- Electrochemical oxidation-induced benzyl C–H carbonylation for the synthesis of aromatic α-diketones
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Electrochemical oxidation-induced direct carbonylation of benzyl C–H bond for the synthesis of aromatic α-diketones is described. In this process, tetrabutylammonium iodide (nBu4NI) not only acts as an electrolyte, but its iodine anion is oxidized to an iodine radical at the anode, acting as a hydrogen atom transfer agent. The iodine radical extracts the benzyl hydrogen atom and causes the carbonylation of the benzyl position, where O2 in the air is used as an oxygen source.
- Tan, Yu-Fang,Chen, Yuan,Li, Rui-Xue,Guan, Zhi,He, Yan-Hong
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supporting information
(2021/12/21)
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- Preparation method of aryl ketone compound
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The invention provides a preparation method of an aryl ketone compound, and belongs to the technical field of compound synthesis. The method comprises the following steps: under the action of a silver catalyst and water, carrying out reaction on aryl alkyne with a structure as shown in a formula 1 in a solvent at 60-120 DEG C for 12-48 hours, and separating and purifying a product after the reaction is finished, so as to obtain the single aryl ketone compound with a structure as shown in a formula I, the raw materials are easy to obtain, the experimental operation is simple, the yield of the prepared single aryl ketone compound is good, and gram-scale experiments can be carried out.
- -
-
Paragraph 0041-0049; 0061-0066
(2022/04/16)
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- Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
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Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
- Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
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supporting information
p. 8910 - 8917
(2020/12/23)
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- Thianthrenation-enabled α-arylation of carbonyl compounds with arenes
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The Pd-catalyzed α-arylation of carbonyl compounds with simple arenes enabled by site-selective thianthrenation has been demonstrated. This onepot process using thianthrenium salts as the traceless arylating reagents features mild conditions and a broad substrate scope. In addition, this protocol could also tolerate the heterocyclic carbonyl compounds and complex bioactive molecules, which is appealing for medicinal chemistry.
- Huang, Yu-Hao,Nie, Xiao-Xue,Wang, Peng
-
supporting information
p. 7716 - 7720
(2020/11/02)
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- Diazaphosphinyl radical-catalyzed deoxygenation of α-carboxy ketones: A new protocol for chemo-selective C-O bond scission: Via mechanism regulation
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C-O bond cleavage is often a key process in defunctionalization of organic compounds as well as in degradation of natural polymers. However, it seldom occurs regioselectively for different types of C-O bonds under metal-free mild conditions. Here we report a facile chemo-selective cleavage of the α-C-O bonds in α-carboxy ketones by commercially available pinacolborane under the catalysis of diazaphosphinane based on a mechanism switch strategy. This new reaction features high efficiency, low cost and good group-tolerance, and is also amenable to catalytic deprotection of desyl-protected carboxylic acids and amino acids. Mechanistic studies indicated an electron-transfer-initiated radical process, underlining two crucial steps: (1) the initiator azodiisobutyronitrile switches originally hydridic reduction to kinetically more accessible electron reduction; and (2) the catalytic phosphorus species upconverts weakly reducing pinacolborane into strongly reducing diazaphosphinane. This journal is
- Cheng, Jin-Pei,Yang, Jin-Dong,Zhang, Jingjing
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p. 8476 - 8481
(2020/09/07)
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- 2,2-Diazido-1,2-diarylethanones: Synthesis and Reactivity with Primary Amines
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We describe the synthesis and reactivity of a new class of diazidated compounds: the 2,2-diazido-1,2-diarylethanones. The diazides are easily accessible from 1,2-diarylethanones through a mild and simple protocol for the direct oxidative diazidation, using iodine and sodium azide in DMSO at room temperature. In studies towards their reactivity with amine nucleophiles under basic conditions, the diazides are shown to undergo a controlled fragmentation reaction that provides a straightforward access to the corresponding amides. In stark contrast to our previous results on the amine-triggered fragmentation of diazidated compounds, aromatic nitriles are found to be by-products of synthetic value. The net reaction consisting of diazidation and subsequent fragmentation, thus, provides a simple way to convert 1,2-diarylethanones into both aromatic amides and nitriles.
- Holzschneider, Kristina,H?ring, Andreas P.,Kirsch, Stefan F.
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p. 2824 - 2831
(2019/04/30)
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- Silica-supported orthophosphoric acid (OPA/SiO2): preparation, characterization, and evaluation as green reusable catalyst for pinacolic rearrangement
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In this paper, we report an easy-to-prepare, cost-effective, efficient, and reusable silica-supported orthophosphoric acid (OPA) catalyst for pinacolic rearrangement. The surface properties of this catalyst were successfully characterized with the help of 31P NMR, TGA, DSC, FT-IR, titration, and microscopy. OPA, hydrogen bonded on the surface, is actually the active species and the reaction seems to occur in the liquid phase embedded in the silica support. As a consequence, the extracting solvent should be chosen with cautious to guarantee the recyclability of the catalyst. As example, pinacol rearrangement reactions were successfully realized with this catalyst and OPA/SiO2 proved to be as efficient as homogeneous orthophosphoric acid to promote the reaction of pinacol derivatives. When using dichloromethane as extracting solvent, OPA/SiO2 can be reuse up to ten times without a significant loss of activity. After ten runs, no physical damage of the catalyst has been observed by microscopy proving its suitability for such application.
- Billamboz, Muriel,Banaszak, Estelle
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p. 1029 - 1040
(2019/04/10)
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- Novel sulfenamides and sulfonamides based on pyridazinone and pyridazine scaffolds as CB1 receptor ligand antagonists
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A series of sulfenamide and sulfonamide derivatives was synthesized and evaluated for the affinity at CB1 and CB2 receptors. The N-bornyl-S-(5,6-di-p-tolylpyridazin-3-yl)-sulfenamide, compound 11, displayed good affinity and high selectivity for CB1 receptors (Ki values of 44.6 nM for CB1 receptors and >40 μM for CB2 receptors, respectively). The N-isopinocampheyl-sulfenamide 12 and its sulfonamide analogue 22 showed similar selectivity for CB1 receptors with Ki values of 75.5 and 73.2 nM, respectively. These novel compounds behave as antagonists/inverse agonists at CB1 receptor in the [35S]-GTPγS binding assays, and none showed adequate predictive blood–brain barrier permeation, exhibiting low estimated LD50. However, testing compound 12 in a supraspinal analgesic test (hot-plate) revealed that it was as effective as the classic CB1 receptor antagonist rimonabant, in reversing the analgesic effect of a cannabinoid agonist.
- Murineddu, Gabriele,Deligia, Francesco,Ragusa, Giulio,García-Toscano, Laura,Gómez-Ca?as, María,Asproni, Battistina,Satta, Valentina,Cichero, Elena,Pazos, Ruth,Fossa, Paola,Loriga, Giovanni,Fernández-Ruiz, Javier,Pinna, Gerard A.
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p. 295 - 307
(2017/12/26)
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- Method for preparing diphenylethanone from benzyl alcohol through photocatalytic one-step method
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The present invention relates to a method for preparing diphenylethanone from benzyl alcohol through a photocatalytic one-step method. According to the method, diphenylethanone is directly prepared byusing inexpensive benzyl alcohol as a raw material under the action of a solid photocatalyst; and the reaction process comprises: mixing benzyl alcohol, a catalyst and an acetonitrile solvent are mixed, placing in a pressure container, replacing with an inert gas, and carrying out illumination stirring at a room temperature, wherein the reaction time is more than 1 h, the catalyst is easily separated from the reaction system after the reaction and can be recycled multiple times, and the separation yield of diphenylethanone is up to 81%.
- -
-
Paragraph 0037; 0038
(2018/09/13)
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- Two-Step One-Pot Synthesis of Unsymmetrical (Hetero)Aryl 1,2-Diketones by Addition-Oxygenation of Potassium Aryltrifluoroborates to (Hetero)Arylacetonitriles
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An efficient one-pot two-step procedure for the synthesis of unsymmetrical (hetero)aryl 1,2-diketones has been developed. The reaction proceeds through a palladium-catalyzed nucleophilic addition of potassium aryltrifluoroborates to aliphatic nitriles followed by a copper-catalyzed aerobic benzylic C–H oxygenation using molecular oxygen as a green oxidant. This represents the first example of the direct synthesis of unsymmetrical diaryl 1,2-diketones from arylacetonitriles. This method utilizes inexpensive, stable, nontoxic, and readily available starting materials, is highly effective in the presence of both electron-rich and electron-poor nitriles and aryltrifluoroborates, and tolerates a wide variety of functional groups. The synthetic utility of this transformation was shown by increasing the scale of the reaction and by carrying out the one-pot protocol for the preparation of quinoxaline and benzimidazole derivatives. A plausible reaction mechanism has also been proposed.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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p. 494 - 505
(2018/02/09)
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- Palladium-Catalyzed Chemo- and Enantioselective C?O Bond Cleavage of α-Acyloxy Ketones by Hydrogenolysis
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A chemoselective C?O bond cleavage of the ester alkyl side-chain of α-acyloxy ketones was realized for the first time by a highly efficient palladium-catalyzed hydrogenolysis (S/C=6000, the highest catalytic efficiency by far). Furthermore, a kinetic resolution of α-acyloxy ketones was first developed by enantioselective hydrogenolysis with good yields and up to 99 % ee.
- Chen, Jianzhong,Zhang, Zhenfeng,Liu, Delong,Zhang, Wanbin
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p. 8444 - 8447
(2016/07/19)
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- Copper-catalyzed base-accelerated direct oxidation of C-H bond to synthesize benzils, isatins, and quinoxalines with molecular oxygen as terminal oxidant
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We describe herein an efficient and general copper (II)-catalyzed base-accelerated oxidation of the C-H bond to synthesize benzils and isatins. With similar oxidation system an efficient one-pot procedure for the synthesis of quinoxaline derivatives was realized. The two protocols feature using molecular oxygen as terminal oxidant, low catalyst loading, wide substrate scope, and high functional-group tolerance.
- Yu, Jing-Wen,Mao, Shuai,Wang, Yong-Qiang
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p. 1575 - 1580
(2015/03/14)
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- Visible Light Mediated Reductive Cleavage of C-O Bonds Accessing α-Substituted Aryl Ketones
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C-O σ-bonds in multifaceted benzoin derivatives can be effectively cleaved as acetates using catalytic amounts of [Ru(bpy)3]Cl2 as photoredox catalyst in combination with Hantzsch ester and triethylamine as a sacrificial electron donor. This mild and operationally simple method is applicable to a great variety of substrates. Homo- and cross-benzoins, which are easily accessed by NHC (N-heterocyclic carbene) catalysis, with both electron-withdrawing and electron-donating substituents, including aryl halogenides, can be employed. The deoxygenated counterparts are isolated in good to excellent yields. These broadly accessible, α-substituted (nonsymmetric) aryl ketones are versatilely applicable for further transformations as illustrated by the syntheses of 2-arylbenzofurans.
- Speckmeier, Elisabeth,Padié, Clément,Zeitler, Kirsten
-
supporting information
p. 4818 - 4821
(2015/10/12)
-
- Structure-based design and synthesis of antiparasitic pyrrolopyrimidines targeting pteridine reductase 1
-
The treatment of Human African trypanosomiasis remains a major unmet health need in sub-Saharan Africa. Approaches involving new molecular targets are important; pteridine reductase 1 (PTR1), an enzyme that reduces dihydrobiopterin in Trypanosoma spp., has been identified as a candidate target, and it has been shown previously that substituted pyrrolo[2,3-d]pyrimidines are inhibitors of PTR1 from Trypanosoma brucei (J. Med. Chem. 2010, 53, 221-229). In this study, 61 new pyrrolo[2,3-d]pyrimidines have been prepared, designed with input from new crystal structures of 23 of these compounds complexed with PTR1, and evaluated in screens for enzyme inhibitory activity against PTR1 and in vitro antitrypanosomal activity. Eight compounds were sufficiently active in both screens to take forward to in vivo evaluation. Thus, although evidence for trypanocidal activity in a stage I disease model in mice was obtained, the compounds were too toxic to mice for further development.
- Khalaf, Abedawn I.,Huggan, Judith K.,Suckling, Colin J.,Gibson, Colin L.,Stewart, Kirsten,Giordani, Federica,Barrett, Michael P.,Wong, Pui Ee,Barrack, Keri L.,Hunter, William N.
-
supporting information
p. 6479 - 6494
(2014/10/16)
-
- Selective reduction of carbonyl groups in the presence of low-valent titanium reagents
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The chemoselective reduction of several structurally diverse compounds containing carbonyl groups was achieved in the presence of low-valent titanium reagents. This novel synthetic method provides easy access to highly selective reduction of carbonyl groups, and possesses several advantages including one-step procedure, convenient manipulation, good to excellent yields, and short reaction times.
- Lin, Wei,Hu, Ming-Hua,Feng, Xian,Fu, Lei,Cao, Cheng-Pao,Huang, Zhi-Bin,Shi, Da-Qing
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p. 2238 - 2242
(2014/04/17)
-
- A structureeactivity relationship study on the Wacker oxidation of stilbenes at ambient condition
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To evaluate which structural elements of the stilbenes are responsible for their activity on the Wacker oxidation, a series of stilbenes with various functional moieties and substitution patterns were considered. In this regard, it is found that the oxidation rate of stilbenes strongly depends on their structures to give the corresponding carbonyl compounds. Consequently, the ortho position of alkene and methoxy groups plays a key role in the complexation with PdCl2. The oxidation process is clean with high selectivity of product and low percentage of byproducts.
- Darabi, Hossein Reza,Mirzakhani, Mohsen,Aghapoor, Kioumars,Jadidi, Khosrow,Faraji, Laleh,Sakhaee, Nader
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p. 131 - 134
(2013/10/01)
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- Palladium-catalyzed mono-α-arylation of carbonyl-containing compounds with aryl halides using dalphos ligands
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We report the extension and optimization of the [Pd(cinnamyl)Cl] 2/DalPhos catalyst system, previously found effective for the mono-α-arylation of acetone, to the mono-α-arylation of a variety of carbonyl-containing compounds with aryl halides and heteroaryl halides. Aryl methyl ketones, heteroaryl methyl ketones, propiophenones, malonates, and methoxyacetone can be α-arylated under relatively mild conditions and in good yields. We also report the limitations of the ligand/catalyst system towards other classes of carbonyl-containing compounds. We report the application of the [Pd(cinnamyl)Cl]2/DalPhos catalyst system, previously found effective for the mono-α-arylation of acetone, to the mono-α-arylation of a variety of carbonyl-containing compounds with aryl halides and heteroaryl halides.
- Crawford, Sarah M.,Alsabeh, Pamela G.,Stradiotto, Mark
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p. 6042 - 6050,9
(2020/09/02)
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- Palladium-catalyzed mono-α-arylation of acetone with aryl imidazolylsulfonates
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Set the ace(tone): A palladium catalyst derived from the bidentate XantPhos ligand and Pd(OAc)2 has enabled broadly applicable mono-α-arylations of acetone to be performed with air- and moisture-stable aryl imidazolylsulfonates as most user-friendly electrophiles (see scheme). Copyright
- Ackermann, Lutz,Mehta, Vaibhav P.
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supporting information; experimental part
p. 10230 - 10233
(2012/09/22)
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- Photochemically initiated oxidative carbon-carbon bond-cleavage reactivity in chlorodiketonate NiII complexes
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Three mononuclear NiII complexes containing a 2-chloro-1,3-diketonate ligand and supported by the 6-Ph2TPA chelate, as well as analogues that lack the 2-chloro substituent on the β-diketonate ligand, have been prepared and characterized. Upon irradiation at 350 nm under aerobic conditions, complexes containing the 2-chloro-substituted ligands undergo reactions to generate products resulting from oxidative cleavage, α-cleavage, and radical-derived reactions involving the 2-chloro-1,3-diketonate ligand. Mechanistic studies suggest that the oxidative cleavage reactivity, which leads to the production of carboxylic acids, is a result of the formation of superoxide, which occurs through reaction of reduced nickel complexes with O2. The presence of the 2-chloro substituent was found to be a prerequisite for oxidative carbon-carbon bond-cleavage reactivity, as complexes lacking this functional group did not undergo these reactions following prolonged irradiation. The approach toward investigating the oxidative reactivity of metal β-diketonate species outlined herein has yielded results of relevance to the proposed mechanistic pathways of metalloenzyme-catalyzed β-diketonate oxidative cleavage reactions.
- Allpress, Caleb J.,Arif, Atta M.,Houghton, Dylan T.,Berreau, Lisa M.
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supporting information; body text
p. 14962 - 14973
(2012/02/06)
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- Direct synthesis of aryl ketones by palladium-catalyzed desulfinative addition of sodium sulfinates to nitriles
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Mild yet direct: A convenient and efficient method for the synthesis of various aryl ketones by palladium-catalyzed desulfinative addition of aromatic sulfinic acid sodium salts to various nitriles is described (see scheme). Aromatic and aliphatic nitriles are successfully reacted with arenesulfinic acid sodium salts to form aryl ketones in good yields.
- Liu, Jing,Zhou, Xianya,Rao, Honghua,Xiao, Fuhong,Li, Chao-Jun,Deng, Guo-Jun
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supporting information; experimental part
p. 7996 - 7999
(2011/08/22)
-
- Pd-catalyzed synthesis of α-aryl ketones through couplings of α-arylacetyl chlorides with triarylbismuths as multi-coupling nucleophiles
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The cross-coupling reaction of α-arylacetyl chlorides with triarylbismuths was studied under Pd-catalyzed conditions. The reaction was found to be facile under the established protocol and furnished high yields of α-aryl ketones in short reaction times. T
- Rao, Maddali L.N.,Giri, Somnath,Jadhav, Deepak N.
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experimental part
p. 6133 - 6138
(2010/02/27)
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- Synthesis, antileukemic and antiplatelet activities of 2,3-diaryl-6,7-dihydro-5H-1,4-diazepines
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The synthesis, antileukemic and antiplatelet activity evaluation of 2,3-diaryl-6,7-dihydro-5H-1,4-diazepines are described. In general, it was found that compound 17o showed moderate antileukemic activity against MOLT3 human leukemic cancer cell lines. An arachidonic acid induced platelet aggregation effect on washed rat platelets was studied. Compound 17i was found to be the most potent. The antiplatelet properties may be mediated by interference with the arachidonic acid pathway.
- Ramajayam,Giridhar, Rajani,Yadav,Balaraman,Djaballah, Hakim,Shum, David,Radu, Constantin
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p. 2004 - 2010
(2008/12/22)
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- Tandem pinacol coupling-rearrangement of aromatic aldehydes with hydrogen catalyzed by a combination of a platinum complex and a polyoxometalate
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Together with a strongly oxidizing polyoxometalate, H5PV 2Mo10O40, PtII(N-(2,6- diisopropylphenyl)pyrazin-2-ylmethanimine)Cl2 forms a combined catalyst that was active in the tandem pinacol coupling-rearrangement of aryl aldehydes to give mostly the corresponding diarylacetaldehyde in high yields using molecular hydrogen as the reducing agent. The Royal Society of Chemistry.
- Branytska, Olena,Shimon, Linda J. W.,Neumann, Ronny
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p. 3957 - 3959
(2008/10/09)
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- Synthesis of novel substituted diaryl-1,4-diazepines
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In this paper a convenient route to new 2,3-diaryl-substituted 1,4-diazepines is described through cyclization of ethanedione derivatives and 1,3-propanediamine. The ethanedione derivatives required were synthesized by microwave-assisted oxidation from ethanones.
- Ramajayam,Giridhar, Rajani,Yadav
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p. 901 - 906
(2008/02/12)
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- A fast and simple method for the acylation of alcohols with acid chlorides promoted by metallic samarium
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Acylation of primary, secondary, allyl and benzyl alcohols with acid chlorides promoted by samarium metal under neutral condition gave carboxylic acid esters in good to excellent yields. Acylation of a tertiary alcohol did not occur under the same reaction conditions.
- Jia, Xue-Shun,Wang, Hai-Long,Huang, Qing,Kong, Ling-Long,Zhang, Wei-He
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p. 135 - 138
(2007/10/03)
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- HETEROCYCLIC COMPOUND DERIVATIVES AND MEDICINES
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The present invention provides a compound which is useful as a PGI2 receptor agonist, and a pharmaceutical composition. The present invention is directed to a pharmaceutical composition comprising a compound represented by the following formula [1]: (R1 and R2 are the same or different and each represents optionally substituted aryl, Y represents N or CH, Z represents N or CH, A represents NH, NR5, O, S, or ethylene, R5 represents alkyl, D represents alkylene or alkenylene, E represents phenylene or single bond, G represents O, S, or CH2, R3 and R4 are the same or different and each represents hydrogen or alkyl, Q represents carboxy, alkoxycarbonyl, tetrazolyl, carbamoyl, or N-(alkylsulfonyl)carbamoyl), or a pharmaceutically acceptable salt thereof as an active ingredient.
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- Reactions of aroyl chlorides with samarium metal in DMF-controllable syntheses of O-aroylbenzoins, 1,2-diarylethanones, and (z)-α, α′-stilbenediol dibenzoates
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Reduction of aroyl chlorides carried out in DMF with samarium metal has been studied. Samarium metal, which requires not any intended activation or pretreatment, was found to react with aroyl chloride in a controllable manner. Correspondingly, O-aroylbenzoins, 1,2-diarylethanones, or (Z)-α, α′-stilbenediol dibenzoates were afforded as the major products under controlled conditions.
- Liu, Yongjun,Wang, Xiaoxia,Zhang, Yongmin
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p. 4009 - 4022
(2007/10/03)
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- Organophosphorous chemistry: Selective transformation of benzoin to benzil, desyl bromide, or benzyl phenyl ketone
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Reaction of benzoin with dibromotriphenylphosphorane under various conditions has been closely investigated. Benzoin was selectively converted to desyl bromide by treatment with dibromotriphenylphosphorane in the presence of triethylamine, while benzyl phenyl ketone was formed in the presence of an excess amount of triphenylphosphine. On the other hand, benzoin was effectively oxidized to benzil by treatment with only bromine. The mechanism of producing these was also proposed. Desyl bromide was formed from the reaction of benzoin with dibromotriphenylphosphorane as a primary product and converted to benzyl phenyl ketone via the Perkow reaction, and benzil was formed by the oxidation of benzoin by bromine. When triethylamine or triphenylphosphine was used as an added base, these bases trapped free bromine, and the oxidation product, benzil, was formed in low yield. In the presence of triphenylphosphine as a base, the Perkow reaction of desyl bromide proceeded smoothly to give benzyl phenyl ketone preferentially, while in the presence of triethylamine, replacement of the hydroxy group to bromide occurred mainly.
- Furukawa, Isao,Sasaki, Mitsuhiro,Inoue, Takeshi,Ohta, Tetsuo
-
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- A new method of synthesizing deoxybenzoins from 1,3-dimethyl-2-(α- benzyloxybenzyl)imidazolium and 1,3-dimethyl-2-(α- benzyloxybenzyl)benzimidazolium iodides based on Wittig-type rearrangement
-
The treatment of 1,3-dimethyl-2-(α-benzyloxybenzyl)benzimidazolium iodides 1 with a base gave deoxybenzoins 2 in moderate yields. Sodium hydride (NaH), potassium carbonate (K2CO3), and cesium carbonate (Cs2CO3) were effective bases in this reaction. Deoxybenzoins 2 were produced through rearrangement of the benzyl group followed by expulsion of the 1,3- dimethylbenzimidazolium ylide (A). The rearrangement proceeds in a way similar to Wittig rearrangement. Deoxybenzoins 2 were also formed in good yields from 1,3-dimethyl-2-(α-benzyloxybenzyl)imidazolium iodides 4 upon similar treatment. However, the quaternary salts having a thiazolium moiety 5a and a pyridinium moiety 6a failed to produce deoxybenzoin (2a).
- Miyashita, Akira,Matsuoka, Yoshiyuki,Suzuki, Yumiko,Iwamoto, Ken-Ichi,Higashino, Takeo
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p. 1235 - 1242
(2007/10/03)
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- Formation of deoxybenzoins from 1,3-dimethyl-2-(α-benzyloxybenzyl)benzimidazolium iodides through rearrangement followed by expulsion of azolium ylide
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Treatment of several 1,3-dimethyl-2-(α-benzyloxybenzyl)benzimidazolium iodides 1 with K2CO3 gave deoxybenzoins 2 in moderate yields. Deoxybenzoins 2 were produced through rearrangement of benzyl groups followed by expulsion of 1,3-dimethylbenzimidazolium ylide (4). The reaction is classified as a Wittig rearrangement.
- Miyashita,Matsuoka,Iwamoto,Higashino
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p. 1960 - 1962
(2007/10/02)
-
- Intermolecular Reductive Cross Coupling of Carbonyl Compounds with Nitriles Induced by Low-valent Titanium
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Intermolecular cross coupling of carbonyl compounds with nitriles promoted by TiCl4-Zn leads to ketones.
- Gao, Ju,Hu, Ming-yang,Chen, Jian-xie,Yuan, Su,Chen, Wei-xing
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p. 1617 - 1620
(2007/10/02)
-
- IODOTRIMETHYLSILANE REDUCTION OF BENZOINS: SYNTHESIS OF DEOXYBENZOINS AND TETRAARYLFURANS
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Benzoins react readily with idotriethylsilane to produce, in many cases, mixtures of deoxybenzoins and tetraarylfurans.
- Krepski, Larry R.,Heilmann, Steven M.,Rasmussen, Jerald K.,Tumey, Michael L.,Smith, Howell K.
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p. 377 - 386
(2007/10/02)
-
- Reaction of Aryl Aldehydes with Thiocyanates in the Presence of Tributylphosphine
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Aryl aldehydes react with methyl thiocyanate in the presence of tributylphosphine to afford S-methyl thiobenzoates and arylacetonitriles in good yields.This is a novel disproportionation reaction involving carbon-carbon bond formation.These compounds thus obtained are easily converted into deoxybenzoins using sodium hydride.On the other hand, p-dialkylaminobenzaldehydes react with methyl thiocyanate under the same conditions to furnish both the corresponding trans-dicyanostilbenes and succinonitriles in moderate yields.Finally, the reaction was carried out with aryl thiocyanates resulting in the formation of addition products.
- Yokoyama, Masataka,Ohteki, Hiroko,Kurauchi, Masahiko,Hoshi, Kazuko,Yanagisawa, Eizaburo,et al.
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p. 2635 - 2640
(2007/10/02)
-
- Vinylcations, 39. Zinc Chloride Catalysed Addition of Hydrogen Chloride to Cyclopropylalkynes
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Zinc chloride catalysed addition of hydrogen chloride to 1-cyclopropylalkynes 5a-e (R = CH3, c-C3H5, phenyl, p-tolyl, 4-methoxyphenyl) is studied and the results are compared with those of the addition of HCl/ZnCl2 to several substituted arylalkynes 10a-h.Thus, the alkynes are reacted with HCl/ZnCl2 in dichloromethane and the reaction products are investigated also with respect to their stereochemistry.All alkynes yield predominantly the direkt hydrogen chloride addition products.The 1-cyclopropylalkynes 5a-d give (E)-1-chloro-1-cyclopropyl-1-alkenes 15, and (E)-1-chloro-2-cyclopropyl-1-(4-methoxyphenyl)ethene (16e) is obtained as the major product from 5e (R = 4-CH3OC6H4).Moreover, ring opening to homoallenyl chlorides 19 and, as a side reaction, formation of the ketones 17 and 18 by the addition of water are observed.In a secondary addition reaction, the dichlorides 20 are also obtained by homoallyl rearrangement.The arylalkynes 10a-g react preferentially with formation of (E)-1-aryl-1-chloroalkenes 21.Relative rates are obtained by inter- and intramolecular competition reactions of the alkynes 23 and 5b-e with HCl/ZnCl2 showing the order of stabilization by substituents of the intermediate vinyl cation 2 to be 4-ClC6H4 E2 mechanism.The preferential formation of the addition products E-15, E-16, and E-21 is attributed to a syn-vinyl cation ion pair and to steric approach control of the β-substituents in the vinyl cation intermediate 2.
- Hanack, Michael,Weber, Erhard
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p. 777 - 797
(2007/10/02)
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- DEOXYBENZOINS FROM AROMATIC ALDEHYDES
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Aromatic aldehydes were easily converted into the corresponding deoxybenzoins by treatment with methyl thiocyanate in the presence of tributylphosphine, followed by addition of sodium hydride.
- Yokoyama, Masataka,Hoshi, Kazuko,Imamoto, Tsuneo
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p. 1615 - 1616
(2007/10/02)
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