Synthesis of some novel annulated pyrido[2,3-d]pyrimidines via stereoselective intramolecular hetero Diels–Alder reactions of 1-oxa-1,3-butadienes

• Mohit L. Deb and
• Pulak J. Bhuyan

Beilstein J. Org. Chem. 2010, 6, No. 11, doi:10.3762/bjoc.6.11

• Mohit L. Deb Pulak J. Bhuyan Medicinal Chemistry Division, North East Institute of Science & Technology, Jorhat 785006, Assam, India, Fax: 0376 2370011 10.3762/bjoc.6.11 Abstract Some novel annulated pyrido[2,3-d]pyrimidines 6 and 7 were synthesized stereoselectively by intramolecular hetero

• Diels–Alder reactions involving 1-oxa-1,3-butadienes. Keywords: β-halo aldehydes; hetero Diels–Alder reaction; 1-oxa-1,3-butadiene; pyrido[2,3-d]pyrimidines; uracil; Introduction The importance of uracil and its annulated derivatives is well recognized by synthetic as well as biological chemists [1][2

• ][3][4][5][6][7][8]. Pyrido[2,3-d]pyrimidines represent a broad class of annelated uracils which have received considerable attention over the past years due to their wide range of biological activities such as antibacterial [9][10], antitumor [11][12], cardiotonic [13][14], hepatoprotective [13

One-pot synthesis of novel 1H-pyrimido[4,5-c][1,2]diazepines and pyrazolo[3,4-d]pyrimidines

• Dipak Prajapati,
• Partha P. Baruah,
• Baikuntha J. Gogoi and
• Jagir S. Sandhu

Beilstein J. Org. Chem. 2006, 2, No. 5, doi:10.1186/1860-5397-2-5

• synthesised by Mallory et al is susceptible to ring-opening/ring-closure rearrangement reactions. Depending on the nature of the substituents, their location, and reaction conditions, the pyrimidodiazepines were converted into either pyrido [2,3-d]pyrimidines, pyrazolo [3,4-d]pyrimidines or a pyrimido [4,5-c