Highly chemo- and regioselective rearrangement of α,β-epoxy ketones to 1,3-dicarbonyl compounds in 5 mol dm−3 lithium perchlorate–diethyl ether medium
作者:S. Sankararaman、J. E. Nesakumar
DOI:10.1039/a905619j
日期:——
Epoxides from α,β-unsaturated ketones undergo highly chemo- and regioselective rearrangement to 1,3-dicarbonyl compounds in 5 mol dm–3 lithium perchlorate–diethyl ether medium by a 1,2-migration of the carbonyl group at ambient conditions.
Various cyclic α,β-epoxy ketones rearranged to α-formyl ketones and/or vic-diones in the presence of catalytic amounts of zeolites and montmorillonite K10. This provides an excellent alternative to conventional homogeneous systems with respect to yields and workup. Differences in product distribution and type of products in the rearrangement of pulegone oxide could be reasonably explained by invoking
Novel pyrazolopyrimidines as cyclin dependent kinase inhibitors
申请人:Guzi J. Timothy
公开号:US20080050384A1
公开(公告)日:2008-02-28
In its many embodiments, the present invention provides a novel class of pyrazolo[1,5-a]pyrimidine compounds as inhibitors of cyclin dependent kinases, methods of preparing such compounds, pharmaceutical compositions containing one or more such compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention, inhibition, or amelioration of one or more diseases associated with the CDKs using such compounds or pharmaceutical compositions.
Bicyclic delta-lactones with a carbon group at the bicyclic junction C-7a, designed as pseudoiridolactones, were synthesized from alpha-alkyl-alpha-hydroxymethylcyclopentanones via an intramolecular Horner-Wadsworth-Emmons reaction. (c) 2007 Elsevier Ltd. All rights reserved.
The Intramolecular Aldol Condensation Route to Fused Bi- and Tricyclic β-Lactams<sup>1</sup><sup>,</sup><sup>2</sup>
作者:Benito Alcaide、Concepción Polanco、Elena Sáez、Miguel A. Sierra
DOI:10.1021/jo960904w
日期:1996.1.1
Staudinger cycloaddition of activated acid chlorides to 1,3-ketoaldimines, prepared in quantitative yields from 1,3-ketoaldehydes and amino esters, gave in excellent yields cis-a-azetidinones, 6-8, having the adequate functionality to obtain fused bi- and tricyclic beta-lactams. Reaction of compounds 6 with LHMDS at low temperature gave a single diastereomer of fused bicyclic compounds with a carbapenam or carbacefam skeleton. Treatment of diastereomeric cis-2-azetidinones, 7/8, in analogous conditions resulted either in the exclusive cyclization of one of the two diastereomers to form tricyclic [4.n.m] (n = 5, 6; m = 5, 6) compounds, or in the cyclization of both diastereomers to form tricyclic [4.n.7] (n = 5, 6) 2-azetidinones. In all cases the cyclization step was totally stereoselective. Alternatively, trans-carbapenams and one example of a tricyclic system having a trans-2-azetidinone ring have been obtained by using longer reaction times and higher temperatures. Epimerization at C3 of the 2-azetidinone nucleus occurs in these reaction conditions to obtain a single diastereomer of the final products. This approach to fused policyclic 2-azetidinones is one of the scarce syntheses of this kind of compound making use of the aldol condensation.