Studies in photochemistry. Part V. The photocyclodehydrogenation of 2-furyl- and 2-thienyl-ethylenes: the mass spectra of the products

Abstract

Photochemical cyclodehydrogenation of 2-styrylfuran, 1,2-di-(2-furyl)ethylene, 1-(2-furyl)-2-(2-thienyl)-ethylene, and 1,2-di-(2-thienyl)ethylene gave naphtho[2,1-b]furan, benzo[1,2-b:4,3-b′]difuran, thieno[3,2-e]-benzofuran, and benzo[1,2-b:4,3-b′]dithiophen, respectively. The mass spectra of the reaction products are reported and interpretations given for the formation of the various fragment ions. The ultraviolet spectra are recorded.