Ring closure reactions of pyrido[2,3-d]pyrimidines to Pyrano[2′,3′:4,5]- and Oxazolo[5′,4′:4,5]pyrido[2,3-d]pyrimidines

被引:2
|
作者
Van Tinh, Dang [2 ]
Stadlbauer, Wolfgang [1 ]
机构
[1] Karl Franzens Univ Graz, Inst Chem, Organ Synth Grp, A-8010 Graz, Austria
[2] Univ Med & Pharm Hochiminh City, Ho Chi Minh City, Vietnam
关键词
D O I
10.1002/jhet.5570450517
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The cyclocondensation of 5-hydroxy-pyrido[2,3-d]pyrimidines 1 with malonates gives pyrano[2 ',3 ':4,5]pyrido-[2,3-d]pyrimidines 2. Nitration of 1 and reduction with zinc in the presence of carboxylic acids/anhydrides gave 2-alkyloxazolo[5 ',4 ':4,5] pyrido[2,3-d] pyrimidines 4, which were ring-opened to 6-aminopyrido[2,3-d]pyrimidines 5, 6 and 7. Cyclization of 6-aminopyrido[2,3-d]pyrimidines 6 with benzoylchlorides 8 gave 2 -aryloxazolo[5 ',4 ':4,5]pyrido[2,3 -djpyrimidines 9. Reaction conditions for the cyclization have been studied by differential scanning calorimetry (DSC).
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页码:1359 / 1364
页数:6
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