三丁基膦与酚类的温和协同催化剂(例如(±)-1,1'-联-2-萘酚(BINOL)在THF中)促进了Baylis-Hillman反应,从而以高收率得到α-亚甲基-β-羟基链烷酮。在有1,1'-联-2-萘酚存在下,该反应进行得比在没有它的情况下进行得快得多。的1项1 H NMR研究表明,1,1'-联-2-萘酚用作布朗斯台德酸来激活醛和偏振烯烃的羰基。通过使用三丁基膦与钙手性催化剂的协同催化剂来检查反应在催化不对称合成中的应用,以相当好的收率得到具有相当好的%ee的所需产物。
Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides
作者:José Brango-Vanegas、Luan A Martinho、Lucinda J Bessa、Andreanne G Vasconcelos、Alexandra Plácido、Alex L Pereira、José R S A Leite、Angelo H L Machado
DOI:10.3762/bjoc.15.247
日期:——
Eight new sulfide-based cyclic peptidomimetic analogues of solonamides A and B have been synthesized via solid-phase peptide synthesis and SN2’ reaction on a Morita–Baylis–Hillman (MBH) residue introduced at the N-terminal of a tetrapeptide. This last step takes advantage of the electrophilic feature of the MBH residue and represents a new cyclization strategy occurring. The analogues were prepared
通过固相肽合成和在四肽N端引入的Morita-Baylis-Hillman(MBH)残基上进行固相肽合成和S N 2'反应,已经合成了8种新的基于磺化物的环酰胺A和B环状拟肽类似物。最后一步利用了MBH残基的亲电子特性,代表了正在发生的新环化策略。这些类似物以中等的总产量制备,对金黄色葡萄球菌的生长没有毒性作用,对人成纤维细胞没有毒性。它们中的两个抑制金黄色葡萄球菌的溶血活性,表明在细菌群体感应中的干扰作用类似于已经报道的对磺胺类药物的干扰作用。
Unprecedented <i>E</i>-stereoselectivity on the sigmatropic Hurd–Claisen rearrangement of Morita–Baylis–Hillman adducts: a joint experimental–theoretical study
作者:Vinicius Sobral Silva、Terezinha Alves Tolentino、Tiago Costa Alves Fontoura Rodrigues、Fernanda Ferrari Martins Santos、Daniel Francisco Scalabrini Machado、Wender Alves Silva、Heibbe Cristhian Benedito de Oliveira、Angelo Henrique Lira Machado
DOI:10.1039/c9ob00533a
日期:——
first systematic investigation of the tandem mercury(II) catalysed transvinylation/Hurd–Claisen rearrangement of MBH adducts derived from alkyl acrylates. This is the first report of E-selectivity for MBH adducts with alkyl side chains and is complementary to the previously reported Johnson–Claisen and Eschenmoser–Claisen rearrangements. The rearrangement products were obtained in good yields and could
This work presents Morita-Baylis-Hillman adducts (MBHA) as new modulators of the violacein biosynthesis in the biosensor strain Chromobacterium CV026. Seven adducts displayed violacein reduction higher than 50±1% when tested at concentrations lower than 625 μM. The most active MBHA inhibited hydrolysis of chitin concomitantly with inhibition of violacein production in CV026, suggesting the disruption
of the QS-regulated operon vioABCDE. Docking calculations suggested a good correlation between binding affinity energies and inhibition effects, with all molecules positioned within the CviR autoinducer-binding domain (AIBD). The most active lactone yielded the best binding affinity energy, most probably due to its unprecedented binding with the AIBD. Our results show α-alkylidene δ-lactones as promising