A convenient synthesis of pyridine and 2,2′-bipyridine derivatives
摘要:
alpha-Chloro-alpha-acetoxy-beta-keto-esters 9 were readily prepared from beta-keto-esters 6 in good overall yields. These compounds reacted as alpha,beta-diketo-ester equivalents 2 with amidrazones 1 yielding triazines 3, generally in good yields. Picolinates 10 provided an alternative source of alpha,beta-diketo-ester equivalents 2 when treated with copper(II) acetate. A 'one-pot' reaction of the alpha,beta-diketo-ester equivalents 2 with amidrazones 1 in the presence of 2,5-norbornadiene 5 in boiling ethanol yielded the pyridines 4 and 2,2'-bipyridines 4 (R-1=2-pyridyl) directly without the need to isolate the corresponding triazines 3. Triazine 3c reacted with the aza-dienophiles 13 and 17 affording the products 16 and 18, respectively, in good yields. (C) 2008 Elsevier Ltd. All rights reserved.
Electrochemically Induced Intermolecular Cross-Dehydrogenative C–O Coupling of β-Diketones and β-Ketoesters with Carboxylic Acids
作者:Oleg V. Bityukov、Olesya K. Matveeva、Vera A. Vil’、Vladimir A. Kokorekin、Gennady I. Nikishin、Alexander O. Terent’ev
DOI:10.1021/acs.joc.8b02791
日期:2019.2.1
The electrochemicallyinduced cross-dehydrogenative C–O coupling of β-diketones and β-ketoesters (C–H reagents) with carboxylic acids (O–H reagents) was developed. An important feature of this reaction lies in the selective formation of intermolecular C–O coupling products in high yields, up to 92%, using DMSO as a solvent with a broad substrate scope in an undivided cell equipped with carbon and platinum