- Synthesis method of o-Dibromo compound
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The present invention discloses a synthesis method of o-dibromo compounds, said synthesis method comprising the following steps: preparation of olefins, brominated salts and a mixed solution of bromate; to the mixed solution of dropwise addition of hydrochloric acid solution for reaction; to the end of the reaction, the extraction of o-dibromo compounds in the reaction product; the synthesis method to inexpensive brominated salts (industrial or recycled brominated salts) and bromate as a bromine source, enhance the full use of applicable resources; after the end of the reaction after a simple filtration treatment to obtain a sufficient purity of the product, It can reduce production costs; at the same time, facilitate the transportation and storage of raw materials, and improve the working environment. The synthesis method of the present invention is simple and easy to operate, high safety, small pollution, simple post-treatment, low production cost, product yield and purity can meet the production needs, is both cost advantages and safety and environmental advantages of the industrializable process.
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Paragraph 0052-0059
(2022/01/04)
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- A Facile Access to trans -3-Styryl-4-hydrazinocyclopentenes via Palladium-Catalyzed Ring Opening of Diazanorbornenes with (Z)-β-Bromostyrenes/2,3-Dibromohydrocinnamic Acids
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trans -3-Styryl-4-hydrazinocyclopentenes have been synthesized via palladium-catalyzed desymmetrization of diazanorbornenes with (Z)-β-bromostyrenes. The reaction also works well with (Z)-β-bromostyrenes generated in situ from 2,3-dibromohydrocinnamic acids. The synthesized hydrazinocyclopentenes provide an easy route towards synthetic intermediates of many scaffolds of biological potential.
- Saranya,Chand, S. Sarath,Gopalan, Greeshma,Jijitha,Radhakrishnan
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p. 184 - 192
(2017/10/13)
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- Chloro/bromotrimethylsilane-Cu(NO3)2·3H2O: Safe and efficient reagent system for the decarboxylative ipso-nitration and dibromination of cinnamic acids
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Further synthetic potential of halotrimethylsilane-nitrate salt mixture is revealed. A mixture of TMSX-Cu(NO3)2·3H2O system is found to be an efficient reagent system for both the decarboxylative nitration (ipso-nitration) when X?=?Cl, and dibromination of cinnamic acids, with X?=?Br, under mild conditions. The reactions are safe and simple, affording the corresponding products (E)-β-nitrostyrenes, and anti-2,3-dibromo-3-phenylpropanoic acids in high yields with high selectivity in a relatively short time. Use of hazardous and toxic nitrating systems such as acetyl nitrate and brominating agents such as molecular bromine can be avoided.
- Roshandel, Sahar,Gurung, Laxman,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
p. 2842 - 2845
(2017/06/27)
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- Carbene-catalyzed LUMO activation of alkyne esters for access to functional pyridines
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A carbene-catalyzed LUMO activation of α,β-unsaturated alkyne esters is reported. This catalytic process allows for effective reactions of alkyne esters with enamides to synthesize functional pyridines via simple protocols. A previously unexplored unsaturated alkyne acyl azolium intermediate is involved in the key step of the reaction.
- Mou, Chengli,Wu, Jichang,Huang, Zhijian,Sun, Jun,Jin, Zhichao,Chi, Yonggui Robin
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p. 13359 - 13362
(2017/12/26)
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- Engaging Alkenyl Halides with Alkylsilicates via Photoredox Dual Catalysis
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Single-electron transmetalation via photoredox/nickel dual catalysis provides the opportunity for the construction of Csp3-Csp2 bonds through the transfer of alkyl radicals under very mild reaction conditions. A general procedure for the cross-coupling of primary and secondary (bis-catecholato)alkylsilicates with alkenyl halides is presented. The developed method allows not only alkenyl bromides and iodides but also previously underexplored alkenyl chlorides to be employed. (Chemical Equation Presented).
- Patel, Niki R.,Kelly, Christopher B.,Jouffroy, Matthieu,Molander, Gary A.
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supporting information
p. 764 - 767
(2016/03/01)
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- Palladium-Catalyzed Two-Component Domino Coupling Reaction of (Z)-β-Bromostyrenes with Norbornenes: Synthesis of 1,5-Enynes
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Polyfunctional molecules, 1,5-enynes, have been achieved via a palladium(0)-catalyzed domino coupling reaction of (Z)-β-bromostyrenes with norbornenes in the presence of cesium carbonate and N,N-dimethylformamide. The process involves a double Heck-type procedure, two-fold C(sp2) H activation and formation of two carbon-carbon bonds. There are possibilities of diversified transformation for the domino coupling of (Z)-β-bromostyrenes with norbornenes, the procedure is successfully driven to 1,5-enynes via accurate adjustment of the reaction conditions. (Figure presented.) .
- Mao, Jiangang,Li, Huifang,Wen, Herui,Li, Min,Fan, Xiaolin,Bao, Weiliang
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p. 1873 - 1879
(2016/07/06)
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- Pd-Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates
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Pd-catalyzed difluoromethylation of di-, tri- or tetra-substituted vinyl bromides, triflates, tosylates and nonaflates under mild conditions is described. The reaction tolerates a wide range of functional groups, such as bromide, chloride, fluoride, ester, amine, nitrile, and protected carbonyl, thus providing a general route for the preparation of difluoromethylated alkenes. Vinyl fantasy: Pd-catalyzed difluoromethylation of di-, tri-, or tetra-substituted vinyl bromides, triflates, tosylates, and nonaflates under mild conditions is described. The reaction tolerates a wide range of functional groups, such as bromide, chloride, fluoride, ester, amine, nitrile, and protected carbonyl, thus providing a general route for the preparation of difluoromethylated alkenes.
- Chang, Dalu,Gu, Yang,Shen, Qilong
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supporting information
p. 6074 - 6078
(2015/04/14)
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- Expedient Iodocyclization Approach Toward Polysubstituted 3H-Benzo[e]indoles
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A facile and expedient iodocyclization of 4-(2-prop-1-ynylphenyl)-1H-pyrroles towards the synthesis of polysubstituted 3H-benzo[e]indoles is reported. The transformation was optimized and the best results were obtained by using iodine (1.2 equiv,) in dichloromethane, and potassium carbonate as base. The starting 1,2,3,4-tetrasubstituted pyrroles were efficiently obtained by means of a nickel(II) chloride-promoted four-component (nitromethane, amine, 2-alkynylbenzaldehyde and ethyl acetoacetate) reaction. Further functionalization of the resulting 5-iodoheterocycles was also explored.
- Martins, Guilherme M.,Zeni, Gilson,Back, Davi F.,Kaufman, Teodoro S.,Silveira, Claudio C.
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supporting information
p. 3255 - 3261
(2015/11/03)
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- SPIROCYCLIC EBI2 MODULATORS
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Provided herein are small molecule Epstein-Barr virus-induced G-protein coupled receptor 2 (EBI2) modulator compounds, compositions comprising the compounds, and methods of using the compounds and compositions comprising the compounds. In some embodiments
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Paragraph 00236
(2015/04/15)
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- Palladium(0)-Catalyzed Methylcyclopropanation of Norbornenes with Vinyl Bromides and Mechanism Study
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An unusual methylcyclopropanation from [2 + 1] cycloadditions of vinyl bromides to norbornenes catalyzed by Pd(OAc)2/PPh3 in the presence of CH3ONa and CH3OH has been established. A methylcyclopropane subunit was installed by a 3-fold domino procedure involving a key protonation course. Preliminary deuterium-labeling studies revealed that the proton came from methyl of CH3OH and also exposed an additional hydrogen/deuterium exchange process. These two proton-concerned reactions were fully chemoselective.
- Mao, Jiangang,Xie, Hujun,Bao, Weiliang
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p. 3678 - 3681
(2015/08/18)
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- Palladium(0)-catalyzed methylenecyclopropanation of norbornenes with vinyl bromides
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Highly strained methylenecyclopropane derivatives have been achieved via a novel and efficient Pd(0)-catalyzed domino reaction. The formal [2 + 1] cycloaddition reaction of vinyl bromides to norbornenes involves a Heck-type coupling and a C(sp2)-H bond activation.
- Mao, Jiangang,Bao, Weiliang
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p. 2646 - 2649
(2014/06/09)
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- Palladium-catalyzed [2+1+1] annulation of norbornenes with (z)-bromostyrenes: Synthesis of bismethylenecyclobutanes via twofold C(sp2)-H bond activation
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The first Pd-catalyzed intermolecular [2+1+1] annulation reaction of (Z)-bromostyrene derivatives and norbornenes has been realized. Bismethylenecyclobutane derivatives were obtained with high yields. The domino coupling reaction involves a double Heck-type coupling process, twofold C(sp2)-H bond activation and formation of three carbon-carbon bonds.
- Mao, Jiangang,Bao, Weiliang
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p. 15726 - 15729
(2015/01/08)
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- C-1 alkynylation of N-methyltetrahydroisoquinolines through CDC: A direct access to phenethylisoquinoline alkaloids
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Direct cross-coupling between N-methyltetrahydroisoquinolines and alkynes using CuI-DEAD is presented. It affords the regioselective C-1-alkynylated products in good yield. This regio-selectivity is in contrast to the results reported earlier in the reaction of N,N-dimethylbenzyl amine where the N-methyl alkynylated product was formed exclusively or predominantly. The C-1-substituted propargylic isoquinolines were easily reduced to phenethylisoquinolines with Pd/C. This reaction sequence provides a short route to synthesize methopholine, homolaudanosine and other phenethylisoquinoline alkaloids. Georg Thieme Verlag Stuttgart · New York.
- Singh, Kamal Nain,Singh, Paramjit,Kaur, Amarjit,Singh, Pushpinder
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supporting information; experimental part
p. 760 - 764
(2012/07/02)
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- Convenient synthesis of terminal alkynes from anti-3-aryl-2,3- dibromopropanoic acids using a K2CO3/DMSO system
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A convenient, efficient, and generally applicable method was developed for the synthesis of terminal alkynes from anti-3-aryl-2,3-dibromopropanoic acids in the presence of DMSO and K2CO3.
- Cheng, Xuezhi,Jia, Jun,Kuang, Chunxiang
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experimental part
p. 2350 - 2354
(2012/02/03)
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- Synthesis and fluorescence of the new environment-sensitive fluorophore 6-chloro-2,3-naphthalimide derivative
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Convenient and efficient synthesis of a new environmentally sensitive chlorine-substituted 2,3-naphthalimide-based fluorophore is reported. Benzotriazole carboxyl group activation of the 6-chloro-fluorophore enabled quick labeling of free and Fmoc-protected amino acids. The photophysical properties of the compounds obtained include high quantum yields in solvents of different polarity: water, methanol, acetonitrile and hexane.
- Katritzky, Alan R.,Ozcan, Sevil,Todadze, Ekaterina
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supporting information; experimental part
p. 1296 - 1300
(2010/06/15)
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- Synthesis of (Z)-1-bromo-1-alkenes and terminal alkynes from anti-2,3-dibromoalkanoic acids by microwave-induced reaction
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(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time by microwave irradiation of the corresponding anti-2,3-dibromoalkanoic acids in a Et3N/DMF system. A one-pot synthesis of terminal alkynes and enynes from 2,3-dibromoalkanoic acids were also developed by microwave-induced reaction.
- Kuang, Chunxiang,Yang, Qing,Senboku, Hisanori,Tokuda, Masao
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p. 4043 - 4052
(2007/10/03)
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- Rapid debromination of vic-dibromoalkanes with zinc powder in acetic acid under microwave irradiation
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Microwave irradiation of vic-dibromoalkanes in acetic acid containing zinc powder for 1-2 min gave the corresponding alkenes in high yields.
- Kuang, Chunxiang,Yang, Qing,Senboku, Hisanori,Tokuda, Masao
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p. 282 - 284
(2007/10/03)
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- Gas-solid reactions of single crystals: A study of the reaction of bromine with single crystals of trans-cinnamic acid and a range of its derivatives by infrared and Raman microspectroscopy
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Single crystals of trans-cinnamic acid and of a range of derivatives of this compound containing halogen substituents on the aromatic ring have been reacted with 165 Torr pressure of bromine vapour in a sealed desiccator at 20°C for 1 week. Infrared and Raman microspectroscopic examination of the crystals shows that bromination of the aliphatic double bond, but not of the aromatic ring, has occurred. It is demonstrated also that the reaction is truly gas-solid in nature. A time-dependent study of these reactions shows that they do not follow a smooth diffusion-controlled pathway. Rather the reactions appear to be inhomogeneous and to occur at defects within the crystal. The reaction products are seen to flake from the surface of the crystal. It is shown, therefore, that these are not single crystal to single crystal transitions, as have been observed previously for the photodimerisation of trans-cinnamic acid and several of its derivatives. It is shown that there are no by-products of the reaction and that finely ground samples react to form the same products as single crystals. The Owner Societies 2005.
- Jenkins, Samantha L.,Almond, Matthew J.,Hollins, Peter
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p. 1966 - 1970
(2007/10/03)
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- Convenient and stereoselective synthesis of (Z)-1-bromo-1-alkenes by microwave-induced reaction
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(Z)-1-Bromo-1-alkenes were stereoselectively prepared in high yields in a short reaction time (0.2-1.0 min) by microwave irradiation of the corresponding 2,3-dibromoalkanoic acids in DMF in the presence of triethylamine.
- Kuang, Chunxiang,Senboku, Hisanori,Tokuda, Masao
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p. 3893 - 3896
(2007/10/03)
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- A mild procedure for the stereospecific transformation of trans cinnamic acid derivatives to cis β-bromostyrenes
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A new mild procedure has been developed for the synthesis of cis β- bromostyrene analogs with complete Z/E selectivity and good to excellent yields (58.4 - 90.9 %). The process involves carboxyl-halo-elimination of cinnamic acid dibromides by using triethylamine in N,N-dimethylformamide at room temperature. A one-pot procedure has also been described for the direct transformation of cinnamic acids to β-bromostyrenes.
- Kim, Sun Hee,Wei, Han-Xun,Willis, Steven,Li, Guigen
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p. 4179 - 4185
(2007/10/03)
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- Iodide-induced Debromination of Cinnamic Acid and Substituted Cinnamic Acid Dibromides in 2-Methoxyethanol
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The second order rate constants for the iodide-induced debromination of cinnamic acid and substituted cinnamic acid dibromides in 2-methoxyethanol are reported; the reactivities follow the order: p-OCH3 > o-CH3 > p-CH3 > p-NO2 > p-Cl > m-NO2 > -H > m-CH3 > m-OCH3 > o-Cl.The m-CH3 and p-Cl derivatives have higher enthalpies and lower negative entropies of activation whereas methoxy substituted derivatives are characterised by lower enthalpies and higher negative entropies of activation than the unsubstituted acid.The free energy of activation is nearly constant.
- Subramanian, K.,Mathai, I. M.
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p. 909 - 911
(2007/10/02)
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- Synthesis of 3-Arylcoumarins, Thiacoumarins and Carbostyrils
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3-Arylcarbostyrils (2a-f), coumarins (2g-j) and thiacoumarin (2k) have been prepared by a generalised method from α,β-dibromohydrocinnamoyl derivatives (1a-k).The intermediate dihydrocoumarins and dihydrocarbostyrils (3, Y = O, NH) have been prepared which on acid treatment furnish 2.However, treatment of 3 with a base affords the 4-arylcoumarins and carbostyrils (4).
- Natarajan, M.,Manimaran, T.,Ramakrishnan, V. T.
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p. 529 - 534
(2007/10/02)
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- A CONVENIENT METHOD FOR THE CONVERSION OF trans to cis-CINNAMIC ACIDS
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trans-Cinnamic acids react in sequence with bromine, base, and carbon monoxide to give cis-acids in reasonable yields.
- Galamb, Vilmos,Alper, Howard
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p. 2965 - 2968
(2007/10/02)
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- Mechanisms of 1,1-Reductive Elimination from Palladium: Coupling of Styrylmethylpalladium Complexes
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The complexes (E)- and (Z)-styrylbromobis(triphenylphosphine)palladium(II) react with methyllithium in benzene at ambient temperature to give (E)- and (Z)-propenylbenzene, respectively.A similar reaction at -78 deg C afforded (E)- and (Z)-styrylmethylbis(diphenylmethylphosphine)palladium(II) as a cis-trans mixture.On raising the temperature of solutions of (E)- and (Z)-2b, (E)- and (Z)-propenylbenzenes are produced, respectively, and the intermediate olefin complexes (E)- and (Z)-propenylbenzenebis(diphenylmethylphosphine)palladium(0) can be observed by NMR the reductive elimination reaction is intramolecular as determined by a crossover experiment and first order in dialkylpalladium(II) complex when diphenylmethylphosphine is present.The reaction of (E)-2b and trideuteriomethyl iodide gives some 3,3,3-trideuteriopropenylbenzene, again implicating a palladium(IV) intermediate as a possible reductive elimination intermediate in a catalytic coupling cycle.
- Loar, Marilyn K.,Stille, J. K.
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p. 4174 - 4181
(2007/10/02)
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