Photochemical approach to the synthesis of naturally occurring thienylacetylenes
作者:Maurizio D'Auria、Daniela Tofani
DOI:10.1016/s0040-4020(01)85621-0
日期:1992.1
Three naturallyoccurring thienylacetylenes are synthesized through a photochemical coupling of 5-iodo-2-thienyl derivatives and 5-trimethylsilyl-2-thienylacetylene.
Synthesis and photochemical properties of 1-aryl-4-nitroimidazoles are described. These compounds are good sensitizers of superoxide ion. Only 1-phenyl-2-methyl-4-nitroimidazole is a photosensitizer of singlet oxygen.
A convincing evidence of the ability of the coloured open forms or photomerocyanines of photochromic compounds to act as sensitiser of singlet oxygen is provided by photosensitised oxidation of reference olefins, cis- and trans-α,α′-dimethylstilbenes, to a hydroperoxide.
Tandem Photoarylation-Photoisomerization of Halothiazoles: Synthesis, Photophysical and Singlet Oxygen Activation Properties of Ethyl 2-Arylthiazole-5-carboxylates
reaction between ethyl 2-chlorothiazole-5-carboxylate and benzene gave no product. In contrast, the reaction with ethyl 2-iodothiazole-5-carboxylate gave ethyl 3-phenylisothiazole-4-carboxylate. The same behaviour was observed if the reaction was performed in the presence of furan, thiophene and 2-bromothiophene. The products thus obtained were studied for their photophysicalproperties and it was found
2-氯噻唑-5-羧酸乙酯和苯之间的光化学反应没有产生产物。相反,与2-碘噻唑-5-羧酸乙酯的反应得到3-苯基异噻唑-4-羧酸乙酯。如果反应在呋喃、噻吩和 2-溴噻吩的存在下进行,则观察到相同的行为。研究了由此获得的产物的光物理性质,发现 3-苯基异噻唑-4-羧酸乙酯的观察吸收 [λ max =257 nm (e = 7000 M -1 cm -1 ),278 nm (e = 7000 M -1 cm -1 ) 对于 3-(2-furyl)isothiazole-4-carboxylate 乙酯,269 和 285 nm (e = 7500 M -1 cm -1 ) 对于 3-(2-thienyl)isothiazole-4 乙酯-羧酸盐]主要是由于从 HOMO 到 LUMO+1 轨道的 π→π* 跃迁。测试化合物显示荧光 [λ em = 350-400 (λ exc = 300 nm), 360
D'Auria, Maurizio; Mauriello, Giacomo, Photochemistry and Photobiology, 1994, vol. 60, # 6, p. 542 - 545