N-(tert-Butoxycarbonyl)-N-[(triethylenediammonium)sulfonyl]azanide: A Convenient Sulfamoylation Reagent for Alcohols
摘要:
A convenient and efficient procedure is described for the sulfamoylation of alcohols using N-(tertbutoxycarbonyl)-N-[(triethylenediammonium)sulfonyl]azanide (1). The ambient temperature stable reagent 1 reacts with phenols as well as primary and secondary alcohols to give high to modest yields. The relative reaction rate of substrates was determined (primary > phenol > secondary tertiary). The reagent's utility as a selective sulfamoylation reagent with polyols is also demonstrated.
The invention relates to an image support medium for creation of an aesthetic image that is an work or object for display. This support medium includes a polymer in an amount sufficient to enable the image to have at least one aesthetic element. In different embodiments, the image support medium is an image support stabilizer, the polymer is a synthetic absorbent or conductive polymer, or the polymer is a transparent or synthetic translucent polymer and a property of this transparent or translucent polymer is enhanced to facilitate the creation or preservation of the image by at least one stabilizer. The invention also relates to a method for preparing this image support medium. The method includes forming a reaction mixture comprising a monomer in an amount sufficient to provide or enable the image to have an aesthetic element, and processing the reaction mixture into a 2- or 3-dimensional shape.
Carbohydrate−Carbohydrate Interactions in Water with Glycophanes as Model Systems
作者:Juan Carlos Morales、Dácil Zurita、Soledad Penadés
DOI:10.1021/jo9807823
日期:1998.12.1
The synthesis and conformational properties of glycophanes 2 and 3 (cyclodextrin-cyclophane hybrid receptors containing two maltose units linked by (4-hydroxymethyl) benzoic acid spacer) are described. The binding properties in water of these receptors with a series of 4-nitrophenyl glycosides with alpha- and beta-configurations at the anomeric center have been studied using H-1 NMR spectroscopy and molecular mechanics calculations. A comparison of these properties with those of glycophane 1 (an alpha,alpha-trehalose containing glycophane) and alpha-cyclodextrin (alpha CD) using the same glycosides shows the existence of a stabilizing contribution to the free energy of binding in the case of of glycophanes but not in the case of the alpha CD system. This contribution is due to carbohydrate - carbohydrate interactions between both host and guest lipophilic sugar surfaces. Glycophanes 1, 2, and 3 show similar alpha/beta selectivity on binding the ligands, despite the great flexibility of 3 related to 1 and 2. Parallels are drawn between the thermodynamic behavior of these model systems and that proposed for sugar-protein interactions.
CROSSLINKED POLED POLYMERS FOR NONLINEAR OPTIC APPLICATIONS AND METHOD OF MAKING THEM
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0583417A1
公开(公告)日:1994-02-23
METHOD AND COMPOSITION FOR DETECTING BACTERIAL CONTAMINATION IN FOOD PRODUCTS