222x Filetype PDF File size 1.84 MB Source: chemistry.miamioh.edu
Mass Spectrometry: Fragmentation Ethers & Sulfides ! !!!! Ethers + • M usually stronger than corresponding alcohol; may be weak/absent • α-cleavage of an alkyl radical • Inductive cleavage • Rearrangement with loss of CHR=CHR’ Aryl Ethers + • M strong • C-O cleavage β to aromatic ring with subsequent loss of CO • Cleavage adjacent to aryl ring also possible Sulfides + • M usually stronger than corresponding ether • cleavage pattern similar to ethers Mass Spectrometry: Fragmentation Ethers fragmentation patterns α-cleavage R CH O R' R + H R' 2 H O inductive cleavage R CH2 O R' R CH2 + O R' rearrangement H H H H O CH2 CHR H O H + H2C=CHR Mass Spectrometry: Fragmentation Ethers O MW = 88 ethyl propyl ether H H H O H O H m/z = 31 59 M-29 CH CH CH2CH2CH3 3 2 m/z = 43 m/z = 29 H H O M (88) 73 M-15 Mass Spectrometry: Fragmentation O Ethers MW = 130 di-sec-butyl ether H H C O H 3 m/z = 45 m/z = 57 H H3C O 101 H M-29 CH CH O H H 3 2 m/z = 59 CH3CH2 O 115 M-15 M (130)
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