描述了四种新的天然存在的远程功能化次级霉菌代谢物酸酐 lad 的首次合成,从 Np-甲苯基柠康酰亚胺 (5) 开始,分三到六步,总产率为 20-65%。三苯基膦-马来酰亚胺加合物 6 与醛 4 的缩合提供了外酰亚胺 7,其在异构化、水解和酰化后在四个步骤中以 54% 的总产率得到曲霉酸 A (Ia)。加合物6与醛15的缩合类似地在两个步骤中提供了所需的酰亚胺17。酰亚胺 17 的酸催化水解直接提供曲霉酸 B (1b),暴露出作为末端乙炔存在的潜在甲基酮。硼氢化钠诱导曲霉酸 B (1b) 的化学选择性还原产生曲霉酸 C (1c),在乙酸酐诱导的酰化作用下,提供曲霉酸 D (1d)。曲霉酸 C (1c) 的简便 Amano PS 催化酰化以良好的收率得到所需的 (+)-曲霉酸 C (1e) 在 70% ee 中和 (-)-曲霉酸 D (If) 在 72% ee . 在目前的酶促反应中,酸酐部分
A Facile Synthesis and Enzymatic Resolution of Naturally Occurring Remotely Functionalized Alkylmethylmaleic Anhydrides from<i>Aspergillus wentii</i>: Aspergillus Acids A-D
作者:Narshinha P. Argade、Srinivasan Easwar
DOI:10.1055/s-2006-926326
日期:——
The first synthesis of four new naturallyoccurring remotely functionalized secondary mould metabolite anhydrides lad is described starting from N-p-tolyl citraconimide (5) in three to six steps and 20-65% overall yields. The condensation of triphenylphosphine-maleimide adduct 6 with aldehyde 4 furnished the exoimide 7, which after isomerization, hydrolysis, and acylation gave aspergillus acid A (la)
描述了四种新的天然存在的远程功能化次级霉菌代谢物酸酐 lad 的首次合成,从 Np-甲苯基柠康酰亚胺 (5) 开始,分三到六步,总产率为 20-65%。三苯基膦-马来酰亚胺加合物 6 与醛 4 的缩合提供了外酰亚胺 7,其在异构化、水解和酰化后在四个步骤中以 54% 的总产率得到曲霉酸 A (Ia)。加合物6与醛15的缩合类似地在两个步骤中提供了所需的酰亚胺17。酰亚胺 17 的酸催化水解直接提供曲霉酸 B (1b),暴露出作为末端乙炔存在的潜在甲基酮。硼氢化钠诱导曲霉酸 B (1b) 的化学选择性还原产生曲霉酸 C (1c),在乙酸酐诱导的酰化作用下,提供曲霉酸 D (1d)。曲霉酸 C (1c) 的简便 Amano PS 催化酰化以良好的收率得到所需的 (+)-曲霉酸 C (1e) 在 70% ee 中和 (-)-曲霉酸 D (If) 在 72% ee . 在目前的酶促反应中,酸酐部分
Mercuric Triflate-TMU Catalyzed Hydration of Terminal Alkyne to give Methyl Ketone under Mild Conditions
Herein developed mercuric triflate-TMU catalyzed hydration of terminalalkyne is a mild procedure to give methyl ketone in excellent yield with high chemoselectivity. By using 0.05 eq of Hg(OTf)2·(TMU)2 and 3 eq of water, hydration takes place at a reasonable rate in acetonitrile.
Bromofatty aldehyde derived from bromine exposure and myeloperoxidase and eosinophil peroxidase modify GSH and protein
作者:Mark A. Duerr、Elisa N.D. Palladino、Celine L. Hartman、James A. Lambert、Jacob D. Franke、Carolyn J. Albert、Sadis Matalon、Rakesh P. Patel、Arne Slungaard、David A. Ford
DOI:10.1194/jlr.m083279
日期:2018.4
which preferentially produce hypobromousacid and α-BrFALD, accumulated FALD-GSH following PMA stimulation. Mice exposed to Br2 gas had increased levels of both α-BrFALD and FALD-GSH in the lungs, as well as elevated systemic plasma levels of FALD-GSH in comparison to mice exposed to air. Similar relative reactivity of α-ClFALD and α-BrFALD with protein thiols was shown using click analogs of these aldehydes
Reversible S-palmitoylation is an important post-translational modification that regulates the trafficking, localization, and activity of proteins. Cysteine-rich Asp-His-His-Cys (DHHC) domain-containing enzymes are evolutionarily conserved protein palmitoyl acyltransferases (PATs). The human genome encodes 23 DHHC-PATs that regulate diverse cellular functions. Although chemical probes and proteomic methods to detect palmitoylated protein substrates have been reported, no probes for direct detection of the activity of PATs are available. Here we report the synthesis and characterization of 2-bromohexadec-15-ynoic acid and 2-bromooctadec-17-ynoic acid, which are analogues of 2-bromopalmitate (2-BP), as activity-based probes for PATs as well as other palmitoylating and 2-BP-binding enzymes. These probes will serve as new chemical tools for activity-based protein profiling to explore PATs, to dissect the functions of PATs in cell signaling and diseases, and to facilitate the identification of their inhibitors.
Macrocyclization of Fischer Carbene Complexes as an Approach to Cyclophanes