The ring-photoisomerization of 3-amino- and 3-methylamino-5-phenyl-1,2,4-oxadiazoles into the corresponding 2-amino- and 2-methylamino-5-phenyl-1,3,4-oxadiazoles has been reinvestigated by examining the effect of a base on the photoreaction. On irradiating at λ = 254 nm in methanol, yields of the ring-photoisomers were found to be significantly enhanced by the addition of triethylamine (TEA) in the
已经将3-
氨基-和3-甲基
氨基-5-苯基-
1,2,4-恶二唑的环光异构化为相应的2-
氨基-和2-甲基
氨基-5-苯基-1,3,4-恶二唑。通过研究碱对光反应的影响进行了重新研究。在
甲醇中以λ= 254 nm进行辐照时,发现通过在光反应介质中添加
三乙胺(
TEA),可以显着提高环状光异构体的收率。相比之下,在含
TEA的
乙腈中辐照3-
氨基-5-苯基恶二唑几乎可以将光完全还原为苯甲酰
胍,而仅检测到百分之几的环状光异构体。此外,在含
三乙胺的
乙腈中the敏感的3-
氨基-5-苯基恶二唑的光解也得到了苯甲酰基
胍,但没有痕量的环状光异构体。