Water → HCID 68124900, Verbindung
Reaktionsgleichung
[CH:1](/[C:9]1[N:13]=[CH:12][O:11][N:10]=1)=[CH:2]\[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.O>C(O)C.[Hg]>[CH:1](/[C:9]1[N:13]=[CH:12][O:11][N:10]=1)=[CH:2]/[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1Komponenten
5
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 2
Versuchsvorschrift
3-(trans-Styryl)-1,2,4-oxadiazole (0.75 g.) in absolute ethanol (750 ml.) was irradiated at room temperature, under nitrogen for a total of 31 hr. using a medium pressure mercury vapour arc tube contained in a water cooled glass well immersed in the solution. The ultraviolet spectra of suitably diluted aliquots showed a reduction in the intensity of absorption at ca. 274 nm over the period of irradiation. The colourless solution was evaporated to a low volume when the trans isomer (0.11 g.), m.p. 84° , λmax. (EtOH) 274 nm (ε 26,200) separated. Evaporation of the mother liquors to dryness gave a solid and an oil. The oil was separated and thoroughly dried to give 3-(cis-styryl)-1,2,4-oxadiazole contaminated with ca. 25% by weight of the trans-isomer, λmax. (EtOH) 272-273 nm (ε 14,300), pmr. shows cis-protons at 2.92 and 3.50 (J = 12.5) and confirms the presence of the transisomer.