紫杉烷类微管稳定剂是最有效和最广泛使用的化疗药物之一。紫杉烷类的抗癌活性源于其通过选择性识别未组装微管蛋白中的弯曲(c-)构象(与组装微管蛋白中的直(s-)构象相比)来诱导微管蛋白组装的能力。我们首先设计并合成了一系列带有共价基团的3'N修饰的紫杉烷。我们没有发现共价紫杉烷,而是发现了一系列非共价紫杉烷2 ,其中 3'N 侧链由于其将微管蛋白锁定在 s 构象中的作用而被发现对于细胞毒性至关重要。带有丙烯酰胺部分的代表性化合物 ( 2h ) 与紫杉醇相比,对未组装的微管蛋白 c 构象具有更高的结合亲和力,并且细胞毒性更低。对2h左右化学空间的进一步探索提供了新的系列3,其中与紫杉醇相比, 3l等衍生物与微管蛋白的 s 和 c 构象结合更紧密,从而更有效地促进微管蛋白聚合,并具有更大的持久性。药物洗脱后对乳腺癌细胞的体外功效。尽管与紫杉醇相比,3l也具有改善的体内效力,但它也与增加的全身毒性有
2-Benzyl-2-methylsuccinic acid as inhibitor for carboxypeptidase A. synthesis and evaluation
摘要:
Recently, Asante-Appiah et al. (Asante-Appiah, E.; Seetharaman, J.; Sicheri, F.; Yang, D. S.-C.; Chan, W. W.-C. Biochemistry 1997, 36, 8710-8715) reported that 2-ethyl-2-methylsuccinic acid isa highly potent inhibitor for carboxypeptidase A (CPA), a prototypic zinc protease. The X-ray crystal structure of the complex of the enzyme formed with 2-ethyl-2-methylsuccinic acid revealed that at the active site of CPA there is present a small cavity which accommodates the methyl group of the inhibitor. These investigators postulated that incorporation of a methyl group at the alpha-position to the carboxylate of existing inhibitors of CPA would improve the inhibitory potency. We have synthesized racemic and optically active 2-benzyl-2-methylsuccinic acids and evaluated their inhibitory activities for CPA to find the K-i values to be 0.28, 0.15, and 17 mu M for racemic form, (R)-, and (S)-enantiomer, respectively. Contrary to the expectation, the effect on the binding affinity by the incorporation of the methyl group is minimal. The validity of the proposition that the small cavity may be utilized for the improvement of the inhibitory potency appears questionable. (C) 1999 Elsevier Science Ltd. All rights reserved.
Asymmetric hydrogenation of prochiral carboxylic acids and functionalized carbonyl compounds catalysed by ruthenium(II)-binap complexes with aryl nitriles (binap = (R)- or (S)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl)
Complexes RuCl2(ArCN)2(binap), II (binap = (R)- or (S)-2,2′-bis(diphenylphosphino)- 1,1′-binaphthyl; ArCN = benzonitrile, a; 2-furancarbonitrile, b; pentafluorobenzonitrile, c) were prepared, and their solution properties were investigated by 31P NMR measurements. The catalytic activities and enantioselectivities for IIa–c catalysedhydrogenation of some prochiral acids were very similar to those provided
作者:Isuru Dissanayake、Jacob D. Hart、Emma C. Becroft、Christopher J. Sumby、Christopher G. Newton
DOI:10.1021/jacs.0c06306
日期:2020.8.5
5-Bis(tert-butyldimethylsilyloxy)furans are established as vicinal bisketene equivalents for application as dienes in the Diels-Alderreaction. Cycloaddition with olefinic dienophiles, under exceptionally mild conditions, enables convergent access to highly substituted para-hydroquinones in unprotected form via a one-pot Diels-Alder/ring-opening/tautomerization sequence. The synthesis of para-benzoquinones from
Asymmetric synthesis of (R)- and (S)-4-(substituted benzyl)dihydrofuran-2(3H)-ones: an application of the ruthenium-binap complex-catalysed asymmetric hydrogenation of alkylidenesuccinic acids
A concise synthesis of (S)- or (R)-4-(substituted benzyl)dihydrofuran-2(3H)-ones (1) with high enantiomeric purity is presented. (S)- or (R)-(Substituted benzyl)succinic acids (6) 97% enantiomeric excess) were first prepared by Ru2Cl4[(R)- or (S)-binap)]2(NEt3) catalysed asymmetrichydrogenation of (substituted benzylidene)succinic acids. The diacids (6) were converted into (R)- or (S)-2-(substituted
Topically applicable cosmetic/dermatological compositions useful for treating dandruff and/or squamae of the human scalp contain at least one anti-fungal agent selected from the group consisting of pyridinethione salts, 1-hydroxy-2-pyrrolidone compounds, 2,2′-dithiobis(pyridine N-oxide) and selenium sulfides, and mixtures thereof, and at least one wholly hydrophilic block copolymer which comprises at least one polyionic block, formulated into a topically applicable, physiologically acceptable medium therefor.