General Method for the Preparation of Substituted 2-Amino-4H,5H-pyrano[4,3-b]pyran-5-ones and 2-Amino-4H-pyrano[3,2-c]pyridine-5-ones

Abstract

Abstract:Reaction of 4-hydroxy-6-methyl-2-pyrone (1a) as well as 4-hydroxy-6-methyl-2(1H)-pyridones (1b-d) with arylmethylene malononitriles or arylmethylene methyl cyanoacetates (2a-h) leads to the formation of the very stable 5,6-fused bicyclic 2-amino-4H-pyran derivatives 3a-3af.

Organocatalysis in Synthesis: L-Proline as an Enantioselective Catalyst in the Synthesis of Pyrans and Thiopyrans

“…The addition of active methylene reagents to arylidenemalononitrile in the presence of homogeneous basic catalysts has been extensively used in the past for the synthesis of these compounds [7,8,9,10,11,12]. Interest in these reactions has recently been revived [13,14] with the aim of developing green laboratory reaction conditions [15,16], such as replacing homogeneous catalysis with heterogeneous ones [17,18,19,20], to synthesize enantiomerically pure pyrans for which diverse biological applications were noticed [21,22,23] and patented [24,25,26].…”

Ionic Liquid Promoted Efficient and Rapid One-pot Synthesis of Pyran Annulated Heterocyclic Systems

“…ethanol, methanol and pyridine. However, most of these rely on multi-step reactions and complex synthetic pathways, long reaction times and yields are low [2][3][4][5][6][7][8][9][10][11][12][13].…”

Ball Mill–assisted Preparation of Nano-CaCO3 as a Novel and Green Catalyst–based Eggshell Waste

“…Pure pyrano [4,3-b]pyrans were obtained in high yields without any more purification. All compounds were known in the literature 13,[19][20][21] and the NMR and IR spectra of the products were in agreement with earlier data. 13,[19][20][21] Spectra data of 2-amino-7-methyl-5-oxo-4-(4-chlorophenyl)-4H,5H-pyrano [4,3-b]pyran-3-carbonitrile ( …”