24323-24-8Relevant academic research and scientific papers
Preparation method of carboxylic acid compound
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Paragraph 0113; 0156-0158, (2017/08/29)
The invention provides a preparation method of a carboxylic acid compound. The preparation method comprises the following step of taking a lactone component to react with hydrogen in the presence of a compound catalyst to obtain the carboxylic acid compound. The compound catalyst comprises a hydrogenation catalyst and Lewis acid. In the presence of the compound catalyst comprising the hydrogenation catalyst and the Lewis acid, the lactone component is subjected to hydrogenation ring-opening reaction to obtain the carboxylic acid compound. The preparation method has the advantages of moderate reaction conditions and high yield; compared with a traditional method, less byproducts are generated, green and chemical requirements are met and the industrial value is better.
A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
, p. 7520 - 7528 (2017/11/10)
Direct hydrogenolysis of lactone to carboxylic acid (i.e., hydrogenolysis of the Calkoxy-O bond with the carbonyl group untouched) is generally difficult, as the current strategies employing Br?nsted acids as the catalyst usually require harsh conditions such as a high temperature and a high H2 pressure. Herein, we report a developed solvent-free catalytic transformation, in which W(OTf)6 is believed to promote the hydrogenolysis process. This strategy could efficiently hydrogenate lactones to carboxylic acids under extra mild conditions (e.g., a reaction temperature of 2) and showed a broad substrate scope. In addition, the catalytic protocol can be further applied to the hydrogenolysis of polyhydroxyalkanoate, as a renewable polymer, to the corresponding straight-chain carboxylic acids. An extensive mechanistic study was subsequently performed, and the density functional theory calculations revealed a reaction pattern, including the complete cleavage of the C=O bond with the assistance of the W(OTf)6 catalyst. Moreover, the key intermediate created in the mechanism, as an oxonium with an OTf moiety, was successfully detected by electrospray ionization mass spectra. Through a comparison with the Br?nsted acid-catalyzed system, the study confirmed that the existence of the OTf moiety can significantly lower the barriers associated with the rearrangement and elimination processes. Meanwhile, emphasis was placed on the critical role that the anion plays, as well as the fact that the anion effect is directly related to the chemoselectivity.
Do enzymes recognise remotely located stereocentres? Highly enantioselective Candida rugosa lipase-catalysed esterification of the 2- to 8-methyldecanoic acids
Hedenstroem, Erik,Nguyen, Ba-Vu,Silks III, Louis A.
, p. 835 - 844 (2007/10/03)
Several racemic methyl decanoic acids have been synthesised and successfully resolved in esterification with 1-hexadecanol at aw=0.8 in cyclohexane using immobilised Candida rugosa lipase (CRL) as the catalyst. The enantiomeric ratios (E=2.8-68) obtained were surprisingly high even when the methyl group was as remotely located as in 8-methyldecanoic acid (E=25). Interestingly, the lipase shows enantiopreference for the S-enantiomer when the methyl group is located on even numbered carbons i.e. for the 2-,4-,6- and 8-methyldecanoic acids and to the R-enantiomer when the methyl group is located on uneven numbered carbons i.e. for the 3-,5- and 7-methyldecanoic acids.
Unusual Fatty Acids with Specific Odor from Mature Male Goat
Sugiyama, Takeyoshi,Sasada, Hiroshi,Masaki, Junji,Yamashita, Kyohei
, p. 2655 - 2658 (2007/10/02)
Unusual five 4-ethyl-fatty acids were estimated as main constituents of sebaceous gland secretion of male goat which showed the releaser pheromone activity against the estrous female.These acids exist in both free state and ester form.The structures were confirmed by synthesis.Among the five acids, 4-ethyloctanoic acid showed the strong goaty odor at low concentration.
