| Research Abstract |
This project has been directed toward the development of synthetic accesses to functionalized heterocyclic compounds. The results obtained are demonstrated as belows; 1.A 5,6-dihydro-5,6-bis(methylene)-2,4(1H,3H)-pyrimidinedione intermediate was generated by the treatment of 5-formyl-1,3,6-trimethyl-2,4 (1H,3H)-pyrimidinedione with magnesium salt and DBU. The enolate underwent[4 + 2]cycloaddition reaction with olefins in highly regio-and stereoselective manners. By similar methods,enolates in 4(1H)-pyridone and DELTA^3-phrazolin-5-one systems were obtained and the cycloaddition reactions using these enolates leading to quinolines and indazoles were investigated. 2.The reaction of 6-alkenylamino-5-formyl-1,3,6-trimethyl-2,4(1H,3H)-pyrimidinedione with alpha-amino acid derivatives afforded intramolecular azomethine ylide adducts and ene reaction products. The reaction paths depended on the nature of the amino acids;the reaction with N-substituted amino acid derivatives gave azomethine ylide intermediates. On the other hand,the reaction with N-unsabstituted ones gave the imines as intermediates,which underwent imine-ene reaction to form fused azepines. Similar bident reaction profiles were elucidated in the reactions of 2(1H)-pyridone,chromenone,and pyridopyrimidine systems. 3.Functionalized carbodiimides were used as a synthetic building block for heterocyclic systems such as pyridine,pyrimidine,and imidazole.
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