新型2-氧代-1,2,4-三唑并[3,2-d][1,5]苯并氧氮杂类稠杂环的合成

Synthesis of Novel 2-Oxo-1,2,4-[triazolo][3,2-d] [1,5]benzoxazepine Derivatives

将取代色满酮 ( 1 )与芳肼反应生成的腙与 HNCO发生 [3 +2 ]环加成反应 ,加成产物 ( 2 )经氧化得到偕偶氮异氰酸酯 ( 3 ) .化合物 3在 HBF4 的催化下发生环化 -重排反应 ,得到新颖的三环系 2 -氧代 -1 ,2 ,4-三唑并[3 ,2 -d][1 ,5 ]苯并氧氮杂化合物 5 a～ 5

Many [1,2,4]triazolobenzoheteroazepine derivatives show interesting biological activities. In this paper, the geminal arylazo isocyanato compounds 3 were prepared from chroman-4-ones in three steps, i.e. condensation with arylhydrazine, cycloaddition of the resulting hydrazone with HNCO, and oxidative ring cleavage by KMnO 4. Compounds 3 were allowed to react with HBF 4, producing the respective 3-spiro substituted 1-aryl-4,5-dihydro-5-oxo-3H-1,2,4-triazolium salts 4. The concurrent rearrangement of compound 4 with insertion of the nitrogen atom into the carbon skeleton provided, after the basic work-up, 2-oxo-[1,2,4]triazolo[3,2-d][1,5]benzoxazepines 5a—5h. An unambigous structutal proof was obtained from the X-ray diffraction analysis for compound 5h.