Asymmetric total synthesis of B-ring modified (−)-epicatechin gallate analogues and their modulation of β-lactam resistance in Staphylococcus aureus
摘要:
Two enantiomerically pure B-ring modified analogues of (-)epicatechin gallate were synthesised and their modulation of beta-lactam resistance using three strains of methicillin resistant Staphylococcus aureus (BB 568, EMRSA-15 and EMRSA-16) evaluated. Sub-inhibitory concentrations (12.5 and 25 mg/L) of the two analogues fully sensitised each of the three MRSA strains to oxacillin, reducing the MIC to less than 0.5 mg/L, identical to levels achieved with ECg. Lower concentrations demonstrated that the position and degree of hydroxylation of the B-ring is important for activity. (c) 2005 Elsevier Ltd. All rights reserved.
Total synthesis of mangiferin, homomangiferin, and neomangiferin
作者:Xiong Wei、Danlin Liang、Qing Wang、Xiangbao Meng、Zhongjun Li
DOI:10.1039/c6ob01622g
日期:——
Total synthesis of mangiferin, homomangiferin, and neomangiferin, three C-glycosyl xanthone natural products with a wide spectrum of pharmacological effects, has been achieved starting from 2,3,4,6-tetra-O-benzyl-α/β-D-glucopyranose. The key steps involve a stereoselective Lewis acid promoted C-glycosylation of protected phloroglucinol with tetrabenzylglucopyranosyl acetate and a highly regioselective
An expedient synthesis of enantioenriched substituted (2-benzofuryl)arylcarbinols via tandem Rap–Stoermer and asymmetric transfer hydrogenation reactions
An expedientsynthesis of enantioenriched substituted (benzofuran-yl)-aryl and heteroaryl carbinols, is described. A key feature of this protocol is synthesis of functionally varied benzofuran scaffolds via a Rap–Stoermer reaction/catalytic asymmetric transfer hydrogenation (ATH) using substituted salicylaldehyde and α-haloaryl, heteroaryl ketones.
This paper describes a general method for the synthesis of kehokorins A–E, novel cytotoxic p-terphenyls. 2,4,6-Trihydroxybenzaldehyde served as a common building block for preparation of the central aromatic ring. Construction of their p-terphenyl skeletons was achieved by a stepwise Suzuki–Miyaura coupling, whereas the phenyldibenzofuran moiety was built up by an intramolecular Ullmann reaction. Introduction