116997-30-9Relevant academic research and scientific papers
Thermal Decomposition of 3,3,5-Trisubstituted-4,4-dimethyl-4,5-dihydro-5-hydroperoxy-3H-pyrazoles: Route to β,γ-Unsaturated Ketones
Baumstark, Alfons L.,Vasquez, Pedro C.
, p. 113 - 117 (2007/10/02)
The thermal decomposition of a series of cyclic α-azo hydroperoxides (3,3,5-R1, R2, R3-4,4-dimethyl-4,5-dihydro-5-hydroperoxy-3H-pyrazoles; 2a R1 = R2 = R3 = Ph; 2b R1= R3 = Ph, R2 = Me; 2c R1 = R3 = p-Anisyl, R2 = Me; 2d R1 = R2 = Me, R3 = Ph; 2e R1 = R3 = Me, R2 = Ph), synthesized by oxidation of the corresponding 3,4-dihydro-2H-pyrazoles, proceeded smoothly with evolution of nitrogen.The relative stability series was found to be 2a > 2c ca. 2b > 2d > 2e.For 2a, the products were 1,4,4-triphenyl-2,2-dimethylpropanone and 1,1-dimethyl-2,2-diphenylethylene.For 2b-e,m β,γ-unsaturated ketones were obtained as the major products in ca. 60percent yield from the thermolyses.The products are consistent with a free-radical mechanism involving initial homolysis of the O-O bond followed by loss of nitrogen to yield a free-radical beta to the carbonyl group.For 2a, β-scission and hydrogen-atom abstraction of the hydroperoxy proton by the β-keto radical (induced decomposition) are the major pathways leading to products.For 2b-c, abstraction of a γ-hydrogen atom of the β-keto radicals by hydroxy radical accounts for the formation of the β,γ-unsaturated compounds as the major product.
Photochemical Reactions of Arenecarboxylic Acid Esters with Electron-Rich Alkenes: 2 + 2 Cycloaddition, Hydrogen Abstraction, and Cycloreversion
Cantrell, Thomas S.,Allen, Andrew C.
, p. 135 - 139 (2007/10/02)
The photochemical reaction of arenecarboxylic acid methyl esters and isopropyl esters with alkenes has been examined and found to afford three types of products: (a) 2-alkoxyoxetanes 3 via a direct 2 + 2 cycloaddition to the substrate alkenes; (b) β,γ-unsaturated ketones 5 via hydrogen abstraction by the carbonyl oxygen of the photoexcited ester from an allylic position of the substrate alkene; and (c) alkoxyalkenes 4, which arise via 2 + 2 cycloreversion of the oxetanes 3.The quantum yields for the formation of the various products generally fell in the range 0.005-0.03, approximately 1 order of magnitude less than those of aryl ketones and aldehydes undergoing similar reactions.
