4698-08-2Relevant academic research and scientific papers
Method for preparing geranic acid by oxidizing citral
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Paragraph 0035-0070, (2021/01/24)
The invention provides a method for preparing geranic acid by oxidizing citral. The method comprises the following step: with a metal active component and a hydroxyl-containing azacyclo-ligand as catalysts and oxygen-containing gas as an oxidant, catalyzing citral to undergo an oxidation reaction so as to prepare the geranic acid. According to the method, the hydroxyl-containing azacyclo-ligand isadopted as a ligand, metal manganese, cobalt or copper and the like are adopted as active metals, oxidation depth is controlled, and the generation of oxidation byproducts is reduced, so the selectivity of the main product geranic acid is guaranteed, and unreacted citral is recycled. According to the method, a large amount of citral which is easy to obtain serves as a starting material, oxygen-containing gas such as air serves as a clean oxidizing agent, and the geranic acid is obtained through one-step catalytic oxidation, so a synthesis route is short, yield is high, and cost advantage is good.
Highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(iii) catalyst and CO2
Han, Sheng,Wang, Ying,Wei, Yongge,Wu, Zhikang,Yu, Han
, p. 3150 - 3154 (2020/06/19)
Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes.
Amides as bioisosteres of triazole-based geranylgeranyl diphosphate synthase inhibitors
Goetz, Daniel B.,Holstein, Sarah A.,Varney, Michelle L.,Wiemer, David F.
, (2020/07/10)
Geranylgeranyl diphosphate synthase (GGDPS) inhibitors are of potential therapeutic interest as a consequence of their activity against the bone marrow cancer multiple myeloma. A series of bisphosphonates linked to an isoprenoid tail through an amide linkage has been prepared and tested for the ability to inhibit GGDPS in enzyme and cell-based assays. The amides were designed as analogues to triazole-based GGDPS inhibitors. Several of the new compounds show GGDPS inhibitory activity in both enzyme and cell assays, with potency dependent on chain length and olefin stereochemistry.
Divergent synthesis of four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid, esters and evaluation for the antifungal activity
Wang, Weiwei,Zhang, Xiaoteng,Zhao, Yu,Liu, Xinlei,Zhang, Zhenhua,Wang, Mingan
, (2018/03/12)
The four isomers of 6,7-dihydroxy-3,7-dimethyloct-2-enoic acid 2 were synthesized via the selective direct Sharpless asymmetry dihydroxylation of geraniol as the key step in 35.0%-48.0% overall yields with 91.9%-97.7% ee values for esters 4 and 31.3%-36.4% overall yields with 90.3-97.5% ee values for acids 2 using cis- and trans-geraniol as raw materials. Their structures were characterized by 1H, 13C NMR and HR-ESI-MS data. The in vivo bioassay results showed that the chiral acid (Z, S)-2 was a good lead compound with 80%-100% inhibitory rates against P. cubensis, E. graminis, P. sorghi and C. gloeosporioides at the concentration of 400μg/mL.
Heterologous expression of geraniol dehydrogenase for identifying the metabolic pathways involved in the biotransformation of citral by Acinetobacter sp. Tol 5
Usami, Atsushi,Ishikawa, Masahito,Hori, Katsutoshi
, p. 2012 - 2020 (2018/11/06)
The biotransformation of citral, an industrially important monoterpenoid, has been extensively studied using many microbial biocatalysts. However, the metabolic pathways involved in its biotransformation are still unclear, because citral is a mixture of the trans-isomer geranial and the cis-isomer neral. Here, we applied the heterologous expression of geoA, a gene encoding geraniol dehydrogenase that specifically converts geraniol to geranial and nerol to neral, to identify the metabolic pathways involved in the biotransformation of citral. Acinetobacter sp. Tol 5 was employed in order to demonstrate the utility of this methodology. Tol 5 transformed citral to (1R,3R,4R)-1-methyl-4-(1-methylethenyl)-1,3-cyclohexanediol and geranic acid. Biotransformation of citral precursors (geraniol and nerol) by Tol 5 transformant cells expressing geoA revealed that these compounds were transformed specifically from geranial. Our methodology is expected to facilitate a better understanding of the metabolic pathways involved in the biotransformation of substrates that are unstable and include geometric isomers.
Nitrous Oxide as a Hydrogen Acceptor for the Dehydrogenative Coupling of Alcohols
Gianetti, Thomas L.,Annen, Samuel P.,Santiso-Quinones, Gustavo,Reiher, Markus,Driess, Matthias,Grützmacher, Hansj?rg
supporting information, p. 1854 - 1858 (2016/02/03)
The oxidation of alcohols with N2O as the hydrogen acceptor was achieved with low catalyst loadings of a rhodium complex that features a cooperative bis(olefin)amido ligand under mild conditions. Two different methods enable the formation of either the corresponding carboxylic acid or the ester. N2 and water are the only by-products. Mechanistic studies supported by DFT calculations suggest that the oxygen atom of N2O is transferred to the metal center by insertion into the Rh-H bond of a rhodium amino hydride species, generating a rhodium hydroxy complex as a key intermediate.
Synthesis and fungicidal activities of (Z/E)-3,7-dimethyl-2,6-octadienamide and its 6,7-epoxy analogues
Yang, Mingyan,Dong, Hongbo,Jiang, Jiazhen,Wang, Mingan
, p. 21023 - 21036 (2016/01/25)
In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl- 2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and 1H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 μg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC50 values of 4.3 and 9.7 μM against Fusahum graminearum and R. Solani, respectively.
Selective catalytic oxidation of geraniol to citral with molecular oxygen in supercritical carbon dioxide
Dapurkar, Sudhir E.,Kawanami, Hajime,Chatterjee, Maya,Rode, Chandrasekhar V.,Yokoyama, Toshirou,Ikushima, Yutaka
experimental part, p. 209 - 214 (2012/01/06)
Selective catalytic oxidation of geraniol to citral with molecular oxygen in supercritical carbon dioxide (scCO2) has been investigated. The catalyst used was a chromium containing mesoporous molecular sieve catalyst viz. CrMCM-41. Comparison studies were performed with CoMCM-41, PtMCM-41 and PdMCM-41 catalysts. Among the various catalysts studied, CrMCM-41 showed a high conversion of geraniol and an excellent selectivity for citral. In contrast CoMCM-41, PtMCM-41 and PdMCM-41 catalysts exhibited low conversion of geraniol. However all three catalysts compared showed similar citral selectivity to CrMCM-41. The effect of CO2 pressure and reaction temperature geraniol oxidation was studied with CrMCM-41. Supercritical CO2 medium was found to enhance the conversion of geraniol and/or yield of citral. It was noticed that the catalyst can be recycled with negligible loss of conversion.
Method for preparing an unsaturated carboxylic acid
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Page/Page column 4; 5, (2008/06/13)
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
Alcohols oxidation with hydrogen peroxide promoted by TPAP-doped ormosils
Campestrini, Sandro,Carraro, Massimo,Ciriminna, Rosaria,Pagliaro, Mario,Tonellato, Umberto
, p. 7283 - 7286 (2007/10/03)
Organically modified silica gels doped with TPAP (tetra-n-propylammonium perruthenate) are effective catalysts for the oxidation of alcohols by hydrogen peroxide at room temperature, provided that the oxidant H2O 2 solution is added slowly. The effect of the surface catalyst polarity is the opposite of that found in aerobic alcohols oxidation and is consistent with the polar nature of the primary oxidant.
