- Boryl Radical Activation of Benzylic C-OH Bond: Cross-Electrophile Coupling of Free Alcohols and CO2via Photoredox Catalysis
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A new strategy for the direct cleavage of the C(sp3)-OH bond has been developed via activation of free alcohols with neutral diphenyl boryl radical generated from sodium tetraphenylborate under mild visible light photoredox conditions. This strategy has been verified by cross-electrophile coupling of free alcohols and carbon dioxide for the synthesis of carboxylic acids. Direct transformation of a range of primary, secondary, and tertiary benzyl alcohols to acids has been achieved. Control experiments and computational studies indicate that activation of alcohols with neutral boryl radical undergoes homolysis of the C(sp3)-OH bond, generating alkyl radicals. After reducing the alkyl radical into carbon anion under photoredox conditions, the following carboxylation with CO2 affords the coupling product.
- Jiang, Yi-Qian,Lan, Yu,Li, Shi-Jun,Li, Wen-Duo,Li, Yan-Lin,Wu, Yang,Xia, Ji-Bao
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- Abiotic degradation and environmental toxicity of ibuprofen: Roles of mineral particles and solar radiation
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The growing medical and personal needs of human populations have escalated release of pharmaceuticals and personal care products into our natural environment. This work investigates abiotic degradation pathways of a particular PPCP, ibuprofen, in the presence of a major mineral component of soil (kaolinite clay), as well as the health effects of the primary compound and its degradation products. Results from these studies showed that the rate and extent of ibuprofen degradation is greatly influenced by the presence of clay particles and solar radiation. In the absence of solar radiation, the dominant reaction mechanism was observed to be the adsorption of ibuprofen onto clay surface where surface silanol groups play a key role. In contrast, under solar radiation and in the presence of clay particles, ibuprofen breaks down to several fractions. The decay rates were at least 6-fold higher for irradiated samples compared to those of dark conditions. Toxicity of primary ibuprofen and its secondary residues were tested on three microorganisms: Bacillus megaterium, Pseudoaltermonas atlantica; and algae from the Chlorella genus. The results from the biological assays show that primary PPCP is more toxic than the mixture of secondary products. Overall, however, biological assays carried out using only 4-acetylbenzoic acid, the most abundant secondary product, show a higher toxic effect on algae compared to its parent compound.
- Rubasinghege, Gayan,Gurung, Rubi,Rijal, Hom,Maldonado-Torres, Sabino,Chan, Andrew,Acharya, Shishir,Rogelj, Snezna,Piyasena, Menake
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- Preparation method of loxoprofen sodium ring opened impurity
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The invention relates to a preparation method of a loxoprofen sodium ring opened impurity, and belongs to the technical field of bulk drug preparation. The preparation method comprises the following steps: step one, carrying out substitution reactions between a compound represented by a formula I and hexamethylene tetramine in an organic solvent A, hydrolyzing the reaction product by inorganic acids to obtain a compound represented by a formula II; carrying out condensation reactions between the compound represented by the formula II and a compound represented by a formula III in an organic solvent B to obtain a compound represented by a formula IV; carrying out oxidation and ring opening reactions of the compound represented by the formula IV under the effect of an oxidant and inorganic alkalis to obtain the loxoprofen sodium ring opened impurity represented by a formula V. The invention provides a preparation method of the loxoprofen sodium ring opened impurity.
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Paragraph 0012; 0016; 0018; 0020; 0022; 0024; 0026
(2017/12/09)
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- Site-Selective Catalytic Carboxylation of Unsaturated Hydrocarbons with CO2 and Water
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A catalytic protocol that reliably predicts and controls the site-selective incorporation of CO2 to a wide range of unsaturated hydrocarbons utilizing water as formal hydride source is described. This platform unlocks an opportunity to catalytically repurpose three abundant, orthogonal feedstocks under mild conditions.
- Gaydou, Morgane,Moragas, Toni,Juliá-Hernández, Francisco,Martin, Ruben
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supporting information
p. 12161 - 12164
(2017/09/12)
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- Regiocontrolled Photooxygenation of Ibuprofen by Pyrimidopteridinetetrone- and Anthraquinone-Oxygen Systems
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Ibuprofen 4 underwent regiocontrolled photooxygenation on the propionic acid and isobutyl moieties in the presence of pyrimidopteridinetetrone 1- and anthraquinone 3- oxygen systems.
- Sako, Magoichi,Oyabu, Iwao,Hirota, Kosaku,Maki, Yoshifumi
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p. 601 - 602
(2007/10/02)
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- Novel phenylacetic acid derivatives
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Phenylacetic acid derivatives of the formula STR1 wherein n is an integer of 2 to 5; STR2 R1 is hydrogen, halogen, trifluoromethyl, nitro or amino; R2 and R3 each independently is hydrogen or lower alkyl; or together form an ethylene group; X1 represents two hydrogen atoms or an oxo group; and Y1 is cyano, hydroxyamidocarbonyl, carbamoyl, 5-tetrazolyl or carboxyl; and for derivatives wherein Y is carboxyl, salts thereof with physiologically compatible bases, esters thereof from physiologically acceptable alcohols and amides thereof from physiologically acceptable amines have valuable pharmacological activity, e.g., as antiinflammatory agents.
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