Question

(34)The mass spectra of acid derivatives follow the principles shown for other carbonyl compounds and for alkoxy groups. Both McLafferty rearrangements and alpha-cleavages are common. The mass spectrum for butyl butanoate shows two prominent even-mass fragments at m/z 88 and m/z 60. Propose structures for these two fragments, and show what fragmentations produce them.

Answer 1

34. un Butyl butanoate, mut: 144 mart: 144 mlz=144 ar mc Lafferty 1 tot B Rearrangement N = Hemo cleavage mz-88 2nd ri To o ni mclafferty OH -OH 5H + 11 & Rearrangeret malz= 88 m/z=60 mclafferty TOH n tl Rearrangemed ro m/z=116 Mlz=144 2nd mclafferty oH 2 Hota H A Rearrangeret miz=116 m/2=60 melafferty effect: The molecule contains a coto-group undergo ß- clearage, with the gain of g- hydrogen atom called me lafferty Rearrangement.