An eco-friendly, simple, mild, chemo selective and highly efficient procedure for the acylation of primary and secondary amine function in various structurally and electronically aliphatic and aromatic compounds affording their corresponding N-Ac derivatives is developed. Mild conditions, simplicity and easier work-up are the main advantages of this method.
CATIONIC CONTRAST AGENTS AND METHODS OF USING THE SAME
申请人:The Trustees of the University of Pennsylvania
公开号:US20160287726A1
公开(公告)日:2016-10-06
Gadolinium complexes for use as contrast agents, and methods for making and using the gadolinium complexes, are described. The contrast agent complexes preferably have a net positive charge, and can electrostatically interact with glycosaminoglycans to improve the delineation of fine tears within cartilage, detection of cartilage degeneration, or assessment of cartilage thickness, morphology, or glycosaminoglycan content via magnetic resonance imaging.
N-(Alkylsulfamoyl)aldimines: easily deprotected precursors for diarylmethylamine synthesis
作者:Rosemary H. Crampton、Martin Fox、Simon Woodward
DOI:10.1016/j.tetasy.2013.04.006
日期:2013.5
The sequential reaction of chlorosulfonyl isocyanate with t-BuOH, t-BuNH2 and TFA allows formation of H2NSO2NHBut. Condensation of the latter with Ar1CHO in the presence of Ti(OEt)4 provides the activated imines Ar1CHNSO2NHBut (59–89%). Commercially available boronic acids add to these imines with good stereoselectivity (76–98% ee) using readily available diene ligands. Simple deprotection with 5%
Simple, rapid, and clean condensation of sulfonamide and maleic anhydride derivatives: Synthesis of novel 1<i>H</i>- Pyrrole-2,5-diones under heterogeneous conditions
GRAPHICAL ABSTRACT ABSTRACT H6P2W18O62 is used as an efficient catalyst for the synthesis of novel N-substituted sulfonyl maleimides (1H-Pyrrole-2,5-diones) via the condensation of sulfonamide and maleic anhydride derivatives. The Dawson heteropolyacid was used with a catalytic amount of 2 mmol% in acetonitrile at reflux. The reuse of H6P2W18O62 as heterogeneous catalyst several times without decrease
Efficient<i>N</i>-acylation of sulfonamides using cesium salt of Wells–Dawson heteropolyacid as catalyst: Synthesis of new<i>N</i>-acyl sulfonamides and cyclic imides
Abstract N-acylation of substituted sulfonamides with different anhydrides in the presence of Cesium salt of Wells–Dawson heteropolyacid (Cs5HP2W18O62) as an efficient and reusable catalyst was investigated for the first time. Cs5HP2W18O62 was used with a catalytic amount in water as a green solvent. At room temperature, a series of N-acylsulfonamides were synthesized, while under refluxing conditions