- A metal-free strategy for the cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol
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Here, we report a metal-free approach for the construction of methylene-bridged bis-1,3-dicarbonyl compounds via cross-dehydrogenative coupling of 1,3-dicarbonyl compounds with 2-methoxyethanol. In addition, we have extended this methodology to synthesize tetra-substituted pyridine derivatives using 1,3-dicarbonyl, 2-methoxyethanol and NH4OAc in one step. The key advantages include accepting a wide range of substrates, utilizing O2 as the sole oxidant, and synthesizing biologically active compounds such as 1,4-dihydropyridine and pyrazole. This journal is
- Chang, Yu-Lun,Huang, Sheng-Hua,Kudale, Vishal Suresh,Wang, Jeh-Jeng,Zheng, Sheng
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supporting information
p. 1226 - 1230
(2022/02/21)
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- Rhodium-Catalyzed Aerobic Decomposition of 1,3-Diaryl-2-diazo-1,3-diketones: Mechanistic Investigation and Application to the Synthesis of Benzils
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The conversion of 1,3-diaryl-2-diazo-1,3-diketones to 1,2-daryl-1,2-diketones (benzils) is reported based on a rhodium(II)-catalyzed aerobic decomposition process. The reaction occurs at ambient temperatures and can be catalyzed by a few dirhodium carboxylates (5 mol %) under a balloon pressure of oxygen. Moreover, an oxygen atom from the O2 reagent is shown to be incorporated into the product, and this is accompanied by the extrusion of a carbonyl unit from the starting materials. Mechanistically, it is proposed that the decomposition may proceed via the interaction of a ketene intermediate resulting from a Wolff rearrangement of the carbenoid, with a rhodium peroxide or peroxy radical species generated upon the activation of molecular oxygen. The proposed mechanism has been supported by the results from a set of controlled experiments. By using this newly developed strategy, a large array of benzil derivatives as well as 9,10-phenanthrenequinone were synthesized from the corresponding diazo substrates in varying yields. On the other hand, the method did not allow the generation of benzocyclobutene-1,2-dione from 2-diazo-1,3-indandione because of the difficulty of inducing the initial rearrangement.
- Zhu, Jia-Liang,Tsai, Yi-Ting
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p. 813 - 828
(2020/12/22)
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- An effective preparation of both 1,3-diketones and nitriles from alkynones with oximes as hydroxide sources
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An effective phosphine-catalyzed protocol has been established for the syntheses of 1,3-diketones and nitriles from alkynones with oximes as hydroxide surrogates. This method features the use of a phosphine catalyst, compatibility with various functional groups and ambient temperature, which makes this approach very practical. A plausible mechanism was proposed.
- Chen, Pei,Zhang, Qian-Qian,Guo, Jia,Chen, Lu-Lu,Wang, Yan-Bo,Zhang, Xiao
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p. 6958 - 6966
(2018/10/02)
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- Novel rare earth europium complex and preparation method thereof
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The invention discloses a novel rare earth europium complex and a preparation method thereof. The method includes the following steps of firstly, conducting acylation reaction with acetophenone and benzenedicarboxylic acid dimethyl ester as the raw materi
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Paragraph 0045; 0086; 0087; 0088; 0089
(2016/10/10)
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- Transition-metal-free formal decarboxylative coupling of ?±-oxocarboxylates with ?±-bromoketones under neutral conditions: A simple access to 1,3-diketones
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A transition-metal-free formal decarboxylative coupling reaction between ?±-oxocarboxylates and ?±-bromoketones to synthesize 1,3-diketone derivatives is presented. In this reaction, a broad scope of substrates can be employed, and neither a metal-based reagent nor an additional base is required. DFT calculations reveal that this reaction proceeds through a coupling followed by decarboxylation mechanism and the ?±-bromoketone unprecedentedly serves as a nucleophile under neutral conditions. The rate-determining step is an unusual hydrogen-bond-assisted enolate formation by thermolysis.
- He, Zhen,Qi, Xiaotian,Li, Shiqing,Zhao, Yinsong,Gao, Ge,Lan, Yu,Wu, Yiwei,Lan, Jingbo,You, Jingsong
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p. 855 - 859
(2015/02/05)
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- Electronic and spectroscopic properties of avobenzone derivatives attached to Mo2 quadruple bonds: Suppression of the photochemical enol-to-keto transformation
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From the reactions between Mo2(TiPB)4, where TiPB is 2,4,6-triisopropylbenzoate, and 2 equiv of the acids 4-formylbenzoic acid, HBzald; 4-(3-oxo-3-phenylpropanoyl)benzoic acid, HAvo; and 4-(2,2-difluoro-6-phenyl
- Chisholm, Malcolm H.,Durr, Christopher B.,Gustafson, Terry L.,Kender, William T.,Spilker, Thomas F.,Young, Philip J.
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p. 5155 - 5162
(2015/05/05)
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- NOVEL COMPOUNDS
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This invention relates to compounds of formula (I) their use as positive allosteric modulators of mGlu5 receptor activity, pharmaceutical compositions containing the same, and methods of using the same as agents for treatment and/or prevention of neurological and psychiatric disorders associated with glutamate dysfunction such as schizophrenia or cognitive decline such as dementia or cognitive impairment. A, B, Ar, R1, R2, R3 have meanings given in the description.
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Page/Page column 54
(2013/06/27)
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- NOVEL COMPOUNDS
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This invention relates to compounds of formula I their use as positive allosteric modulators of mGlu5 receptor activity, pharmaceutical compositions containing the same, and methods of using the same as agents for treatment and/or prevention of neurological and psychiatric disorders associated with glutamate dysfunction such as schizophrenia or cognitive decline such as dementia or cognitive impairment. A, B, Ar, R1, R2, R3 have meanings given in the description.
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Paragraph 0261; 0262; 0263
(2013/06/05)
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- Dibenzoyldiazomethane-acridine conjugate: A novel DNA photofootprinting agent
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Dibenzoyldiazomethane derivative covalently attached to acridine effectively cleaves DNA by photoirradiation with long wavelength W light (> 400 nm). DNA cleavage experiments using 32P-5'-end-labeled DNA showed that the cleavage by the conjugate is neither sequence nor base selective, indicating that DBDM-acridine conjugate can be used as a photofootprinting agent.
- Nakatani, Kazuhiko,Shirai, Junya,Sando, Shinsuke,Saito, Isao
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p. 6047 - 6050
(2007/10/03)
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- Guanine specific DNA cleavage by photoirradiation of dibenzoyldiazomethane - Oligonucleotide conjugates
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Photoirradiation of dibenzoyldiazomethane (DBDM) produced highly electrophilic benzoylketene via Wolff rearrangement. DBDM derivative possessing an aminoalkyl side chain induced a DNA cleavage selectively at guanine (G) residues upon photoirradiation and subsequent piperidine treatment. In order to devise photochemical DNA cleavers that can specifically alkylate a guanine residue proximal to the target sequence of long DNA fragments, a sew reagent, DBDM-OSu, which facilitates the connection of DBDM unit to various DNA binders, was developed. DBDM-oligonucleotide (ODN) conjugates 5 and 6 were obtained by the coupling of 5'-aminohexyl 8-mer [H2N-CH2)6-d(ACGTCAGG)-3'] and 15-mer [H2N-(CH2)6-d(ACGTCAGGTGGCACT)-3'], respectively, with DBDM-OSu in aqueous acetonitrile in the presence of sodium bicarbonate. Photoirradiation of 5 and 6 in the presence of 25-mer 5'-d(AGTGCCACCTGACGTCTG18CTCTCTC)-3' having a complementary sequence induced cross-linking of both oligomers. A distinct cleavage band at guanine residue (G18) was observed upon heating the cross-linked oligomers with piperidine. A similar DNA cleavage reaction of 5'-d(AGTGCCACCTGACG14TG16CG18TG20CG22-TCT)-3' having multiple guanine sites in the presence of DBDM-ODN conjugate 6 indicated that the most effectively cleaved site is G16. These results demonstrated that DBDM-oligonucleotide conjugates can serve as a new class of photonucleases that can cleave single-stranded DNA at predetermined guanine sites. Furthermore, the reagent DBDM-OSu can be used as a convenient and effective photoinducible electrophile for the cross-linking or the modification of biopolymers.
- Nakatani, Kazuhiko,Shirai, Junya,Sando, Shinsuke,Saito, Isao
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p. 7626 - 7635
(2007/10/03)
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