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

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5a～5g.

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

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 KMnO4. Compounds 3 were allowed to react with HBF4, 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]triazolo3,2-d]1,5]benzoxazepines 5a—5h. An unambigous structutal proof was obtained from the X-ray diffraction analysis for compound 5h.