Studies in organic mass spectrometry—IX: The fragmentation of alkylsubstituted 1,3‐cyclopentanediones

Abstract

The mass spectra of 2-and 4-substituted 1,3-~yclopentanediones are discussed. Methyl substituted compounds display mostly ring degradation, while for longer alkyl groups fragmentations in the side chain are responsible for most of the total ionization. As was found for other 1,3-diketones the spectra of 1,3-~yclopentanediones show typical and separate fragmentations for both diketoand enol-molecular ions.

Studies in organic mass spectrometry. XVII The fragmentation of methyl enol ethers of 1,3‐cyclohexanediones and 1,3‐cyclopentanediones

“…153 (9) 153 ( 4 ) ----125 (6) 125 (3) 125 ( Relative intensities between brackets. Table 2 : 2-butyl-3-methoxy-2-cyclohexenone and its deuterated homologues…”

ChemInform Abstract: STUDIES IN ORGANIC MASS SPECTROMETRY PART 17, THE FRAGMENTATION OF METHYL ENOL ETHERS OF 1,3‐CYCLOHEXANEDIONES AND 1,3‐CYCLOPENTANEDIONES

“…The origin of the hydrogen lost from ion 4 was not Scheme 3 (7) 111 (11) 111 ( 153 (9) 153 ( 4 ) ----125 (6) 125 (3) 125 ( Relative intensities between brackets. The ion 5 also ori-For 2-alkyl substituted compounds with alkyl groups longer than ethyl (IX and X) the ring bond cleavages are largely suppressed by degradation processes occurring in the side chain (scheme 3 ; n = 3).…”