Esterification of sterically hindered acids and alcohols in fluorous media
作者:Badra Gacem、Gérard Jenner
DOI:10.1016/s0040-4039(02)02872-1
日期:2003.2
Sterically hindered esterification reactions are best performed in specific fluorous media in the presence of catalytic amounts of diphenylammonium triflate. Fluorous media, in addition to their positive effect on yields, have inherent favorable properties respecting environment and permitting simple work-up. Highly congested reagents, however, react only marginally.
Efficient Combination of Recyclable Task Specific Ionic Liquid and Microwave Dielectric Heating for the Synthesis of Lipophilic Esters
作者:Atef Arfan、Jean Pierre Bazureau
DOI:10.1021/op058002x
日期:2005.11.1
Mild and efficient esterification reactions of carboxylic acids with neo-pentanol were carried out using task-specificionicliquids with hydrogen sulphate counteranion under microwave irradiation. The latent acidity of the ionicliquid was introduced by anion metathesis from hydrogen sulphate with the corresponding imidazolium or pyridinium halides. The catalyst [C4mim][HSO4] modified with 5% of concentrated
Nickel-Catalyzed Selective Conversion of Two Different Aldehydes to Cross-Coupled Esters
作者:Yoichi Hoshimoto、Masato Ohashi、Sensuke Ogoshi
DOI:10.1021/ja109908x
日期:2011.4.6
In the presence of a Ni(0)/NHC catalyst, an equimolar mixture of aliphatic and aryl aldehydes can be employed to selectively yield a single cross-coupled ester. This reaction can be applied to a variety of aliphatic (1 degrees, 2 degrees, cyc-2 degrees, and 3 degrees) and aryl aldehyde combinations. The reaction represents 100% atom efficiency and generates no waste. Mechanistic studies have revealed that the striking feature of the reaction is the simultaneous coordination of two aldehydes to Ni(0).
CARBACEPHEM BETA-LACTAM ANTIBIOTICS
申请人:Wagman Allan S.
公开号:US20100267686A1
公开(公告)日:2010-10-21
Carbacephem β-lactam antibiotics having the following chemical structures (I) and (II) are disclosed:
including stereoisomers, pharmaceutically acceptable salts, esters and prodrugs thereof, wherein Ar
2
, R
1
, R
2
and R
3
are as defined herein. The compounds are useful for the treatment of bacterial infections, in particular those caused by methicillin-resistant
Staphylococcus
spp.