2004

Fused pyrimidine derivativesR 0515 A Facile Microwave-Induced One-Pot Synthesis of Novel Pyrimido[4,5-d]pyrimi-

dines and Pyrido[2,3-d]pyrimidines under Solvent-Free Conditions. — Pyrimi-dine compound (I) undergoes [4 + 2] cycloaddition reactions with benzaldimines (II), quinones (IV), or coumarins (VI) to give the title products in excellent yields under sol-vent-free conditions and microwave irradiation. Compared to conventional heating in a solvent, the reaction times are significantly shortened from hours to minutes, and the yields are about 20% higher. — (GOHAIN, M.; PRAJAPATI*, D.; GOGOI, B. J.; SANDHU, J. S.; Synlett 2004, 7, 1179-1182; Div. Med. Chem., Reg. Res. Lab., Jorhat 785 006, India; Eng.) — Klein

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