Cyclic Ether Synthesis via Palladium-Catalyzed Directed Dehydrogenative Annulation at Unactivated Terminal Positions
作者:Samuel J. Thompson、Danny Q. Thach、Guangbin Dong
DOI:10.1021/jacs.5b07384
日期:2015.9.16
Here, a palladium-catalyzed functionalization of unactivated sp(3) C-H bonds with internal alcohol nucleophiles is described. Directed by an oxime-masked alcohol, annulation chemoselectively occurs at the β position, leading to a range of aliphatic cyclic ethers with four- to seven-membered rings. Tethered primary, secondary, and tertiary free hydroxyl groups can all react to give the corresponding
The present invention provides methods and compositions for assaying biological samples, such as human serum, for barbiturates. In one aspect, analogs of barbiturates derivatized with fluorescein and analogs of barbiturates derivatized with immunogenic polypeptides are provided. The fluorescent analogs are employed as tracers in a competitive homogeneous immunoassay, i.e., a fluorescence polarization immunoassay, for detecting barbiturates. The immunogenic analogs are employed to make anti-barbiturate antiserum of the invention for use in the immunoassay method. Intermediates for preparing the fluorescent and immunogenic analogs are also provided. Further provided are test kits, comprising a fluorescent tracer and an antiserum according to the invention, for analyzing biological samples by fluorescence polarization immunoassay for the presence of a barbiturate. Further, an improvement is provided in immunoassays for analytes in serum, wherein a transfer means, such as a pipette, is used repeatedly to transfer different samples into the assay system. In the improvement, an aqueous solution of specified composition, comprising dimethylsulfoxide and an alkali halide, is used to wash the transfer means between transfers.
Hexanes/acetonitrile: a binary solvent system for the efficient monosilylation of symmetric primary and secondary diols
作者:Burkhardt I. Wilke、Mark H. Dornan、Jon Yeung、Christopher N. Boddy、Atahualpa Pinto
DOI:10.1016/j.tetlet.2014.02.067
日期:2014.4
Symmetric diols are useful compounds in the synthesis of natural products, their value often dependent on their successful monoprotection. A general and simple method for the monosilylation of symmetrical primary and secondary diols is reported. The method exploits the solubility differential of diols and their monosilylated counterparts in a binary hexanes/acetonitrile solvent system. (C) 2014 Elsevier Ltd. All rights reserved.