Enaminones in heterocyclic synthesis: A new regioselective synthesis of 2,3,6‐trisubstituted pyridines, 6‐substituted‐3‐aroylpyridines and 1,3,5‐triaroylbenzenes
作者:Balkis Al‐Saleh、Mervat Mohammed Abdelkhalik、Afaf Mohammed Eltoukhy、Mohammed Hilmy Elnagdi
DOI:10.1002/jhet.5570390528
日期:2002.9
1-Substituted-3-dimethylaminopropenones 1a-d reacted with acetylacetone and with ethyl acetoacetate to yield regioselectively 2,3,6-trisubstituted pyridines. Refluxing 1a-d in acetic acid/ammonium acetate resulted in the formation of 6-substituted-3-aroylpyridines, whereas refluxing in acetic acid alone afforded 1,3,5-triaroylbenzene.
Robust and General Late-Stage Methylation of Aryl Chlorides: Application to Isotopic Labeling of Drug-like Scaffolds
作者:Elliot Davenport、Daniela E. Negru、Geoff Badman、David M. Lindsay、William J. Kerr
DOI:10.1021/acscatal.3c02761
日期:2023.9.1
highly efficient, robust palladium-catalyzedapproach, optimized via high-throughput experimentation, for the methylation of aryl chlorides using potassium methyltrifluoroborate. A practically straightforward route to isotopically labeled methylating agents has also been developed, and the methodology applied to isotopologue synthesis, including the installation of isotopic labels in a range of drug-like
A concise copper-catalyzed N-O bond cleavage/C-C/C-N bond formation procedure has been described for the synthesis of multisubstituted pyridines. Various oxime acetates, activated methylene compounds, and a wide range of aldehydes bearing aryl, heteroaryl, vinyl, and trifluoromethyl groups were employed to provide the tri- or tetrasubstituted pyridines with flexible substitution patterns. Moreover, this method features inexpensive catalysts, no need for extra oxidant, and high step-enconomy, which make it pratical and attractive.
A highly efficient regioselective one-pot synthesis of 2,3,6-trisubstituted pyridines and 2,7,7-trisubstituted tetrahydroquinolin-5-ones using K5CoW12O40·3H2O as a heterogeneous recyclable catalyst
A systematic investigation into the regioselective one-pot, three-component condensation of enaminones la-g, beta-dicarbonyl compounds 2a-c, and ammonium acetate in the presence of a catalytic amount of K5CoW12O40 center dot 3H(2)O (0.01 equiv or 1.0 mol %) under solvent free conditions, as well as in refluxing isopropanol, has been reported. The reaction was highly efficient to produce 2,3,6-trisubstituted pyridines 3a-g, 4a-g, and novel 2,7,7-trisubstituted-5,6,7,8-tetrahydroquinoline-5-ones 5a-g in excellent yields. The present procedure offers advantages of short reaction time, simple work-up, and the catalyst exhibited remarkable reusable activity. (c) 2007 Elsevier Ltd. All rights reserved.