26533-38-0Relevant academic research and scientific papers
PHOTOCHEMISCHE REAKTIONEN
Yoshioka, Michikazu,Ishii, Keitaro,Wolf, Hans Richard
, p. 571 - 587 (2007/10/02)
On 1n,?*-excitation (λ>347 nm) citral (5) and the methyl ketone 10 isomerize to compounds A (7, 19) and B(6, 20), whereas the phenyl ketone 11 changes into the isomer 24 of type E. evidence is given that the conversion to A and B may arise from the 3n,?*-state of the 2,6-diene-carbonyl compounds.On 1p,?*-excitation (λ=254 nm) 5 and 10 yield the isomers A (7, 19) and D (18, 22), but no products of type B.Futhermore, conversion of 10 to the isomer 21 of type C is observed.Selective 1?,?*-excitation (λ=254 nm) as well as selective 1n,?*-excitation (λ>347 nm) of the 2,7-diene-carbonyl compounds 12 and 13 give rise to isomerization to the compounds F (25, 28), exclusively.The intramolecular (2+2)-photocycloadditions are shown to be triplet processes.UV.-irradiation (λ>280 nm) of compounds F (25, 28) furnishes the isomeric products G (26, 29) which photoisomerize to oxetanes of type H (27, 30).
Process for the production of unsaturated ketones
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, (2008/06/13)
There is disclosed a process for preparing unsaturated ketones especially terpenoid ketones, by subjecting a substituted propargyl alcohol of formula (II) STR1 wherein R is a group containing 1 or 2 substituted or unsubstituted alkyl- or alkylene units containing 4 carbon atoms each to a thermal treatment sufficient to rearrange its structure in order to obtain structurally isomeric unsaturated ketones of formula I STR2 wherein one of the substituents X3 and X4 is hydrogen and the other and Z2 together form a bond. The process can be effected in the presence of an isomerization catalyst, which leads to high percentage of α.β,γ.δ-unsaturated ketones. The ketones of formula I are useful as perfumes and as intermediates for the production of terpenoid compounds.
