F:Flammable;
57-11-4Relevant articles and documents
The phytochemical investigation of five African Croton species: Croton oligandrus, Croton megalocarpus, Croton menyharthii, Croton rivularis and Croton megalobotrys
Langat, Moses K.,Djuidje, Elvire F.K.,Ndunda, Beth M.,Isyaka, Sani M.,Dolan, Nathalie S.,Ettridge, Gareth D.,Whitmore, Hannah,Lopez, Isabel,Alqahtani, Alaa M.,Atiku, Ibrahim,Lobe, Jules S.,Mas-Claret, Eduard,Crouch, Neil R.,Midiwo, Jacob O.,Mulholland, Dulcie A.,Kamdem, Alain F.W.
, p. 148 - 155 (2020)
The chemistry of five African Croton taxa, Croton oligandrus Pierre ex Hutch., Croton megalocarpus Hutch., Croton menyharthii Pax, Croton rivularis Mull.Arg. and Croton megalobotrys Mull.Arg. is described. The undescribed ent-19-hydroxyisopimara-8(9),15-dien-7-one and ent-isopimara-7(8),15-dien-16,19-diol were isolated from the fruits of C. oligandrus, ent-isopimara-7(8),15-dien-19-yl octadecanoate was obtained from both the fruits and leaves, and ent-19-hydroxyisopimara-8(9),15-dien-7-one was isolated from the leaves of this species. The undescribed 3,4,15,16-diepoxy-8α-hydroxycleroda-13(16),14-dien-12S,17-olide and (5S,9R,10S)-7,13-ent-abietadien-2-one were isolated from the leaves and roots of C. megalocarpus respectively. Compounds isolated from C. menyharthii, C. rivularis and C. megalobotrys have been reported from other sources. The structures of the compounds were determined using NMR, IR and MS experiments. The absolute configurations of the ent-isopimarane, ent-abietane and ent-clerodane diterpenoids isolated were confirmed by comparing calculated and experimental electronic circular dichroism (ECD) spectra. DP4+ probability calculations were used to assign the configuration at C-8 for 3,4,15,16-diepoxy-8α-hydroxycleroda-13(16),14-dien-12S,17-olide. Epoxy-ent-clerodadiene, 3β,4β:15,16-diepoxy-13(16),14-ent-clerodadien-17,12S-olide, 3β,4β:15,16-diepoxy-8α-hydroxy-ent-cleroda-13(16),14-dien-12,17-olide, 7,13-abietadien-2-ol, (5S,9R,10S)-7,13-ent-abietadien-2-one, crotonolide E, furocrotinsulolide A, epoxychiromodine, 3β,4β:15,16-diepoxy-13(16),14-ent-clerodadiene and crotohalimaneic acid were selected for screening based on their ability to add diversity to the NCI small molecule compound collection, and were evaluated against the NCI60 panel of human tumour cell lines at 10μM level, but found inactive.
Anti-diabetic potential of ursolic acid stearoyl glucoside: A new triterpenic gycosidic ester from Lantana camara
Kazmi, Imran,Rahman, Mahfoozur,Afzal, Muhammad,Gupta, Gaurav,Saleem, Shakir,Afzal, Obaid,Shaharyar, Md.Adil,Nautiyal, Ujjwal,Ahmed, Sayeed,Anwar, Firoz
, p. 142 - 146 (2012)
A new stearoyl glucoside of ursolic acid, urs-12-en-3β-ol-28-oic acid 3β-d-glucopyranosyl-4′-octadecanoate and other compounds were isolated from the leaves of Lantana camara L. The structure of this new glycoside was elucidated and established by standard spectroscopic methods. In streptozotocin-induced diabetic rats it showed significant reduction in blood glucose level. Crown Copyright
Hydrothermal catalytic processing of saturated and unsaturated fatty acids to hydrocarbons with glycerol for in situ hydrogen production
Vardon, Derek R.,Sharma, Brajendra K.,Jaramillo, Humberto,Kim, Dongwook,Choe, Jong Kwon,Ciesielski, Peter N.,Strathmann, Timothy J.
, p. 1507 - 1520 (2014)
Lipids are a promising feedstock to produce renewable hydrocarbon fuels and H2via catalytic hydrothermal processing. Upon exposure to hydrothermal media (e.g., 300 °C, 8-11 MPa), lipids rapidly hydrolyze to produce saturated and unsaturated free fatty acids in varying ratios, depending on the feedstock, as well as glycerol. This report demonstrates the potential of Pt-Re/C for the hydrothermal conversion of saturated and unsaturated fatty acids to hydrocarbons, using glycerol reforming for in situ H2 production to meet process demands. Experiments showed that deoxygenation of stearic acid, a model saturated fatty acid, was significantly enhanced with Pt-Re/C under a reducing atmosphere compared to Pt/C. The coupled hydrogenation and deoxygenation (HYD-DOX) of oleic aid, a model unsaturated fatty acid, was also moderately enhanced under an inert atmosphere using glycerol for in situ H2 production, with DOX as the rate-limiting step. Characterization of Pt-Re/C showed that Re had a significant effect on CO:H uptake ratio (2.2) compared to commercial Pt/C (1.3), with the metals dispersed as small crystallites (～3-4 nm) throughout carbon support. Experiments revealed that the initial system H2 headspace loading 2 consumption. At higher initial H2 loadings (≥3.45 MPa), fatty acid reduction was also observed as a minor DOX pathway. Experiments also showed that oleic acid HYD-DOX and glycerol reforming are affected by initial glycerol concentration and catalyst loading. Under optimized process conditions, complete HYD-DOX of oleic acid to heptadecane was achieved within 2 h with a net-zero H2 consumption using a 1:3 glycerol-to-fatty acid ratio (i.e., the native ratio in triacylglycerides). X-ray photoelectron spectroscopy showed that H2 in the reactor headspace results in lower oxidation states of Pt and Re, suggesting a possible mechanism for enhanced DOX kinetics. This approach holds promise for overcoming the high external H 2 demands of conventional lipid hydrotreatment processes.
ALL-CIS-3,6,9,12,15-OCTADECAPENTAENOIC ACID: A PROBLEM OF RESOLUTION IN THE GC ANALYSIS OF MARINE FATTY ACIDS
Napolitano, G. E.,Ratnayake, W. M. N.,Ackman, R. G.
, p. 1751 - 1756 (1988)
The GC properties of 18:5n3 (all-cis-3,6,9,12,15-octadecapentaenoic acid) of algal origin are described for analysis on the popular polyglycol liquid phase Carbowax-20M "bonded" in flexible fused silica open-tubular columns.It is shown with oyster lipids that this fatty acid could be confused with early eluting 20:1 isomers such as the 20:1n11, common in marine animal oils and lipids, and coincides exactly with 20:1n15 of plant origin.Partial hydrazine reduction is demonstrated as a useful technique for confirming the structure of 18:5n3.Key Word Index-Octadecapentaenoic acid; gas-liquid chromatography; phytoplankter fatty acids; marine lipids; hydrazine reduction.
Practical scale up synthesis of carboxylic acids and their bioisosteres 5-substituted-1H-tetrazoles catalyzed by a graphene oxide-based solid acid carbocatalyst
Mittal, Rupali,Kumar, Amit,Awasthi, Satish Kumar
, p. 11166 - 11176 (2021/03/31)
Herein, catalytic application of a metal-free sulfonic acid functionalized reduced graphene oxide (SA-rGO) material is reported for the synthesis of both carboxylic acids and their bioisosteres, 5-substituted-1H-tetrazoles. SA-rGO as a catalytic material incorporates the intriguing properties of graphene oxide material with additional benefits of highly acidic sites due to sulfonic acid groups. The oxidation of aldehydes to carboxylic acids could be efficiently achieved using H2O2as a green oxidant with high TOF values (9.06-9.89 h?1). The 5-substituted-1H-tetrazoles could also be effectively synthesized with high TOF values (12.08-16.96 h?1). The synthesis of 5-substituted-1H-tetrazoles was corroborated by single crystal X-ray analysis and computational calculations of the proposed reaction mechanism which correlated well with experimental findings. Both of the reactions could be performed efficiently at gram scale (10 g) using the SA-rGO catalyst. SA-rGO displays eminent reusability up to eight runs without significant decrease in its productivity. Thus, these features make SA-rGO riveting from an industrial perspective.
Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
, p. 1949 - 1960 (2021/03/26)
Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
Identification and α -Glucosidase Inhibitory Activity of Meroterpenoids from Hericium erinaceus
Bao, Li,Chen, Baosong,Han, Junjie,Liu, Hongwei,Ma, Ke,Wang, Wenzhao
, p. 571 - 578 (2020/06/03)
Hericium erinaceus is a very popular edible and medicinal mushroom used for the treatment of enervation and gastrointestinal diseases in Eastern Asia. Chemical investigation on the fruiting body of Hericium erinaceus led to the isolation of 4 new (1 - 4) and 10 known meroterpenoids (5 - 14). The structures of new compounds were determined via analysis of NMR and MS data in combination with chemical derivatization. The inhibitory activities of 1 - 14 against α -glucosidase were evaluated using p -nitrophenyl- α -D-glucopyranoside, sucrose, or maltose as substrate. Compounds 6, 9, 11 - 13 were demonstrated to show the α -glucosidase inhibitory activities. This work confirms the potential of H. erinaceus in the treatment of diabetes.
Homogeneous catalytic hydrogenation of lipids in aqueous dispersions and bacterial cell membranes with an efficient water-soluble Pd(II)-sulfosalan catalyst, Na2[Pd(HSS)]
Bunda, Szilvia,Gombos, Réka,Joó, Ferenc,Nagyházi, Brigitta
, (2020/09/17)
The recently synthesized water-soluble Na2[Pd(HSS)] (Na2HSS = hydrogenated sulfonated salen) was shown to be a non-toxic, active catalyst for modification of model and biomembranes by homogeneous catalytic hydrogenation. Hydrogenation of the unsaturated fatty acyl residues in soy-bean lecithin liposomes and in biomembranes of intact Pseudomonas putida F1 cells was accompanied by substantial cis-trans isomerization around the C[dbnd]C double bonds. The hydrogenations could be run in aqueous media under mild conditions (25 °C, 1 bar H2). Partial saturation (up to 10% conversion) of the membrane lipids of P. putida F1 did not damage the cells.
Catalytic transfer hydrogenation of oleic acid to octadecanol over magnetic recoverable cobalt catalysts
Wang, Juncheng,Nie, Renfeng,Xu, Ling,Lyu, Xilei,Lu, Xiuyang
supporting information, p. 314 - 320 (2019/01/28)
Efficient transformation of biomass into fuel and chemicals under mild conditions with cost-effective and environmentally friendly characters is highly desirable but still challenging. Herein, a scalable and Earth-abundant cobalt catalyst was used for selective catalytic transfer hydrogenation (CTH) of unsaturated fatty acids to fatty alcohols with sustainable isopropanol as a hydrogen donor. By tuning the surface Co composition by varying the reduction temperature, the catalytic performance could be easily boosted. At 200 °C in 4 h, the optimal catalyst Co-350 (reduced at 350 °C) gives 100% oleic acid conversion with 91.9% octadecanol selectivity. Various characterization studies reveal that the co-existence of Coδ+ and Co0 over the cobalt core might be responsible for its high performance for CTH of oleic acid. This catalyst could be magnetically separated and is highly stable for reusing ten times. Moreover, this cobalt catalyst is relatively cheap and easy to scale-up, thus achieving a low-cost transformation of biomass into high value-added chemicals.
In situ hydrogenation and decarboxylation of oleic acid into heptadecane over a Cu-Ni alloy catalyst using methanol as a hydrogen carrier
Zhang, Zihao,Yang, Qiwei,Chen, Hao,Chen, Kequan,Lu, Xiuyang,Ouyang, Pingkai,Fu, Jie,Chen, Jingguang G.
supporting information, p. 197 - 206 (2018/01/12)
In this work, supported Cu-Ni bimetallic catalysts were synthesized and evaluated for the in situ hydrogenation and decarboxylation of oleic acid using methanol as a hydrogen donor. The supported Cu-Ni alloy exhibited a significant improvement in both activity and selectivity towards the production of heptadecane in comparison with monometallic Cu and Ni based catalysts. The formation of the Cu-Ni alloy is demonstrated by high-angle annular dark-field scanning transmission electron microscopy (HADDF-STEM), energy dispersive X-ray spectroscopy (EDS-mapping), X-ray diffraction (XRD) and temperature programmed reduction (TPR). A partially oxidized Cu in the Cu-Ni alloy is revealed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) following CO adsorption and X-ray photoelectron spectroscopy (XPS). The temperature programmed desorption of ethylene and propane (ethylene/propane-TPD) suggested that the formation of the Cu-Ni alloy inhibited the cracking of C-C bonds compared to Ni, and remarkably increased the selectivity to heptadecane. The temperature programmed desorption of acetic acid (acetic acid-TPD) indicated that the bimetallic Cu-Ni alloy and Ni catalysts had a stronger adsorption of acetic acid than that of the Cu catalyst. The formation of the Cu-Ni alloy and a partially oxidized Cu facilitates the decarboxylation reaction and inhibits the cracking reaction of C-C bonds, leading to enhanced catalytic activity and selectivity.
