- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- Copper and L-(?)-quebrachitol catalyzed hydroxylation and amination of aryl halides under air
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L-(?)-Quebrachitol, a natural product obtained from waste water of the rubber industry, was utilized as an efficient ligand for the copper-catalyzed hydroxylation and amination of aryl halides to selectively give phenols and aryl amines in water or 95percent ethanol. In addition, the hydroxylation of 2-chloro-4-hydroxybenzoic acid was validated on a 100-g scale under air.
- Bao, Xuefei,Chen, Guoliang,Dong, Jinhua,Du, Fangyu,Li, Hui,Liang, Xinjie,Wu, Ying,Zhang, Yongsheng
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supporting information
(2020/08/03)
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- Deprotection of N-Boc Groups under Continuous-Flow High-Temperature Conditions
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The scope of thermolytic, N-Boc deprotection was studied on 26 compounds from the Pfizer compound library, representing a diverse set of structural moieties. Among these compounds, 12 substrates resulted in clean (≥95% product) deprotection, and an additional three compounds gave ≥90% product. The thermal de-Boc conditions were found to be compatible with a large number of functional groups. A combination of computational modeling, statistical analysis, and kinetic model fitting was used to support an initial, slow, and concerted proton transfer with release of isobutylene, followed by a rapid decarboxylation. A strong correlation was found to exist between the electrophilicity of the N-Boc carbonyl group and the reaction rate.
- Li, Bryan,Li, Ruizhi,Dorff, Peter,McWilliams, J. Christopher,Guinn, Robert M.,Guinness, Steven M.,Han, Lu,Wang, Ke,Yu, Shu
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p. 4846 - 4855
(2019/01/30)
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- Preparation method of polyfluoroaniline
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The invention relates to a preparation method of polyfluoroaniline, according to the method, the polyfluoroaniline is prepared by a two-step common reaction from polyfluorobenzene as a raw material, the method has the characteristics of low reaction temperature, small pressure, low cost, and the like, is suitable for industrial production application, and is convenient for large-scale production;the polyfluoroaniline product obtained by the method has less impurities and high product purity.
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- Interaction of polyfluorinated 2-chloroquinolines with ammonia
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We have studied the interaction of polyfluorinated (in the benzene moiety) 2-chloroquinolines with liquid and aqueous ammonia as an approach to the synthesis of halogen-containing aminoquinolines. 5,7-Difluoro-, 5,6,8-trifluoro-, and 5,7,8-trifluoro-2-chloroquinolines mostly form products of substitution of the Cl atom, whereas 5,7-difluoro-2,6-dichloroquinoline, 5,6,7,8-tetrafluoro-, and 6,7-difluoro-2-chloroquinolines yield products of substitution of an F atom at various positions. The replacement of liquid ammonia with aqueous causes an increase in the proportion of the products of aminodechlorination relative to the products of aminodefluorination. For 2-chloro-6,8-difluoroquinoline this replacement leads to 2-amino-6,8-difluoroquinoline as the main product instead of the 8-amino-derivative. Activation energy values estimated by DFT calculations for the reactions in question agree with the reaction regioselectivity observed experimentally.
- Skolyapova, Alexandrina D.,Selivanova, Galina A.,Tretyakov, Evgeny V.,Bogdanova, Tatjana F.,Shchegoleva, Lyudmila N.,Bagryanskaya, Irina Yu.,Gurskaya, Larisa Yu.,Shteingarts, Vitalij D.
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p. 1219 - 1229
(2017/02/18)
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- Preparation method of 3,5-difluoroaniline
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The invention discloses a preparation method of 3,5-difluoroaniline and relates to the technical field of organic synthesis. The preparation method comprises steps as follows: 2,4-difluoroaniline, tap water, hydrochloric acid, bromine, sodium nitrite, sodium monophosphate and ammonium hydroxide are taken as raw materials, cuprous oxide is taken as a catalyst, the tap water and dichloroethane are taken as solvents, and a product of 3,5-difluoroaniline is prepared through steps of bromination, diazotization, ammoniation, extraction, distillation and the like. According to the method, the industrially available raw materials can be utilized for reaction, the process is simple, post-treatment is simple and convenient, conditions are mild, environmental pollution is small, and the product of 3,5-difluoroaniline is prepared with high yield, and meanwhile, industrial production can be realized.
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Paragraph 0029
(2018/02/04)
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- Synthesis of polyfluorinated 4-phenyl-3,4-dihydroquinolin-2-ones and quinolin-2-ones via superacidic activation of N-(polyfluorophenyl)cinnamamides
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The cyclization reactions of a series of polyfluorocinnamanilides in triflic acid (CF3SO3H) yield 4-phenyl-3,4-dihydroquinolin-2-ones, which include a polyfluorinated benzene moiety as a part of the quinoline scaffold. These compounds undergo dehydrophenylation in the presence of AlCl3 to give the corresponding polyfluoroquinolin-2-ones which are converted into polyfluorinated 2-chloroquinolines on treatment with POCl3. A mechanism for the cyclization reaction presuming the intermediacy of a superelectrophilic O,C-diprotonated form of the starting material is suggested.
- Safina, Larisa Yu.,Selivanova, Galina A.,Koltunov, Konstantin Yu.,Shteingarts, Vitalij D.
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supporting information; experimental part
p. 5245 - 5247
(2009/12/06)
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- SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS INHIBITORS
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The use of a compound of formula (I) 1 or a salt, ester or amide thereof; where X is O, or S, S(O) or S(O)2, or NR6 where R6 is hydrogen or C1-6 alkyl,; R5 is an optionally substituted 5-membered heteroaromatic ring, R1, R2 ,R3, R4 are independently selected from various specified moieties, in the preparation of a medicament for use in the inhibition of aurora 2 kinase. Certain compounds are novel and these, together with pharmaceutical compositions containing them are also described and claimed
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- Method of making 3,5-difluoroaniline from 1,3,5-trichlorobenzene
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A method for manufacturing 3,5-difluoroaniline by fluorinating 1,3,5-trichlorobenzene and then aminating the intermediate fluorinated benzene with aqueous or anhydrous ammonia to achieve the product in yields of greater than 80%.
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- Process for producing 3,5-difluoroaniline and derivative thereof
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A process for production of a 3,5-difluoroaniline compound with ease is disclosed, which comprise reacting an aminating agent with a 1,3,5-trifluorobenzene compound.
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- Process for producing 3,5-difluoraniline
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A process for producing 3,5-difluoroaniline, which comprises reacting a benzonitrile compound of the formula (I): STR1 wherein each of X1, X2 and X3 is hydrogen, chlorine, bromine or a cyano group, provided that at least one of X1 to X3 is a cyano group, with a mineral acid for hydrolysis and decarboxylation to obtain an aniline compound of the formula (II): STR2 wherein each of X4, X5 and X6 is hydrogen, chlorine or bromine, provided that at least one of X4 to X6 is hydrogen, and in the case of a compound of the formula (II) wherein X4, X5 and X6 are not simultaneously hydrogen, reacting such a compound with hydrogen in a presence of a catalyst for reduction to obtain 3,5 -difluoroaniline.
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- Process for preparing 3,5-difluoroaniline
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Process for preparing 3,5-difluoroaniline, wherein (1) 2,4,5-trichloronitrobenzene is reacted with an alkali metal fluoride in the presence or absence of a polar aprotic solvent at temperatures of about 100° C. to about 250° C., and, after filtering off precipitated salts and fractional distillation of the crude solution, (2) the resulting 5-chloro-2,4-difluoronitrobenzene is chlorinated with denitration to give 1,3-dichloro-4,6-difluorobenzene in the absence of a Lewis acid or of another chlorination catalyst, using anhydrous chlorine gas at temperatures of about 80° to about 250° C., and (3) this compound is nitrated to give 2,6-dichloro-3,5-difluoronitrobenzene in oleum with mixed acid (sulfuric acid/nitric acid) at temperatures of about 15° to about 80° C., and (4) this compound is reduced with hydrogen in the presence of palladium as catalyst and in the presence of an inorganic or organic base at temperatures of about 40° to about 250° C.
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- REACTIONS OF AROMATIC COMPOUNDS WITH NUCLEOPHILIC REAGENTS IN LIQUID AMMONIA. REACTION OF POLYFLUORINATED DERIVATIVES OF BENZENE WITH SODIUM AMIDE
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Under the influence of sodium amide in liquid ammonia at a temperature no higher than -33 deg C pentafluorobenzene, 1,2,4,5-tetrafluorobenzene, and 1,3-difluorobenzene undergo deprotonation with the formation of fluorinated phenyl anions, which are resistant to the elimination of a fluoride ion and can be detected by the formation of the products from interaction with electrophiles (with the initial compound in the first case and with methyl iodide in the other two cases). 1,3,5-Trifluorobenzene behaves similarly in reaction with one equivalent of sodium amide, but with two equivalents of sodium amide this compound and 1,2,3,5-tetrafluorob enzene undergo substitution of a fluorine atom by an amino group with the formation of 3,5-di- and 3,4,5-trifluoroanilines respectively.This is clearly due to the double deprotonation of these compounds with the formation of polyfluorinated m-phenylene dianions, which are then converted with the elimination of a fluoride ion into the corresponding dehydrophenyl anions.
- Shtark, A. A.,Chuikova, T. V.,Selivanova, G. A.,Shteingarts, V. D.
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p. 2271 - 2276
(2007/10/02)
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- Antimicrobial composition and method containing N-(3,5-dihalophenyl)-imide compounds
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Novel N-(3,5-dihalophenyl)imide compounds, which exhibit a strong antimicrobial activity against microorganisms including phytopathogenic fungi, parasites of industrial products and pathogenic microorganisms, represented by the formula, STR1 wherein X and X' each represent halogens and A represents a substituted ethylene such as chloroethylene, C1 - C4 alkylthioethylene, C1 - C2 alkyl-ethylene or 1,2-di-C1 - C2 -alkyl-ethylene, a cyclopropylene such as 1,3-dimethylcyclopropylene, trimethylene, a cyclohexylene-1,2-, cyclohexenylene-1,2-, cyclohexadienylene-1,2- or o-phenylene. The N-(3,5-dihalophenyl)imide compounds can be obtained by any of methods which produce imide compounds or reaction of an N-(3,5-dihalophenyl)maleimide compound with a mercaptan, a hydrogen halide, phosphorus chloride or thionylchloride.
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