Topic
Carboxylic acid
About: Carboxylic acid is a research topic. Over the lifetime, 48544 publications have been published within this topic receiving 605696 citations.
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TL;DR: A marine fungal isolate, identified as Acremonium sp.
Abstract: A marine fungal isolate, identified as Acremonium sp., was mass cultivated and found to produce two novel hydroquinone derivatives, 7-isopropenylbicyclo[4.2.0]octa-1,3,5-triene-2,5-diol (1) and 7-isopropenylbicyclo[4.2.0]octa-1,3,5-triene-2,5-diol-5-beta-D-glucopyranoside (2). Compound 1 and its glucoside 2 possess a most unusual ring system. The new natural products (3R,4S)-3,4-dihydroxy-7-methyl-3,4-dihydro-1(2H)naphthalenone (3) and (3S,4S)-3,4-dihydroxy-7-methyl-3,4-dihydro-1(2H)-naphthalenone (4) were obtained as a 1:0.8 mixture. 2-(1-Methylethylidene)pentanedioic acid (5) was isolated for the first time as a natural product and its structure proven by X-ray analysis. In addition to these compounds an inseparable mixture of three new isomeric compounds, pentanedioic acid 2-(1-methylethylidene)-5-methyl ester (6), pentanedioic acid 2-(1-methylethylidene)-1-methyl ester (7), and pentanedioic acid 2-(1-methylethenyl)-5-methyl ester (8), was also obtained. Isolated together with the new compounds were three known hydroquinone derivatives, 9, 10, and 11. The structures of all compounds were determined by interpretation of their spectroscopic data (1D and 2D NMR, MS, UV, and IR). Each isolate was tested for its antioxidant properties, and compounds 1 and 9-11 were found to have significant activity.
93 citations
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TL;DR: An additive-free catalytic system for hydrogenation of carboxylic acid esters to alcohols with a well-defined cobalt pincer catalyst precursor was reported in this article.
Abstract: Here, we report an additive-free catalytic system for hydrogenation of carboxylic acid esters to alcohols with a well-defined cobalt pincer catalyst precursor. Various substrates, including methyl, ethyl, and benzyl esters, have been evaluated under hydrogenation conditions; however, methyl esters have low reactivity compared to those of the corresponding ethyl and benzyl esters. The biomass-derived γ-valerolactone successfully formed 1,4-pentanediol with a turnover number of 3890 with this system. Metal–ligand cooperativity is probed with the related [PN(Me)P] derivative of the cobalt catalyst, and the results suggest a nonbifunctional hydrogenation mechanism.
93 citations
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TL;DR: In this article, new N-methylimidazole-functionalized gold clusters catalyze, in 6∶4 methanol-water solution, the cleavage of 2,4-dinitrophenyl acetate with more than an order of magnitude speed up with respect to acetyl-N-methylhistamine.
93 citations
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TL;DR: In vivo MRI experiments on tumor-bearing mice demonstrated that the PEG-coated nanoparticles prepared by the current approach achieved an appreciable accumulation into solid tumor, suggesting their potential utility as tumor-selective MRI contrast agents.
93 citations
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TL;DR: The synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.
Abstract: Nicotinic acid (also known as vitamin B3) is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids). The tested copper complexes exhibited superoxide dismutase (SOD) mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 µg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph) was the most potent with a SOD mimetic activity of IC 50 34.42 µM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT) at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA) value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to
93 citations