An Improved Synthesis of Cyclic Hydroxamic Acids from Gramineae
摘要:
The boron trichloride sensitive methoxymethyl (MOM) protecting group has been used to efficiently synthesize polymethoxylated derivatives of the benzoxazinone family of cyclic hydroxamic acids. The MOM group allows the unveiling of the hemiacetal at C-2 of these compounds without demethylating ring methoxy substituents, resulting in greatly increased yields.
Advances in the field of phosphorus chemistry are documented, by revealing the synthetic utility of previously underutilized quaternary phosphiranium salts (QPrS) as three‐chain‐atom electrophilic building blocks. Notably, control of their challenging C‐centered electrophilicity is disclosed with an expedient synthesis of tertiary β‐anilino phosphines as a proof‐of‐concept.
We report the preparation of phosphiranium salts by quaternarization of phosphiranes, a class of sensitive, highlystrained, and poorly nucleophilic cyclic phosphines. High-yielding introduction of a varied set of alkyl groups including methylene ester arms was accomplished under mild conditions. A Cu-catalyzed electrophilic arylation of phosphiranes using diaryl iodonium reagents was also achieved
我们报告了通过 phosphiranes 季铵化制备 phosphiranium 盐,这是一类敏感的、高度紧张的、亲核性差的环膦。在温和条件下实现了包括亚甲基酯臂在内的一系列不同烷基的高产率引入。还实现了使用二芳基碘鎓试剂对磷烷进行 Cu 催化的亲电芳基化,以产生前所未有的 P,P-二芳基磷鎓盐,并具有良好的效率。
Ruthenium complexes of tetradentate bipyridine ligands: highly efficient catalysts for the hydrogenation of carboxylic esters and lactones
作者:Wei Li、Jian-Hua Xie、Ming-Lei Yuan、Qi-Lin Zhou
DOI:10.1039/c4gc00835a
日期:——
A new type of readily available, air-stable ruthenium complex of tetradentate bipyridine ligands has been developed. These complexes displayed exceptional efficiency for the hydrogenation of aromatic and aliphatic carboxylicesters and lactones at as low as 10 ppm catalyst loading under very mild conditions.
Esters of unsymmetrically 2-substituted glycolic acid dimers
申请人:E. I. Du Pont de Nemours & Company
公开号:US05254718A1
公开(公告)日:1993-10-19
This invention concerns esters of unsymmetrically 2-substituted glycolic acid dimers, a process for their preparation and their use in the preparation of unsymmetrically 3,6-substituted 1,4-dioxane-2,5-diones.
Provided herein are compounds, compositions and methods for the treatment of Flaviviridae infections, including HCV infections. In certain embodiments, compounds and compositions of nucleoside derivatives are disclosed, which can be administered either alone or in combination with other anti-viral agents.