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Fragmentation of O-isopropylidene derivatives of 1,2-Diols on electron impact

✍ Scribed by J. -F. Rontani; C. Aubert

Publisher
John Wiley and Sons
Year
1994
Tongue
English
Weight
126 KB
Volume
29
Category
Article
ISSN
1076-5174

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✦ Synopsis

OMS Letters

Dear Sir, Fragmentation of 0-Isopropylidene Derivatives of 1,2-Diols on Electron Impact 1,3-Dioxolanes are often employed in organic synthesis to protect carbonyl groups and diols.1.2 The mass fragmentations of ethylene acetals of aldehydes and ketones have been intensively

and allowed notably the structure elucidation of unknown steroidal ketones5., On the other hand, except for the mass spectrometric characterization of positional and geometrical isomers of unsaturated fatty esters involving the use of their 0-isopropylidene derivatives,' studies concerning the fragmentation processes of 1.3- dioxolar,es deriving from aliphatic 1 ,2-diols are relatively scarce in the literature.

Recently, we identified 3-methylidene-7,11,15-trimethylhexadecane-1,2-diol among photoproducts of the isoprenoid side-chain of chlorophyll-a.8 The isopropylidene derivative of this compound ( l j presents some characteristic mass spectrometric fragmentations on electron impact [Fig. l(a)]), as reported in this paper.

Electron impact mass spectra of 0-isopropylidene deriv-

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