An Efficient One-pot Two-component Protocol for Regio- and Chemoselective Synthesis of 5-Aryloyl-1,3,7,9-tetraalkyl-2,8-dithioxo-2,3,8,9-tetrahydro-1H-pyrano[2,3-d:6,5-d′]dipyrimidine-4,6(5H,7H)-diones

Abstract

Novel symmetric fused pyrano [2,3-d]pyrimidine derivatives were synthesized in 75-92 % yield by a one-pot twocomponent reaction of arylglyoxals and 1,3-dialkyl-2-thiobarbituric acids in ethanol at room temperature. This is the first protocol to be reported for the synthesis of 5-aryloyl-1,3,7,9-tetraalkyl-2,8-dithioxo-2,3,8,9-tetrahydro-1H-pyrano [2,3-d:6,5-d 0 ]dipyrimidine-4,6(5H,7H)-diones and the significant features of the present protocol are simplicity, high yields, a simple isolation procedure, and high chemoselectivity.

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

“…These precipitates were isolated and recrystallized in methanol. Our aim from adding ammonium acetate to the reaction mixture was the synthesis of pyrrolopyrimidine derivatives but considering 1 H-nmr spectra of all products showed that similar to our previously synthesized dialkyl substituted pyrano [2,3-d]pyrimidines, 20 there is a singlet in the average chemical shift 5.5 ppm which relates to CH of pyran ring. Namely, ammonium acetate instead of addition on carbonyl groups of 1,4-dicarbonyl intermediate acts as catalyst in these reactions and it helps to close pyran system on the pyrimidinone rings.…”

“…Following to our recent work on the synthesis of new substituted pyranopyrimidines, 20 we found that unlike 1,3-diethyl and 1,3-dimethylthiobarbituric acids, stirring the mixture of barbituric acid or thiobarbituric acid and arylglyoxalmonohydrates in ethanol in both room temperature and reflux conditions in order to synthesis of the corresponding 5-aryloyl substituted pyrano [2,3-d]pyrimidines was failed which this phenomenon may be because of poor solublity of barbituric acid and thiobarbituric acid in ethanol. Therefore, we changed the reaction solvent to water as a suitable solvent for barbituric acid derivatives.…”

ZrOCl2.8H2O as a green and efficient catalyst for the expeditious synthesis of substituted 3-arylpyrimido[4,5-c]pyridazines in water

“…Exposure to pyridine has harmful effects on the liver, kidneys, immune systems and reproductive functions, and has potential carcinogenicity. [27][28][29][30][31] Following to recent reports about the application of arylglyoxals (AG) in heterocyclic chemistry, 26,[32][33][34][35][36][37][38][39][40] herein we have applied ZrOCl2•8H2O as recyclable, non-toxic and green catalyst for the regioselective synthesis of 3-arylpyrimido [4,5-c] We also studied the influence of the amount of ZrOCl2•8H2O on the reaction yields. We found that the best yield is obtained when we used the ZrOCl2•8H2O 20 mol% as a catalyst.…”

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

“…Rimaz et al 192 developed the chemo- and regioselective synthesis of a novel symmetric fused 158a through the reaction of arylglyoxal 157 (1 mmol) with 11a / 11b (1 mmol) in absolute alcohol (10 mL) at room temperature for appropriate hours ( Scheme 106 ). The enol form 158a was stable only in solution phase and all the compounds were gained in keto form 158 .…”