Porphyrins with exocyclic rings. Part 20: Synthesis and spectroscopic characterization of porphyrins with fused 2,1,3-benzoxadiazole and 2,1,3-benzoselenadiazole moieties
作者:Catherine M. Cillo、Timothy D. Lash
DOI:10.1016/j.tet.2005.09.090
日期:2005.12
base DBU to give tricyclic pyrrole derivatives in excellent yields. Further cleavage of the ester moieties and decarboxylation afforded α-unsubstituted pyrroles and these were further condensed with 2 equiv of an acetoxymethylpyrrole tert-butyl ester to give crude preparations of tripyrranes. The tert-butyl ester protective groups were cleaved with TFA and following dilution with dichloromethane, ‘3+1’
通过“ 3 + 1”麦克唐纳型方法制备具有稠合的2,1,3-苯并恶二唑和2,1,3-苯并硒二唑单元的卟啉。在非亲核试剂存在下与异氰基乙酸酯缩合的4-硝基-2,1,3-苯并恶二唑,6-氯-4-硝基-2,1,3-苯并恶二唑和4-硝基-2,1,3-苯并硒二唑用DBU碱制得三环吡咯衍生物,收率极高。酯部分的进一步裂解和脱羧得到α-未取代的吡咯,它们进一步与2当量的乙酰氧基甲基吡咯叔丁酯缩合,得到三吡喃的粗制品。该叔用TFA裂解丁酯保护基,然后用二氯甲烷稀释,用吡咯二醛“ 3 + 1”缩合,再用氯化铁氧化,以中等收率得到杂环稠合的卟啉。产率低于预期,因为由于吡咯中间体的反应性降低,难以制备所需的三吡喃。这些新的卟啉体系的紫外-可见光谱得到了高度修饰,显示出了较宽的分裂索雷特谱带。此外,镍(II),铜(II)和锌络合物具有不寻常的UV-vis光谱,具有弱的分裂Soret带和600 nm以上的强Q型吸收