Efficient synthesis of novel furo[2,3-d]pyrimidine derivatives under catalyst-free conditions

A series of furo2,3-d]pyrimidine derivatives were synthesized via the 3+2] cyclization of pyrimidine-4,6-diol and a variety of nitroolefins at catalyst-free conditions. The reaction is easy to perform simply mixing inexpensive starting materials in water under conventional heating at 90 °C. The reaction proceeds at a fast speed within 1.5–2 h and gives the high biological and pharmacological active substituent furo2,3-d]pyrimidine derivatives with good to high yields. Mechanism of formation of these furo2,3-d]pyrimidine derivatives are also proposed.