- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
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Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
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supporting information
p. 5416 - 5421
(2018/08/12)
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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
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Paragraph 0067
(2018/01/03)
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- A new regiospecific synthesis method of 1H-pyrazolo[3,4-b]quinoxalines – Potential materials for organic optoelectronic devices, and a revision of an old scheme
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A series of 6-substituted-1,3-diphenyl-1H-pyrazolo[3,4-b]quinoxalines were prepared using a new synthetic pathway: reductive cyclization of appropriate 5-(o-nitrophenyl)-pyrazoles with ferrous oxalate or triphenylphosphine. The main advantage of this procedure is that, contrary to the older protocols of pyrazolo[3,4-b]quinoxaline synthesis, this method allows for a substituent to be introduced to the carbocyclic ring without the formation of isomers. The pyrazole ring can also be modified to some extent. Furthermore, we propose a new mechanism for the oldest reported pyrazolo[3,4-b]quinoxaline synthesis, based on the condensation between o-phenylenediamine and 3,4-pyrazolin-5-diones.
- Danel, Andrzej,Wojtasik, Katarzyna,Szlachcic, Pawe?,Gryl, Marlena,Stadnicka, Katarzyna
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p. 5072 - 5081
(2017/07/28)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- Highly stereoselective 7-endo-trig /ring contraction cascade to construct pyrrolo[1,2- a ]quinoline derivatives
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With the cooperation of Cram's phenonium ion, a novel cascade reaction was illustrated to construct pyrrolo[1,2-a]quinolines as a sole diastereoisomer in good to excellent yields. Preliminary mechanistic studies revealed that the γ-lactam ring and electron-rich arene are important driving forces for ring contraction.
- Li, Xinyu,Li, Cheng,Zhang, Wenjing,Lu, Xiang,Han, Shiqing,Hong, Ran
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supporting information; experimental part
p. 1696 - 1699
(2010/09/05)
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- Synthetic study on tetrapetalones: Stereoselective cyclization of N-acyliminium ion to construct substituted 1-benzazepines
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The synthesis of the tetracyclic core of complex antibiotic tetrapetalones has been achieved In three steps starting from the simple Intermediate γ-hydroxy amide, which can be accessed through a high-yielding six-step sequence. The successful synthesis relies on a novel strategy based on the N-acyliminium ion cyclizatlon.
- Cheng, Li,Xlnyu, L.I. And,Ran, Hong
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supporting information; experimental part
p. 4036 - 4039
(2009/12/09)
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- FLUORINATED TRICYCLIC NEUROLEPTICS WITH PROLONGED ACTION: DERIVATIVES AND ANALOGUES OF 2-(4-(7-FLUORO-2-ISOPROPYL-10,11-DIHYDRODIBENZOTHIEPIN-11-YL)PIPERAZINE-1-YL)ETHANOL
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The preparation of 4-fluoro-2-nitrobenzonitrile (V), an intermediate in the synthesis of the title compound I, from 4-fluoro-2-nitroaniline via 5-fluoro-2-iodonitrobenzene (VII) was elaborated.Syntheses of 1,1,1,3,3,3-hexadeutero-2-propyl (XX) and 1,3,4-trideutero (XXVIII) analogues of compound I from hexadeuteroacetone, and pentadeuterobromobenzene, respectively, were carried out.Compound I was esterified with acetic anhydride, decanoic acid and 3,4,5-trimethoxybenzoyl chloride to give the esters II-IV.Acylation of compound XXX with acetyl chloride, 4-fluorophenoxyacetyl chloride and (4-fluorophenylthio)acetyl chloride and the following reduction of the amides with lithium aluminium hydride gave compounds XXXII, XXXIX, and XL.Substitution reactions of 11-chloro-7-fluoro-2-isopropyl-10,11-dihydrodibenzothiepin with the corresponding N-monosubstituted piperazines resulted in compounds XXXIII-XXXV, XXXVII, XXXVIII, XLI and XLII.Alkylation of XXX with 2-(2-chloroethyl)-1,3-dioxolane afforded compound XXXVI.Pharmacological testing of the new compounds, derivatives and analogues of the neuroleptic agent isofloxythepin (I), for discoordinating and cataleptic activities, showed especially for compounds II, XXXIV and XXXVI very intensive and long-lasting effects.The decanoate III has properties of a depot neuroleptic agent.
- Protiva, Miroslav,Jilek, Jiri,Rajsner, Miroslav,Sindelar, Karel,Bartl, Vaclav,et al.
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p. 1811 - 1833
(2007/10/02)
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