die typographie des helmut schmid / the typography of helmut schmid

A Clean One-pot Synthesis of 7-Amino-5-Aryl-6-Cyano-1,5-Dihydro-2H-Pyrano[2,3-d] Pyrimidine-2,4(3H)-Diones in Aqueous Media under Ultrasonic Irradiation

“…3,4 Recently, people have paid much attention to the development of new methods for the synthesis of heterocyclic compounds, due to their potential importance in the fields of pharmaceutical and agricultural drugs. 5 Pyrimidine derivatives are generally used as antitumors, 6 analgetic substances, 7 bactericidals, 8 and fungicidal. 9 The synthesis of 7-amino-5-aryl-6cyano-1,5-dihydro-2H-pyrano [2,3-d]pyrimidine-2,4(3H)-diones by the reaction of arylidenemalononitrile with barbituric acid under traditional hot reaction condition 10,11 or microwave irradiation 5 has been reported.…”

“…One molecule of malononitrile 2 was firstly condensed with an aromatic aldehyde 1 to afford 5. Then the active methylene of barbituric acid 3 reacted with 5 via Michael addition reaction to give the intermediate 6, (6)(7). Then the intermediate 7 cyclised by nucleophilic attack of the OH group on the nitrile group and gave the intermediate 8.…”