title: Photolysis of 3-aryl-3-(trifluoromethyl)diazirines: a caveat regarding their use in photoaffinity probes.
abstract: The photolysis of 3-(4-tolyl)-3-(trifluoromethyl)diazirine in the presence of benzene, methanol, carbon tetrachloride, cyclohexane, triethylsilane, or diethylamine led to photoproducts consistent with the intermediacy of a singlet carbene. In the case of diethylamine, the photoinsertion into the N-H bond of diethylamine produced the expected adduct, 1-(diethylamino)-2,2,2-trifluoro-1-(4-tolyl)ethane. However, the base-catalyzed elimination of hydrogen fluoride from this adduct afforded an enamine, alpha-(diethylamino)-beta,beta-difluoro-4-methylstyrene, and the subsequent hydrolysis of this enamine furnished diethylamine and 2,2-difluoro-1-(4-tolyl)ethanone. This elimination and hydrolysis sequence effectively reversed the photoinsertion process. A similar photoinsertion and hydrolysis process using 3-(4-n-octylphenyl)-3-(trifluoromethyl)diazirine also produced 2,2-difluoro-1-(4-n-octylphenyl)ethanone in modest yield. These results suggest that the photoinsertion products from 3-aryl-3-(trifluoromethyl)-diazirines in biological systems may suffer similar fates limiting, in part, their utility in obtaining primary sequence data.
authors.affiliation: Department of Chemistry, Ohio State University, Columbus 43210.
authors.forename: M
authors.initials: M
authors.lastname: Platz
authors.forename: A S
authors.initials: AS
authors.lastname: Admasu
authors.forename: S
authors.initials: S
authors.lastname: Kwiatkowski
authors.forename: P J
authors.initials: PJ
authors.lastname: Crocker
authors.forename: N
authors.initials: N
authors.lastname: Imai
authors.forename: D S
authors.initials: DS
authors.lastname: Watt
mesh_terms: D000345:Affinity Labels; D001389:Azirines / Q000737:chemistry*; D010782:Photolysis
chemical_list: D000345:Affinity Labels; D001389:Azirines; C073104:3-(4-tolyl)-3-(trifluoromethyl)diazirine