Efficient access to novel 5-aryloyl-1H-pyrano[2,3-d:6,5-d']dipyrimidine-2,4,6,8(3H,5H,7H,9H)-tetraones and their sulfur analogs in water

Abstract

An efficient chemoselective synthesis of novel substituted pyrano [2,3-d]pyrimidines is described. A number of pyrano[2,3-d:6,5-d']dipyrimidine-2,4,6,8(3H,5H,7H,9H)-tetraones and their sulfur analogs were synthesized through a one-pot condensation of arylglyoxal monohydrates with barbituric acid and thiobarbituric acid in the presence of excess ammonium acetate in water at room temperature, affording the desired products in moderate to good yields.

Aryl glyoxal: a prime synthetic equivalent for multicomponent reactions in the designing of oxygen heterocycles

“…They obtained the desired products through an excess ammonium acetate-catalyzed one-pot condensation of aryl glyoxal monohydrate 1 with barbituric acid 19 using the greenest solvent water at room temperature (Scheme 39). 69 Rimaz and co-workers reported the synthesis of pyranofused pyrimidines derivatives 75 by the regioselective pseudothree-component condensation reaction of aryl glyoxal monohydrate 1 and 1-ethyl-2-thioxodihydropyrimidine-4,6(1H,5H)dione 19 under a catalytic system employing DABCO or ZrOCl 2 $8H 2 O in ethanol at 50 °C. The pyrano-fused-pyrimidine scaffold in the synthesized compound was identied as possessing HIV integrase inhibitor activity (Scheme 40).…”

“…They obtained the desired products through an excess ammonium acetate-catalyzed one-pot condensation of aryl glyoxal monohydrate 1 with barbituric acid 19 using the greenest solvent water at room temperature (Scheme 39). 69…”

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

“…Rimaz et al 138 reported a highly regio-chemoselective synthesis of pyrano[2,3-d:6,5- d ′]dipyrimidine-2,4,6,8-(3 H ,5 H ,7 H ,9 H )-tetraones 102 and its sulfur analogue by reacting 100 (1 mmol) with 12 (2 mmol) in excess ammonium acetate (5 mmol) and water at RT ( Scheme 72 ). Only in 4-Cl and 4-F analogues of 102 undergo keto–enol tautomerism in DMSO- d 6 solution, but the leading tautomer was keto only.…”

Recent advancements in the multicomponent synthesis of heterocycles integrated with a pyrano[2,3-d]pyrimidine core

“…Rimaz et al 120 reported multicomponent one-pot reactions of aryl glyoxal monohydrates 46 (1 equiv.) with (thio)barbituric acids 47 (2 equiv.)…”

“…The mechanism of this reaction was projected by the formation of N,N-dimethyl-formamidine intermediate from the reaction of 4H-pyran 43 with DMF-DMA, pyrimidine ring cyclization by reaction with hydrazine hydrate, condensation of the amino group of 44 with aryl aldehydes, and imino group with dichloro(phenyl)-phosphine, hydrolysis, tautomerization, and triazaphosphinine ring cyclization through the Pudovik reaction. 119 Rimaz et al 120 reported multicomponent one-pot reactions of aryl glyoxal monohydrates 46 (1 equiv.) with (thio)barbituric acids 47 (2 equiv.)…”