| 摘要 |
Title conpds. (Ia, Ib; R1, R2 = lower alkyl; R3 = H, halogen, lower alkyl, lower alkoxy) were prepd. by Diels-Alder cyclization of compd. II and III. Thus, 61.5 g 1,3-dimethyl-2-pyridone and 86.5 g N-phenylmaleimide in 500 ml xylene were refluxed for 24 hr and crustallized at room temp. for 1 day to give 2,4-dimethyl-3-oxo-2-azabicyclo(2,2,2)octa-7-en-5,6-oxo-dicarboxylic acidN-phenylimid (m.p. 219 ≦̸C).
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