1,1-Diphenyl-2-methylsulfinyl ethanol: A model compound to study the reactivity towards CNBr of a photoadduct of methionine on CγH2

Article abstract of DOI:10.1016/S0040-4039(02)01801-4

The photoadduct formed by photolysis of the [Bapa⁰, (pBzl)Phe⁵, Met(O₂)¹¹]SP/NK-1 complex localised within the T¹⁷³MP¹⁷⁵ domain of the NK-1 receptor cannot be cleaved by CNBr on the C-side of methionine; an unusual rearrangement of the intermediate sulfonium instead occurred. The reactivity of 1,1-diphenyl-2-methylsulfinyl ethanol 10 towards CNBr treatment and the stability of the 1,1-diphenyl oxirane 14 were analysed by NMR and mass spectrometry. 1,1-Diphenyl ethylene 13 can be formed from epoxide 14 even in slightly acidic conditions and during positive DCI/NH₃ mass spectrometry analysis. Altogether, these results suggest that if a covalent linkage between the [Bapa⁰, (pBzl)Phe⁵, Met(O₂)¹¹] and the NK-1 receptor occurred on the C_γH₂ of methionine-174, CNBr treatment will lead to an epoxide/ketone and an ethylenic compound.