32917-40-1

Upstream product

• 2570-88-9 1-Oxo-2-dichlormethyl-2-methyl-cyclohexen-⁽⁵⁾ 
• 52457-01-9 3-Methylcyclohexa-1,4-diene-3-carboxylic acid 
• 699-42-3 1-methyl-2,4-cyclohexadienecarbonsaeure-methylester 

Downstream Products

• 699-42-3 1-methyl-2,4-cyclohexadienecarbonsaeure-methylester 
• 78523-44-1 1-(5-Methyl-cyclohexa-1,5-dienyl)-ethanone 
• 78523-42-9 1-(5-Methyl-cyclohexa-1,3-dienyl)-ethanone 
• 78523-43-0 1-(3-Methyl-cyclohexa-1,3-dienyl)-ethanone 
• 40572-65-4 (1-methyl-2,4-cyclohexadienyl)-methyl-keton 
• 1123-25-7 1-methyl-1-cyclohexanecarboxylic acid 

Relevant academic research and scientific papers

A Study of Gaseous Benzenium and Toluenium Ions generated from 1,4-Dihydro- and 1-Methyl-1,4-dihydro-benzoic Acids

Gaseous benzenium C6H7(1+) (1) and toluenium C7H9(1+) (2) ions have been generated by mass spectrometric loss of .CO2H from the corresponding 1,4-dihydrobenzoic acids (3) and (4), and their fragmentations after ca. 10 μs have been investigated by means of mass-analysed ion kinetic energy (MIKE) spectrometry of some 2H and 13C labelled analogues.Metastable C6H7(1+) ions eliminate H2 after proton randomization, whereas metastable C7H9(1+) ions expel both H2 and CH4 after incomplete proton equilibration.In particular, 40percent of C7H9(1+) ions randomize all their carbon and hydrogen atoms prior to loss of CH4, and 60percent of C7H9(1+) ions lose the original methyl group along with a hydrogen atom from the (proton-equilibrated) benzenium ring, accompanied by a slow and incomplete exchange between the hydrogen atoms of the ring and the methyl group.It is suggested that loss of both CH4 and H2 occur via the (ipso-)toluenium ion (2).The role of a non-classical C7H9(1+) isomer, phenylmethonium ion (6), is discussed since striking similarities are found compared * adducts from ion-molecule reactions described in the literature.

Uncatalyzed Sigmatropic 1,5-Shift of Acyl Groups in the Thermolysis of 5-Acyl-5-methyl-1,3-cyclohexadienes

Four different 5-acyl-5-methyl-1,3-cyclohexadienes 1a-d (R=COOCH3, COCH3, COC6H5, CHO) have been shown to yield mixtures of 1,3-disubstituted cyclohexadienes 2-7 and 1,3-disubstituted aromatic product 8 upon thermolysis at 150-300 deg C in solution and at 350-500 deg C in the gas phase in a flow system.Two reaction pathways are considered for the rearrangement of the C-Skeleton.For the ester 1a 13C-isotopic substitution shows that products arise to 75-86percent through a 1,5-sigmatropic shift of the methoxycarbonyl group and to 14-25percent through a sequence of reaction steps involving a 1,7-H-shift reaction in an acyclic intermediate.For the more reactive compounds 1b-d isomerization is assumed to follow the 1,5-sigmatropic pathway exclusively.A kinetic study yields the following sequence for the migration tendency of acyl groups toward sigmatropic 1,5-shift: COOCH3 COCH3 COC6H5 CHO.