- Regenerative role of the red phosphorus in the couple 'HIaq/Pred'
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The synthesis of ortho-substituted benzoic acid 3 from benzalphthalide 1 in the presence of 'hydriodic acid-red phosphorus' (HIaq/Pred) occurs via the formation of benzylphthalide 2 as reaction intermediate. Its preparation is optimized by use of the 'supported reaction in dry media' process (Silica/HIaq) under microwave irradiation for 8 min. The role of the red phosphorus in the reduction reaction is elucidated: it intervenes in a catalytic cycle by an oxido-reductive disproportionation with the liberated iodine, affording either hypophosphorous acid in aqueous media, or P2I4 in anhydrous media with concomitant regeneration of HI. Thus, the presence of Pred in the couple 'HIaq/Pred' allows recycling of the hydriodic acid and enhances its reducing efficiency.
- Albouy, Dominique,Etemad-Moghadam, Guita,Vinatoru, Mircea,Koenig, Max
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Read Online
- Enantioselective Remote C(sp3)-H Cyanation via Dual Photoredox and Copper Catalysis
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The remote C(sp3)-H cyanation of carboxamides has been described by merging photoredox and copper catalysis in a site-selective and enantiocontrolled manner. The protocol is the integration of photoinduced and nitrogen-centered radical-mediated intermolecular hydrogen atom transfer with chiral copper-complex-catalyzed radical cyanation. This strategy gives enantio-enriched cyanated amides in high yields.
- Chen, Hui,Jin, Weiwei,Yu, Shouyun
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p. 5910 - 5914
(2020/08/12)
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- Cooperative iodine and photoredox catalysis for direct oxidative lactonization of carboxylic acids
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A new method for the formation of γ- and δ-lactones from carboxylic acids through direct conversion of benzylic C-H to C-O bonds is described. The reaction is conveniently induced by visible light and relies on a mild cooperative catalysis by the combination of molecular iodine and an organic dye.
- Duhamel, Thomas,Mu?iz, Kilian
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p. 933 - 936
(2019/01/23)
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- Synthesis method of psychotropic drug-amitriptyline intermediate compound
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The invention relates to a synthesis method of a psychotropic drug-amitriptyline intermediate compound, i.e., a compound 2-(2-phenylethyl)benzoic acid shown in a formula (III), and the formula (III) is described in the description. The synthesis method concretely comprises the following steps: enabling a compound shown in a formula (I) to react with a compound shown in a formula (II) in a bicomponent organic solvent at the temperature of 70-100 DEG C in presence of a catalyst, a nitrogen polydentate ligand, an oxidant and organic alkali, and carrying out aftertreatment after the reaction is finished so as to obtain the compound shown in the formula (III), wherein the formula (I) and the formula (II) are described in the description, X is halogen, Y is alkali-metal element, and R is H or analkyl group having 1-6 carbon atoms. After the method is adopted, a high yield and high purity target product can be obtained by means of a specific comprehensive reaction system, so that a novel route is provided for the synthesis of the amitriptyline intermediate; the synthesis method has good research value and industrialization amplification potential.
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Paragraph 0069-0072; 0076; 0077; 0082; 0087
(2018/07/30)
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- Preparation method of carboxylic acid compound
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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.
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Paragraph 0113; 0211-0213
(2017/08/29)
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- A Comprehensive Study on Metal Triflate-Promoted Hydrogenolysis of Lactones to Carboxylic Acids: From Synthetic and Mechanistic Perspectives
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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.
- Zhu, Rui,Jiang, Ju-Long,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 7520 - 7528
(2017/11/10)
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- Electrophilic aromatic substitution of arenes with CO2 mediated by R3SiB(C6F5)4
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The FriedelCrafts- type carboxylation of arenes has been achieved by activating CO2 with silylium borates. The reaction exhibits broader substrate applicability than does our previously reported AlX3/R 3SiX-mediated carboxylation.
- Konno, Megumi,Chiba, Masafumi,Nemoto, Koji,Hattori, Tetsutaro
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p. 913 - 914,2
(2020/08/31)
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- Raney nickel-catalyzed hydrogenation of unsaturated carboxylic acids with sodium borohydride in water
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A mild, selective, and green method for the reduction of unsaturated carboxylic acids with sodium borohydride-Raney nickel (W6) system in water is reported. This method is practical and safe and avoids use of organic solvents. Taylor & Francis Group, LLC.
- Rao, Gopal Krishna,Gowda, Narendra B.,Ramakrishna, Ramesha A.
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experimental part
p. 893 - 904
(2012/02/01)
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- Iron(III) chloride-catalysed aerobic reduction of olefins using aqueous hydrazine at ambient temperature
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A chemoselective reduction of olefins and acetylenes is demonstrated by employing catalytic amounts of ferric chloride hexahydrate (FeCl 3·6 H2O) and aqueous hydrazine (NH 2NH2·H2O) as hydrogen source at room temperature. The reduction is chemoselective and tolerates a variety of reducible functional groups. Unlike other metal-catalysed reduction methods, the present method employs a minimum amount of aqueous hydrazine (1.5-2 equiv.). Also, the scope of this method is demonstrated in the synthesis of ibuprofen in aqueous medium. Copyright
- Lamani, Manjunath,Ravikumara, Guralamata S.,Prabhu, Kandikere Ramaiah
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supporting information; experimental part
p. 1437 - 1442
(2012/07/03)
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- Guanidine catalyzed aerobic reduction: A selective aerobic hydrogenation of olefins using aqueous hydrazine
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An efficient aerobic reduction of olefins, internal as well as terminal, is developed using guanidine as an organocatalyst. A remarkable chemoselectivity in reduction has been demonstrated in the presence of a variety of functional groups and protective groups and a selective reduction of a terminal olefin in the presence of an internal olefin is revealed.
- Lamani, Manjunath,Guralamata, Ravikumara Siddappa,Prabhu, Kandikere Ramaiah
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supporting information; experimental part
p. 6583 - 6585
(2012/07/14)
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- NOVEL COMPOUNDS, THEIR PREPARATION AND USE
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Novel compounds of the general formula (I), the use of these compounds as phar- maceutical compositions, pharmaceutical compositions comprising the compounds and methods of treatment employing these compounds and compositions. The present compounds may be useful in the treatment and/or prevention of conditions mediated by Peroxisome Proliferator-Activated Receptors (PPAR), in particular the PPARδ suptype.
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Page/Page column 29-30
(2010/02/14)
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- Branched chain amino acid-dependent aminotransferase inhibitors and their use in the treatment of neurodegenerative diseases
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The invention relates to BCAT inhibitors and the use thereof for treating or preventing neuronal loss associated with stroke, ischemia, CNS trauma, hypoglycemia and surgery, as well as treating neurodegenerative diseases including Alzheimer's disease, amyotrophic lateral sclerosis, Huntington's disease and Down's syndrome, treating or preventing the adverse consequences of the overstimulation of the excitatory amino acids, treating anxiety, psychosis, convulsions, aminoglycoside antibiotics-induced hearing loss, migraine headache, chronic pain, neuropathic pain, Parkinson's disease, diabetic retinopathy, glaucoma, CMV retinitis, urinary incontinence, opioid tolerance or withdrawal, and inducing anesthesia, as well as for enhancing cognition.
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- Convenient synthesis of 2-(2-phenylethyl)benzoic acid: A key intermediate in the synthesis of dibenzosuberone
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A convenient and improved synthesis of 2-(2-phenylethyl) benzoicacid, a key intermediate in the synthesis of dibenzosuberone is described.
- Ramesha,Roy
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p. 2419 - 2422
(2007/10/03)
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- 4-Aminoquinolines: Novel nociceptin antagonists with analgesic activity
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Small-molecule nociceptin antagonists were synthesized to examine their therapeutic potential. After a 4-aminoquinoline derivative was found to bind with the human ORL1 receptor, a series of 4-aminoquinolines and related compounds were synthesized and their binding was evaluated. Elucidation of structure - Activity relationships eventually led to the optimum compounds. One of these compounds, N-(4-amino-2-methylquinolin-6-yl)-2-(4-ethylphenoxymethyl)benzamide hydrochloride (11) not only antagonized nociceptin-induced allodynia in mice but also showed analgesic effect in a hot plate test using mice and in a formalin test using rats. Its analgesic effect was not antagonized by the opioid antagonist naloxone. These results indicate that this nociceptin antagonist has the potential to become a novel type of analgesic that differs from μ-opioid agonists.
- Shinkai,Ito,Iida,Kitao,Yamada,Uchida
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p. 4667 - 4677
(2007/10/03)
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- Reductive cleavage of phthalides with iodotrimethylsilane
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A convenient reductive cleavage of 3-arylphthalides 1 into corresponding 2-benzylbenzoic acids and 2-(2-thienylmethyl)benzoic acid 2 by using iodotrimethylsilane is described.
- Sabitha, Gowravaram,Yadav
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p. 3065 - 3071
(2007/10/03)
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- Novel applications of Raney nickel/isopropanol: Efficient system for the reduction of organic compounds
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Catalytic hydrogenation of various organic substrates with Raney nickle in isopropanol proceeds under mild conditions of temperature and pressure. Comparison with other catalysts systems evidenced the superiority of Raney nickel/isopropanol.
- Regla, Ignacio,Reyes, Adelfo,Koerber, Claudia,Demare, Patricia,Estrada, Osvaldo,Juaristi, Eusebio
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p. 817 - 823
(2007/10/03)
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- Asymmetric syntheses of 1,6-dialkyl-1,4-cyclohexadiene derivatives
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Ortho-lithiation-alkylation of tertiary benzamide 3 provides a series of 2-substituted chiral benzatnides 3a-g (Scheme I). Birch reduction of 3a-j followed by alkylation of the resulting chiral amide enolate with Mel at -78 °C gives 1,6-di-alkyl-1,4-cyclohexadiene derivatives 4a-j with excellent diastereoselectivities (Table I). Applications of this asymmetric synthesis are illustrated by conversions of 4g to enantiomerically pure bicyclic lactone 9 and octalone 11 (Scheme III) and 4j to hexahydro-9-anthracenone 14 (Scheme IV).
- Schultz, Arthur G.,Green, Neal J.
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p. 4931 - 4936
(2007/10/02)
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- The Effects of Stereochemistry of the Bridging Atoms in o-Substituted Arylbenzoic Acids on Root Antigravitropism
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Compounds in which an aryl or heteroaryl ring is linked to the ortho position of a benzoic acid moiety by a bridging group of up to four atoms are shown to inhibit the gravitropic response of cress seedling roots between 1E-5 and 1E-8 M.No significant difference in inhibitory activity is observed between compounds containing up to four saturated or two partially unsaturated bridging atoms, although analogues containing three or four partially unsaturated bridging atoms are one to two orders of magnitude more active.Compounds in which the aryl nuclei are fused together are shown to be inactive at the highest concentration tested.The results have been interpreted in terms of the aryl groups in the molecule interacting with a hypothetical receptor site, with the bridging atoms acting as a more or less flexible coupling to facilitate such interaction.
- Teitei, Tsutomu
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p. 1461 - 1466
(2007/10/02)
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