Generation of simple enols by photooxidation. Keto-enol equilibrium constants of some aliphatic systems in aqueous solution
作者:J. R. Keeffe、A. J. Kresge、N. P. Schepp
DOI:10.1021/ja00214a069
日期:1988.3
polarities, can be used as a guide to the solvation of the geminate pair. A constant energy difference of 0.345 f 0.013 eV is found in the emission of exciplexes of DCA with the two-ring compounds 1-3 in acetonitrile and cyclohexane. For the corresponding exciplexes of the one-ring donors in these two solvents, a constant and higher value of 0.49 f 0.02 eV is found, which is consistent with higher
定性地说,与单环供体 11a*b 相比,双环供体的较小 V 表明轨道重叠积分较小,并且与较大芳族系统的分子轨道的更复杂节点结构导致更小的基质元素的预测一致。 'Ic 对于单环化合物,较大的 A 表明与双环化合物相比,这些双环化合物的溶剂化程度更高。从 exciplex 发射数据中获得了对该建议的支持。尽管激基复合物的溶剂化程度不如双生对,但这些物质可以被认为是溶剂渗透双生对的接触离子对等价物。 '2 因此,从不同极性溶剂中发射最大值的差异获得的激基复合物溶剂化,可用作双子对溶剂化的指南。在乙腈和环己烷中 DCA 与双环化合物 1-3 的激发态发射中发现了 0.345 f 0.013 eV 的恒定能量差。对于这两种溶剂中单环供体的相应激基复合物,发现了 0.49 f 0.02 eV 的恒定且更高的值,这与这些情况下的较高溶剂化一致。这些系统中的返回电子转移率 k,,, 显然对小的结构变化非常
Concerted catalysis in the enolisation of aldehydes
作者:Anthony F. Hegarty、Joe Dowling
DOI:10.1039/c39910000996
日期:——
At high buffer concentrations the enolisation of aldehydes is markedly catalysed simultaneously by acidic and basic species; the magnitude of the ‘third-order term’ can be related directly to the importance of the individual acid and base catalysed terms.
A simple procedure for the synthesis of 3-(substituted-sulfanyl)-4-hydroxy-6-substituted-pyran-2-ones
作者:K. S. Para、E. L. Ellsworth、J. V. N. Vara Prasad
DOI:10.1002/jhet.5570310657
日期:1994.11
A series of 3-(substituted sulfanyl)-4-hydroxy-6-substituted-pyran-2-ones were synthesized for Human immunodeficiency virus-1 protease inhibition. These compounds were synthesized in a simple and convergent fashion to allow us a rapid preparation of many structurally diversified analogues. Thus the condensation of trimethylsilyl enol ethers of corresponding ketones, with 2-(S-substituted)propane-1
Bis-(2-cyclopentenyl) ethers are prepared by contacting a 2-cyclopentenyl carboxylate or 2-cyclopentenol with an aqueous acid solution having a pH in the range of about 1.0 to about 3.0.
The present invention comprises 6-9-Disubstituted 2-[trans-(4-aminocyclohexyl]aminopurines that are useful in inhibiting cyclin dependent kinases, particularly cdk-2. The present invention also provides a method of preventing apoptosis in neuronal cells and a method of inhibiting the development of neoplasms.