Stereoselective synthesis of optically active bicyclic β-lactam carboxylic acids that target pilus biogenesis in pathogenic bacteriaElectronic supplementary information (ESI) available: 13C NMR spectra of 7(a–g), 10–14, 16(a and d) and 17(a–b). See http://www.rsc.org/suppdata/ob/b2/b210551a/
作者:Hans Emtenäs、Marcus Carlsson、Jerome S. Pinkner、Scott J. Hultgren、Fredrik Almqvist
DOI:10.1039/b210551a
日期:2003.4.14
Optically active bicyclic β-lactams were synthesized, starting from 2-H-Î2-thiazolines and Meldrum's acid derivatives. Several methods to accomplish an ester hydrolysis without damaging the β-lactam framework were investigated. A rapid CsOH saponification of the β-lactam methyl esters was developed and protonation of the Cs-carboxylates by Amberlite (IR-120 H+) afforded a series of bicyclic β-lactam carboxylic acids. Moreover, a convenient method for the synthesis of 2-H-Î2-thiazolinecarboxylic acid methyl ester 2 was developed. Bicyclic β-lactam carboxylic acids 7aâg and aldehydes 4aâd were screened for their affinity to the bacterial periplasmic chaperone PapD using a surface plasmon resonance technique. β-Lactams substituted with large acyl substituents showed better binding to the chaperone than the native C-terminal peptide PapG 8, demonstrating that bicyclic β-lactams constitute a new class of potential bacterial chaperone inhibitors.
从 2-H-Î2-thiazolines 和 Meldrum 酸衍生物开始,合成了具有光学活性的双环 β 内酰胺。研究了几种在不破坏δ-内酰胺框架的情况下完成酯水解的方法。我们开发出了δ-内酰胺甲酯的 CsOH 快速皂化法,并通过 Amberlite(IR-120 H+)对 Cs-羧酸盐进行质子化,得到了一系列双环δ-内酰胺羧酸。此外,还开发出了一种合成 2-H-Î2-thiazoline 羧酸甲酯 2 的简便方法。利用表面等离子体共振技术筛选了双环δ-内酰胺羧酸 7aâg 和醛 4aâd,以确定它们与细菌外质伴侣 PapD 的亲和力。与原生 C 端肽 PapG 8 相比,被大酰基取代的δ-内酰胺与该伴侣的结合效果更好,这表明双环δ-内酰胺构成了一类新的潜在细菌伴侣抑制剂。