选用密度泛函理论中的B3LYP杂化泛函,在B3LYP/6-31++g(d,p)(C,H,N,S)水平下,优化了2-巯基-5-硝基苯并咪唑分子(MNBMZ)的结构,优化结果表明,2-巯基-5-硝基苯并咪唑分子是一个近平面结构。通过频率计算,获得了2-巯基-5-硝基苯并咪唑分子(M...选用密度泛函理论中的B3LYP杂化泛函,在B3LYP/6-31++g(d,p)(C,H,N,S)水平下,优化了2-巯基-5-硝基苯并咪唑分子(MNBMZ)的结构,优化结果表明,2-巯基-5-硝基苯并咪唑分子是一个近平面结构。通过频率计算,获得了2-巯基-5-硝基苯并咪唑分子(MNBMZ)的拉曼光谱,并和实验获得的拉曼光谱图进行了对比,200~800cm^-1波数段实验获得的拉曼谱带波数和理论计算波数相比,有一定程度的蓝移,800~1800cm^-1波数段实验获得的拉曼谱带波数和理论计算波数相比,发生了一定的红移。对实验和理论计算光谱主要振动峰进行线性回归拟合,相关系数r=0.998,标准偏差14.98。实验和理论计算获得的拉曼光谱图基本上是一致的,表明本文选取的DFT理论计算方法是可靠的。结合VEDA4软件对2-巯基-5-硝基苯并咪唑分子的拉曼谱带简正振动模式进行了指认。此外,分析并讨论了2-巯基-5-硝基苯并咪唑分子(MNBMZ)前线轨道及HOMO,LUMO轨道的组成,HOMO和LUMO轨道能级差为3.31eV,电子有从HOMO跃迁到LUMO的趋势。HOMO轨道中S原子的贡献是52.53%,LUMO轨道中硝基N和O原子的贡献分别为23.03%,19.97%和19.36%。采用含时密度泛函理论(time dependent density functional theory,TDDFT)对2-巯基-5-硝基苯并咪唑分子(MNBMZ)的激发态进行了计算分析,计算结果表明甲醇溶剂中2-巯基-5-硝基苯并咪唑分子(MNBMZ)理论计算的吸收波长为213,281和437nm;实验获得的吸收波长223,272和353nm。对研究2-巯基-5-硝基苯并咪唑分子的性质,提供了理论基础。展开更多
The synthesis process of 2-mercapto-5-methoxyimidazo[4,5-b]pyridine, a crucial intermediate of tenatoprazole which is a new proton pump inhibitor, was studied.2,6-Dichloropyridine as raw material was nitrated by nitri...The synthesis process of 2-mercapto-5-methoxyimidazo[4,5-b]pyridine, a crucial intermediate of tenatoprazole which is a new proton pump inhibitor, was studied.2,6-Dichloropyridine as raw material was nitrated by nitric acid/sulfuric acid, and after amination 2-amino-3-nitro-6-chloropyridine was obtained.It then reacted with sodium methoxide to give 2-amino-3-nitro-6-methoxypyridine and the intermediate was reduced by H2 with Raney Ni as catalyst to give 2,3-diamino-6-methoxypyridine.Finally cyclization was finished with carbon bisulfide to give the title compound.The optimal reaction conditions and yield(temperature, time, molar yield) were as follows: nitration,110℃, 8 h, 79.3%; amination, room temperature, 10 h, 87.6%; methoxylation,65℃, 30min, 98.7%; reduction,70℃, 3 h; cyclization, reflux, 4 h, 72.4% (two steps).The melting point of the title compound was the same as that reported in literature, and its structure was confirmed by 1H NMR.展开更多
文摘选用密度泛函理论中的B3LYP杂化泛函,在B3LYP/6-31++g(d,p)(C,H,N,S)水平下,优化了2-巯基-5-硝基苯并咪唑分子(MNBMZ)的结构,优化结果表明,2-巯基-5-硝基苯并咪唑分子是一个近平面结构。通过频率计算,获得了2-巯基-5-硝基苯并咪唑分子(MNBMZ)的拉曼光谱,并和实验获得的拉曼光谱图进行了对比,200~800cm^-1波数段实验获得的拉曼谱带波数和理论计算波数相比,有一定程度的蓝移,800~1800cm^-1波数段实验获得的拉曼谱带波数和理论计算波数相比,发生了一定的红移。对实验和理论计算光谱主要振动峰进行线性回归拟合,相关系数r=0.998,标准偏差14.98。实验和理论计算获得的拉曼光谱图基本上是一致的,表明本文选取的DFT理论计算方法是可靠的。结合VEDA4软件对2-巯基-5-硝基苯并咪唑分子的拉曼谱带简正振动模式进行了指认。此外,分析并讨论了2-巯基-5-硝基苯并咪唑分子(MNBMZ)前线轨道及HOMO,LUMO轨道的组成,HOMO和LUMO轨道能级差为3.31eV,电子有从HOMO跃迁到LUMO的趋势。HOMO轨道中S原子的贡献是52.53%,LUMO轨道中硝基N和O原子的贡献分别为23.03%,19.97%和19.36%。采用含时密度泛函理论(time dependent density functional theory,TDDFT)对2-巯基-5-硝基苯并咪唑分子(MNBMZ)的激发态进行了计算分析,计算结果表明甲醇溶剂中2-巯基-5-硝基苯并咪唑分子(MNBMZ)理论计算的吸收波长为213,281和437nm;实验获得的吸收波长223,272和353nm。对研究2-巯基-5-硝基苯并咪唑分子的性质,提供了理论基础。
文摘The synthesis process of 2-mercapto-5-methoxyimidazo[4,5-b]pyridine, a crucial intermediate of tenatoprazole which is a new proton pump inhibitor, was studied.2,6-Dichloropyridine as raw material was nitrated by nitric acid/sulfuric acid, and after amination 2-amino-3-nitro-6-chloropyridine was obtained.It then reacted with sodium methoxide to give 2-amino-3-nitro-6-methoxypyridine and the intermediate was reduced by H2 with Raney Ni as catalyst to give 2,3-diamino-6-methoxypyridine.Finally cyclization was finished with carbon bisulfide to give the title compound.The optimal reaction conditions and yield(temperature, time, molar yield) were as follows: nitration,110℃, 8 h, 79.3%; amination, room temperature, 10 h, 87.6%; methoxylation,65℃, 30min, 98.7%; reduction,70℃, 3 h; cyclization, reflux, 4 h, 72.4% (two steps).The melting point of the title compound was the same as that reported in literature, and its structure was confirmed by 1H NMR.
