A solid phase approach to substituted pyrimidines and their conversion into condensed heterocycles for potential use in combinatorial chemistry.
A novel general synthesis of substituted pyrimidine 3 has been carried out on solid support. The C-atoms carring the cyano, amino, carboxamido, as well as anchoring site have exploited to generate libraries of compounds 6-8, 10, 13, 15, 17, 19, 21, 23, 25 and 27. A novel strategy to cleave the resin to resin-site unsubstituted system has been developed and it provides 5,6-disubstituted pyrimidines 6-8. In addition, synthesis of 2,5,6-trisubstituted pyrimidines of prototype 10 were carried out by nucleophilic displacement of the anchor by various amines. Further investigations were directed toward the solid phase synthesis of pyrimido[4,5-d]pyrimidines 12, 16, 20 and 24 in which C-atoms carring the oxo, thio, amino, anchoring site as well as NH could be introduced as center of diversity to generate libraries of compounds for potential use. 4-Aminopyrimido[4,5-d]pyrimidines 13 and 17 were obtained from fusion of 3a with urea or thiourea followed by cleavage of support while 3-phenylpyrimido[4,5-d]pyrimidines 21 and 27 were synthesized from cyclisation of 4 with phenyl isocyanate or isothiocyanate followed by release of resin. 7-substituted pyrimido[4,5-d]pyrimidines 15, 19, 23 and 27 were obtained by oxidation of 12, 16, 20 and 24 followed by aminolytic cleavage of support.
Division of Medicinal Chemistry, Central Drug Research Institute, Lucknow, India.
S K
SK
Srivastava
W
W
Haq
P M
PM
Chauhan
D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D011743:Pyrimidines / Q000737:chemistry*
D006571:Heterocyclic Compounds; D007202:Indicators and Reagents; D011743:Pyrimidines