Studies on amino acid derivatives. V. Synthesis of pyridobenzazoles.
作者:TAKUO CHIBA、TAKUMI TAKAHASHI、CHIKARA KANEKO
DOI:10.1248/cpb.33.4002
日期:——
Ethyl 2-benzimidazoleacetate (2a) reacted with 4-ethoxymethylene-2-phenyl-5-oxazolone (1) to give 2-benzamido-4-ethoxycarbonyl-1-oxo-1, 5-dihydropyrido [1, 2-α] benzimidazole (5a). Similar reactions of ethyl 2-benzoxazoleacetate (3a) or ethyl 2-benzothiazoleacetate (4a) with compound 1 gave the corresponding pyridobenzazoles, i.e., pyrido [2, 1-b] benzoxazole (6a) and pyrido [2, 1-b]-benzothiazole (7a), respectively. 2-Cyanomethyl-(2b, 3b, and 4b) and 2-acetonyl-benzazole derivatives (2c, 3c, and 4c), if used in the above reactions instead of 2-ethoxycarbonyl derivatives (2a, 3a, and 4a), gave the corresponding pyridobenzazole derivatives (5b, 6b, 7b, 5c, 6c, and 7c).
乙基2-苯并咪唑乙酸酯(2a)与4-乙氧亚甲基-2-苯基-5-恶唑酮(1)反应,生成2-苯甲酰胺基-4-乙氧羰基-1-氧代-1,5-二氢吡啶并[1,2-α]苯并咪唑(5a)。类似的反应中,乙基2-苯并恶唑乙酸酯(3a)或乙基2-苯并噻唑乙酸酯(4a)与化合物1反应,分别得到相应的吡啶并苯并恶唑(6a)和吡啶并苯并噻唑(7a)。若在上述反应中使用2-氰甲基(2b、3b和4b)或2-丙酮基苯并唑衍生物(2c、3c和4c)代替2-乙氧羰基衍生物(2a、3a和4a),则得到相应的吡啶并苯并唑衍生物(5b、6b、7b、5c、6c和7c)。