分子间氢键和范德华效应,考虑了两种不同尺寸的簇(三聚体和五聚体模型)。实验(Exp.)和计算(Cal.)的1H和13C核磁共振化学位移的比较可能揭示出溶液中含有单体、三聚体1、三聚体2和五聚体模型。