Enaminones as Building Blocks In Heterocyclic Synthesis: A New One Pot Synthesis of Polyfunctional Substituted Pyridines
作者:Samia Michel Agamy、Mervat Mohammed Abdel-Khalik、Mona Hassan Mohamed、Mohammed Hilmy Elnagdi
DOI:10.1515/znb-2001-1016
日期:2001.10.1
Enaminones react with a variety of active methyl and methylene reagents in presence of ammonium acetate to yield functionally substituted pyridines in good yields. The reaction proceeded via initial Michael addition across the double bond followed by cyclization. The reaction of enaminone with aromatic aldehyde in acetic acid/ammonium acetate afforded the dihydropyridine that was oxidized to the corresponding
A convenient synthesis of pyridine and 2,2′-bipyridine derivatives
作者:Marta Altuna-Urquijo、Alexander Gehre、Stephen P. Stanforth、Brian Tarbit
DOI:10.1016/j.tet.2008.11.090
日期:2009.1
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.