Kinetics and stereochemistry in the catalytic hydrogenation of acridine
Kinetics and stereochemistry in the catalytic hydrogenation of acridine
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吖啶催化氢化的动力学和立体化学
DOI：
10.1039/p29880001769
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
M. Soeda
中科院分区：
文献类型：
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作者：
K. Sakanishi;M. Ohira;I. Mochida;H. Okazaki;M. Soeda
研究了Pd-Al_2 O_3催化剂催化吖啶（1）加氢反应的动力学和立体化学。一个连续的途径，（1）→ 9，10-二氢吖啶（2）→ 1，2，3，4，4a，9，9a，10-八氢吖啶（5），它与（2）通过1，2，3，从反应时间过程中观察到的产物分布及其动力学模拟，建议4-四氢吖啶（3）或（5）。因此，加氢产物的选择性被发现是由动力学或热力学根据反应条件控制。基于量子化学（MNDO）和分子力学（MM 2）计算，讨论了产物的热力学稳定性，以使反应方案合理化。采用g.c.-i. r.对化合物（5）和全氢吖啶（6）的立体异构体进行了定性和定量分析。和13C n.m.r.立体选择性取决于在较低反应温度（150 °C）下中间体在催化剂表面上的优先吸附;然而，较高温度（250 °C）通过平衡控制产生化学稳定的产物。
Hydrogenation of acridine (1) using a commercial Pd–Al2O3 catalyst was kinetically and stereochemically studied under variable conditions. A consecutive pathway, (1)→ 9,10-dihydroacridine (2)→ 1,2,3,4,4a,9,9a,10-octahydroacridine (5), which competes with hydrogenative isomerization of (2) to 1,2,3,4,5,6,7,8-octahydroacridine (4)via 1,2,3,4-tetrahydroacridine (3) or (5) was suggested from the observed product distributions over the time course of the reactions and their kinetic simulation. Thus, selectivity for the hydrogenated products is found to be controlled by either kinetics or thermodynamics according to the reaction conditions. Thermodynamic stabilities of the products are discussed based on quantum chemical (MNDO) and molecular mechanics (MM2) calculations to rationalize the reaction scheme. The stereoisomers of (5) and perhydroacridine (6) were identified and quantified by detail analyses using g.c.–i.r. and 13C n.m.r. The stereoselectivity is governed by the preference in adsorption of the intermediates on the catalyst surface at a lower reaction temperature (150 °C); however, a higher temperature (250 °C) produces the thermodynamically stable products through equilibrium control.