- Method for preparing an unsaturated carboxylic acid
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The invention concerns a method for preparing an unsaturated carboxylic acid from the corresponding aldehyde. More particularly, the invention aims at preparing an aliphatic carboxylic acid having at least an unsaturation conjugated with the carbonyl group. In particular, the invention concerns the preparation of geranic acid. The invention relates to a method for preparing an unsaturated carboxylic acid from the corresponding aldehyde. Said method is characterized in that it comprises a step which consists in oxidizing said aldehyde, in controlled basic medium and using molecular oxygen or a gas containing same, in the presence of a catalyst based on palladium and/or platinum and an activator based on bismuth, in conditions such that the oxidizing is carried out by diffusion process
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Page/Page column 4; 5
(2008/06/13)
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- Hydroxy-assisted Chemo- and Stereo-selective Epoxidation Catalysed by a Titanium Silicate Molecular Sieve (TS-1)/H2O2 System
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The TS-1/H2O2 system efficiently catalyses the hydroxy-assisted chemoselective epoxidation of α-hydroxyalkene in geraniol, and the stereoselective epoxidation of cyclopent-2-en-1-ol/cyclohex-2-en-1-ol producing the epoxide which is cis to OH with high selectivity (90:10 cis:trans).
- Kumar, Rajiv,Pais, Godwin C. G.,Pandey, Bipin,Kumar, Pradeep
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p. 1315 - 1316
(2007/10/02)
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- ACTIVATION AND SYNTHETIC APPLICATION OF THIOSTANNANES. PROTECTION OF CARBOXYL GROUPS WITH α-METHYLCINNAMYL ALCOHOL AS A MEANS OF CHEMODIFFERENTIATION AND SELECTIVE ACTIVATION
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α-Methylcinnamyl (MEC) esters are converted into parent carboxylic acids under mild conditions, various functions being tolerated including acetoxy, siloxy, MEM, and so on.Furthermore, MEC esters are transformed into other esters through CsF-promoted alkylation of intermediary organotin carboxylates.
- Sato, Tsueno,Otera, Junzo,Nozaki, Hitoshi
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p. 2959 - 2962
(2007/10/02)
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- Reaction of Diketene with Grignard Reagents in the Presence of Cobalt Catalyst. A Convenient Method for the Synthesis of 3-Methylenealkanoic Acids Leading to Terpenoids
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Primary alkyl Grignard reagents react regioselectively with diketene in the presence of cobalt(II) iodide to afford 3-methylenealkanoic acids in good yields.The synthetic utility of this reaction is demonstrated in the syntheses of terpenoids by two methods.Utilizing the isomerization of double bond of 3-methylenealkanoic acids, geranic acid and farnesic acid were obtained in two steps.Another method, the tandem sigmatropic rearrangement of the corresponding allylic esters was used for the synthesis of C18-Cecropia juvenile hormone.
- Fujisawa, Tamotsu,Sato, Toshio,Gotoh, Yoshihiko,Kawashima, Masatoshi,Kawara, Tatsuo
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p. 3555 - 3559
(2007/10/02)
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