2-异（口恶）唑啉等氮杂环化合物在二铬酸氢四吡啶合镍（II）氧化下的脱氢芳构化反应

研究了3，5-二芳基-4，5-二氢异（口恶）唑化合物（1a～3c)和1，3，5-三苯 基-4，5-二氢吡唑化合物（5）分别在二铬酸氢四吡啶合镍（II）[（Py)_4Ni (HCrO_4)_2]氧化下脱氢反应的结果；研究了在[(Py)_4Ni(HCrO_4)_2]存在下，吡 啶叶立德、喹啉叶立德或异喹啉叶立德分别和缺电子烯烃反应，一步法合成中氮茚 衍生物 9a～9b，11a～11b，13的结果，发现金属配合物氧化剂二铬酸氢四吡啶合 镍（II）可用于多类杂环化合物的脱氢芳构化。

Aromatizaiton of 2-Isoxazolines and Some N-Containing Heterocyclic Compounds by Tetrakis-pyridine Nickel (II) Dichromate

Aromatization of 3,5-diaryl-4,5-dihydroisoxazoles (la ~ le), 1,4- dihydropyridines (3a ~ 3c) and 1,3,5-triphenyl-4,5-dihydropyrazole (5) were promoted by tetrakis-pyridine nickel(ll) dichromate to yield the corresponding 3,5-diarylisoxazoles (2a ~ 2e) in moderate yields (52% ~ 72%), pyridine derivatives (4a ~ 4b) in moderate to high yields (79% ~ 88%) and 1,3, 5-triphenylpyrazole (6) in 81% yield, respectively. A one-pot procedure was developed to prepare the derivatives of indolizines 9a ~ 9b, lla ~ lib and 13 in moderate to high yields (84% ~ 93%) by the reaction of pyridinium JV-ylides, isoquinolinium iV- ylides or quinolinium iV-ylides with electron-deficient 8a~8b in the presence of tetrakispyridine nickel (II) dichromate (TPND). The results showed that TPND possesses very good activities on the aromatization of ^-containing heterocyclic compounds.