- Practical two-step synthesis of an enantiopure aliphatic terminal (S)-epoxide based on reduction of haloalkanones with "designer cells"
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A practical biocatalytic method for the synthesis of aliphatic β-halogenated (S)-alcohols as epoxide precursors by means of an enantioselective reduction of the corresponding ketones with recombinant whole cells, bearing an alcohol dehydrogenase and a glucose dehydrogenase, was developed. The biotransformations operate at high substrate concentrations of up to 208 g/L, and afford the (S)-β-halohydrins with both high conversions of >95% and enantioselectivities of >99% ee. Base-induced cyclization of the β-halohydrin intermediates gave the desired (S)-epoxides in high yield and enantiomeric purity (>99% ee).
- Berkessel, Albrecht,Rollmann, Claudia,Chamouleau, Francoise,Labs, Stefanie,May, Oliver,Groeger, Harald
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- Thiophene-bithiazole based metal-free dye as DSSC sensitizer: Effect of co-adsorbents on photovoltaic efficiency
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A new molecule consisting of a bithiazole chromophore sandwiched between two thiophenes, functionalized with benzothiophene unit at one end and cyanoacrylic acid at the other end (BT1) was synthesized, photophysical properties were studied and employed as a photosensitizer in dye-sensitized solar cells (DSSCs). The molecule exhibited an intense absorption in the UV-visible region with absorption extending up to 500 nm. The ground and excited state potentials of BT1 were calculated to be 1.29 and -0.65 V, respectively vs. NHE using cyclic voltammetry. The ground state energy level is more positive than the triiodide electrolyte and excited state energy level is considerably more negative than the TiO2 satisfying the energetic requirements for a photosensitizer in DSSC. The solar cells fabricated from BT1 exhibited an efficiency of 1.13%. The effect of various co-adsorbents (CDCA,TP1 andTP2) on the DSSC performance was investigated in detail. In the presence of CDCA, the photovoltaic efficiency was enhanced to 1.25%, whereas, in the presence of TP1 and TP2, the efficiency lowered to 0.20% and 0.59%, respectively. The increased efficiency in the presence of CDCA could be attributed to the prevention of the aggregation of dye molecules induced by CDCA. On the other hand, TP1 and TP2 were found to be not as effective as CDCA to prevent aggregation leading to the lowering of photoconversion efficiency. [Figure not available: see fulltext.]
- Panicker, Jayanthy S.,Balan, Bijitha,Soman, Suraj,Ghosh, Tanwistha,Nair, Vijayakumar C.
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- CS-symmetric triarylborane substituted bisthiazole for selective detection of F?and CN?ions
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Triarylborane substituted bisthiazole 1 was designed and synthesized by the Sonogashira cross-coupling reaction for selective detection of F?and CN?ions in the presence of Cl?, Br?, I?and NO2?anions. The detection limits for F?and CN?were found to be 5.7?×?10?6?M and 2.1?×?10?6?M, respectively. The time dependent density functional theory (TD-DFT) calculation at B3LYP on the bisthiazole triarylborane 1 was studied for F?and CN?ions. In the case of 1 Boron is electron deficient, the addition of F?ion should increase the electron density on Boron which was confirmed by electrostatic potential surfaces of bisthiazole triarylborane dyad 1, 1-F.
- Maragani, Ramesh,Reddy, T. Sheshashena,Misra, Rajneesh
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- C2-Symmetric ferrocenyl bisthiazoles: Synthesis, photophysical, electrochemical and DFT studies
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A series of donor-acceptor ferrocenyl substituted bisthiazoles 3-8 were designed and synthesized by the Pd-catalyzed Suzuki, Heck, and Sonogashira cross-coupling reactions. Their photophysical, electrochemical and computational studies reveal strong donor-acceptor interactions. The photonic and electrochemical studies show that the ferrocenyl bisthiazoles with vinyl linkage ferrocenyl-bisthiazole 4, show better electronic communication compared to rest of the ferrocenyl bisthiazoles. The time dependent density functional theory (TD-DFT) calculation at B3LYP on the ferrocenyl substituted bisthiazoles 3-5 was performed, in which the ferrocenyl-bisthiazole 4 shows strong donor-acceptor interactions compared to the Fc-bisthiazoles 3 and 5. The thermal stability of the ferrocenyl substituted bisthiazoles 3-8 is reported, in which Fc-bisthiazole 8 shows high thermal stability. The single crystal structures of ferrocenyl-bisthiazoles 3 and 5 are reported.
- Maragani, Ramesh,Gautam, Prabhat,Mobin, Shaikh M.,Misra, Rajneesh
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Read Online
- Visible-light induced metal-free cascade Wittig/hydroalkylation reactions
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Cascade reactions are green and powerful transformations for building multiple carbon-carbon bonds in one step. Through a relay olefination and radical addition process, we were able to develop the cascade Wittig/hydroalkylation reactions induced by visible light. This metal-free radical approach features mild conditions, robustness, and excellent functionality compatibility. It allows access to saturated C3 homologation products directly from aldehydes or ketones. The synthetic utility of this method is demonstrated by a two-step synthesis ofindolizidine 209D.
- Miao, Pannan,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
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supporting information
p. 1638 - 1641
(2021/03/09)
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- A radical exchange process: Synthesis of bicyclo[1.1.1]pentane derivatives of xanthates
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Bicyclo[1.1.1]pentane (BCP) replacement as a bioisostere in drug molecules has an influence on their permeability, aqueous solubility and in vitro metabolic stability. Thus, the chemical installation of the BCP unit into a chemical entity remains a significant challenge from a synthetic point of view. Here, we have presented a new approach for the installation of the BCP unit on the xanthate moiety by means of a radical exchange process.
- Rout, Saroj Kumar,Marghem, Gilles,Lan, Junjie,Leyssens, Tom,Riant, Olivier
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supporting information
p. 14976 - 14979
(2019/12/24)
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- An efficient heterogeneous gold(I)-catalyzed hydration of haloalkynes leading to α-halomethyl ketones
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A highly efficient heterogeneous gold(I)-catalyzed hydration of haloalkynes has been developed that proceeds smoothly under mild and neutral conditions and provides a general and practical route for the synthesis of a variety of α-halomethyl ketones with high atom-economy, excellent yield, and recyclability of the gold(I) catalyst. The presented method delivers an attractive alternative to classical α-halogenation of ketones.
- Hu, Sifan,Liu, Dayi,Yan, Chenyu,Cai, Mingzhong
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supporting information
p. 2983 - 2991
(2018/12/04)
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- A new and versatile one-pot strategy to synthesize alpha-bromoketones from secondary alcohols using ammonium bromide and oxone
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A new, efficient and green protocol for the one-pot synthesis of α-bromoketones from secondary alcohols using cheap, air stable and non-toxic reagents such as NH4Br and oxone has been developed. This reaction proceeds via two consecutive steps such as oxidation of secondary alcohols and oxidative bromination of in situ generated ketones.
- Rammurthy, Banothu,Swamy, Peraka,Naresh, Mameda,Srujana, Kodumuri,Durgaiah, Chevella,Krishna Sai, Gajula,Narender, Nama
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p. 3710 - 3714
(2017/07/12)
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- 1,3-Dibromo-5,5-dimethylhydantoin mediated oxidative amidation of terminal alkenes in water
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A variety of terminal alkenes were converted to the corresponding amides in yields of 25 to 86% in water via treatment with 1,3-dibromo-5,5-dimethylhydantoin, followed by reaction with molecular iodine and aq. NH3 (or amine) in one pot. This metal- and organic solvent-free protocol is not only suitable for styrene derivatives, but also, for the first time, works well on terminal aliphatic alkenes.
- Ma, Chunhua,Fan, Guojie,Wu, Ping,Li, Zhi,Zhou, Yang,Ding, Qingjie,Zhang, Wei
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p. 9889 - 9894
(2017/12/12)
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- Catalytic dehydrogenative dual functionalization of ethers: Dealkylation-oxidation-bromination accompanied by C-O bond cleavage: Via aerobic oxidation of bromide
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Catalytic dehydrogenative dual functionalization (DDF) of ethers via oxidation, dealkylation, and α-bromination by the aerobic oxidation of bromide was developed to obtain the corresponding α-bromo ketones in high yields. In particular, the reaction of substituted tetrahydrofurans as cyclic ethers provided 3,3-dibromo tetrahydrofuran-2-ols in high yields selectively through the double α-bromination.
- Moriyama, Katsuhiko,Hamada, Tsukasa,Nakamura, Yu,Togo, Hideo
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supporting information
p. 6565 - 6568
(2017/07/10)
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- Water-controlled selective preparation of α-mono or α,α′-dihalo ketones: Via catalytic cascade reaction of unactivated alkynes with 1,3-dihalo-5,5-dimethylhydantoin
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The control of a reaction that can produce multiple products from the same starting material is a highly attractive and challenging concept in organic synthesis. An efficient protocol for the selective synthesis of α-mono or α,α′-dihalo ketones via a water-controlled three-component thiourea-catalyzed cascade reaction of unactivated alkynes, 1,3-dihalo-5,5-dimethylhydantoin and water has been developed. α-Monohaloketones were obtained in aqueous acetone at 45 °C; conversely, α,α′-dihalo ketones were formed with pure water as the sole solvent at room temperature.
- Wu, Chao,Xin, Xiu,Fu, Zhi-Min,Xie, Long-Yong,Liu, Kai-Jian,Wang, Zheng,Li, Wenyi,Yuan, Zhi-Hui,He, Wei-Min
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p. 1983 - 1989
(2017/06/09)
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- 1,3-Dibromo-5,5-dimethylhydantoin (DBH) mediated one-pot syntheses of α-bromo/amino ketones from alkenes in water
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α-Bromo ketones are versatile intermediates of high practical utility. Traditional approaches to these compounds are restricted to a relatively hazardous/complex reagent combination, a long reaction time, the use of non-environmentally friendly solvents, or a limited substrate scope. Herein, we describe the development of a new methodology for the preparation of α-bromo ketones from alkenes using 1,3-dibromo-5,5-dimethylhydantoin (DBH) as a bromine source and an oxidant simultaneously. This easy to carry out two-step one-pot protocol proceeds in water and provides high yield of a great variety of α-bromo ketones. Addition of an amine to the intermediate α-bromo ketone further enables the preparation of α-amino ketones in a one-pot sequence.
- Xu, Senhan,Wu, Ping,Zhang, Wei
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p. 11389 - 11395
(2016/12/18)
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- TsNBr2mediated oxidative functionalization of alkynes
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A new approach has been developed for oxidative transformation of alkynes by controlled manipulation of TsNBr2mediated process. Alkynes could be readily converted to ketones and α-bromoketones via an oxybromination–debromination sequence. When alkynes are treated successively with TsNBr2, KI and Na2SO3in a mixture of acetone and water at room temperature, corresponding ketones were obtained. On the other hand, treatment of alkynes with TsNBr2and Na2SO3in a mixture of ethyl acetate, acetone and water at room temperature could produce corresponding α-bromoketones. 1-Bromoalkynes could also be synthesized from corresponding alkynes within a very short time using TsNBr2at room temperature. In all cases, excellent yields of corresponding products are obtained.
- Rajbongshi, Kamal Krishna,Hazarika, Debojit,Phukan, Prodeep
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p. 4151 - 4158
(2016/07/06)
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- Inhibition of bacterial biofilms and microbial growth with imidazole derivatives
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Disclosure is provided for imidazole derivative compounds useful to inhibit the formation of biofilms and/or inhibit microbial growth, compositions including these compounds, devices including these compounds, and methods of using the same.
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Page/Page column 40; 41
(2016/04/26)
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- Metal-free protocol for the synthesis of α-bromo ketones from olefins using TsNBr2
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TsNBr2 reacts readily with olefins to produce α-bromo ketones at room temperature. The synthesis was carried out by treating an olefin with TsNBr2 in acetone-water mixture in 30:1 ratio. Excellent yield of corresponding α-bromo ketone could be achieved within a short time.
- Rajbongshi, Kamal Krishna,Hazarika, Debojit,Phukan, Prodeep
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supporting information
p. 356 - 358
(2015/04/27)
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- A non-fullerene acceptor with all "a" units realizing high open-circuit voltage solution-processed organic photovoltaics
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A novel non-fullerene small molecule electron acceptor TTzBT-DCAO, which contains all electron-withdrawing units of 2,1,3-benzothiadiazole, oligothiazole and alkyl cyanoacetate, has been synthesized and characterized. Its photophysical, electrochemical, and photovoltaic properties have been investigated. The material has favorable HOMO and LUMO levels of -5.88 and -3.60 eV, and shows strong absorption in the visible spectrum up to 650 nm. The small molecule:non-fullerene bulk-heterojunction organic photovoltaics (OPVs) were constructed based on two small molecules SF8TBT and TTzBT-DCAO. The influence of the donor:acceptor composition on device performance was investigated. The open-circuit voltages of the devices are over 1.20 V, which is among the highest values reported for single-junction OPVs. The results indicate that small molecules with all electron-withdrawing units could provide a novel route to efficient solution-processed OPVs with high open-circuit voltages.
- Chen, Lingcheng,Huang, Linquan,Yang, Dong,Ma, Shuying,Zhou, Xin,Zhang, Jian,Tu, Guoli,Li, Can
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p. 2657 - 2662
(2014/02/14)
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- Room-Temperature oxidation of secondary alcohols by bromate-bromide coupling in acidic water
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The use of environmentally benign reactions is currently an important topic in the field of synthetic chemistry. Here we report a high-yielding method to oxidize aliphatic or aromatic secondary alcohols into corresponding ketones using nonhazardous and inexpensive BrOH reagent at room temperature in water. BrOH reagent was derived from NaBr and NaBrO3 in aqueous acid. Based on the presented results, a mechanism was proposed for this oxidation. The reported method offers a facile, efficient procedure to produce various ketones with a low amount of side products. Taylor & Francis Group, LLC.
- Paeaekkoenen, Sanna,Pursiainen, Jouni,Lajunen, Marja
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experimental part
p. 534 - 540
(2011/12/04)
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- Direct conversion of olefins into α-bromo ketones using O-iodoxybenzoic acid and tetraethylammonium bromide
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Utilizing full potential of IBX, a mild, selective, and facile method has been developed for the direct conversion of olefins into the corresponding α-bromo ketones by using 1.1 equivalents each of o-iodoxybenzoic acid and tetraethylammonium bromide. Georg Thieme Verlag Stuttgart - New York.
- Deshmukh, Swapnil S.,Chaudhari, Kiran H.,Akamanchi, Krishnacharya G.
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experimental part
p. 81 - 83
(2011/03/20)
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- Synthesis, two-photon absorption, and optical power limiting of new linear and hyperbranched conjugated polyynes based on bithiazole and triphenylamine
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Two new linear and hyperbranched conjugated polymers P1 and P2 have been synthesized by Sonogashira coupling reaction, in which the main chain consists of bithiazole moieties as electron acceptors and triphenylamino groups as donors. The conjugated polymers were characterized by TGA, UV-vis absorption, fluorescence emission, electrochemical cyclic voltammetry, and two-photon absorption measurements. They exhibited excellent solubility in organic solvents and high thermal stability (5% of weight loss at 299 °C). The two-photon absorption cross sections (σ) measured by the open aperture Z-scan technique using 140 femtosecond (fs) pulse were determined to be 1014 and 552 GM per repeating unit for P1 and P2, respectively. This result shows that the σ of linear conjugated P1 is higher than that of hyperbranched P2, indicating that the linear polymer offers better intramolecular charge transfer ability. In THF, P1 and P2 exhibit intense frequency up-converted fluorescence under the excitation of 140 fs pulses at 800 nm with the peaks located at 580 and 548 nm, respectively. Meanwhile, the optical limiting behaviors for the polymers were studied by using a focused 800 nm laser beam of 140 fs duration. It was found that these polymers also exhibit good optical-limiting properties and make them potential candidates for optical limiters in the photonic fields.
- Jiang, Yihua,Wang, Yaochuan,Yang, Jiabao,Hua, Jianli,Wang, Bing,Qian, Shiqiong,Tian, He
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experimental part
p. 1830 - 1839
(2012/03/10)
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- OXAZOLOBENZIMIDAZOLE DERIVATIVES
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The present invention is directed to oxazolobenzimidazole derivatives which are potentiators of metabotropic glutamate receptors, particularly the mGluR2 receptor, and which are useful in the treatment or prevention of neurological and psychiatric disorders associated with glutamate dysfunction and diseases in which metabotropic glutamate receptors are involved. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which metabotropic glutamate receptors are involved.
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Page/Page column 27
(2010/04/27)
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- A nitroenolate approach to the synthesis of 4,5-disubstituted-2- aminoimidazoles. Pilot library assembly and screening for antibiotic and antibiofilm activity
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A library of 4,5-disubstituted-2-aminoimidazoles was synthesized using a nitroenolate route and then screened for antibiofilm and antimicrobial activity. These compounds displayed notable biofilm dispersal and planktonic microbicidal activity against various Gram-positive and Gram-negative bacteria.
- Su, Zhaoming,Rogers, Steven A.,McCall, W. Steve,Smith, Alicia C.,Ravishankar, Sindhu,Mullikin, Trey,Melander, Christian
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experimental part
p. 2814 - 2822
(2010/08/21)
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- Chemo- And stereodivergent preparation of terminal epoxides and bromohydrins through One-Pot biocatalysed reactions: Access to enantiopure Five- and Six-Membered N-Heterocycles
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Different enantiopure terminal epoxides or bromohydrins have chemoselectively been synthesised in one-pot starting from the corresponding a-bromo ketones through alcohol dehydrogenase (ADH)-catalysed processes adding an organic cosolvent and tuning appropriately the medium pH and the temperature. Thus, at neutral pH enantiopure bromohydrins were obtained while using basic conditions (pH 9.5-10) epoxides were isolated as the main product. Furthermore, by simple selection of the biocatalyst, chemo- and stereodivergent transformations were achieved to obtain, e.g., enantiopure prolinol or piperidin-3-ol.
- Bisogno, Fabricio R.,Cuetos, Anibal,Orden, Alejandro A.,Kurina-Sanz, Marcela,Lavandera, Ivan,Gotor, Vicente
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supporting information; experimental part
p. 1657 - 1661
(2010/09/18)
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- Facile one-pot synthesis of α-bromoketones from olefins using bromide/bromate couple as a nonhazardous brominating agent
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A new method for the preparation of α-bromoketones from olefins using bromide/bromate couple as a nonhazardous brominating agent has been developed. Several α-bromoketones were successfully prepared from a variety of olefins by this method. This procedure is an alternative to conventional molecular bromine.
- Patil, Rajendra D.,Joshi, Girdhar,Adimurthy, Subbarayappa,Ranu, Brindaban C.
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experimental part
p. 2529 - 2532
(2009/09/06)
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- Solvent-free oxidation of aliphatic alcohols with ceric ammonium nitrate-lithium bromide system
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Esters are formed during the solvent-free oxidation of primary aliphatic C5-C9 alcohols with Ce(NH4)2(NO 3)6-LiBr, whereas secondary octan-2-ol gives a mixture of isomeric 1-and 3-bromooctan-2-ones.
- Kapustina,Sokova,Gasanov,Nikishin
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p. 1501 - 1506
(2008/09/19)
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- Phenoxypropanolamine compounds
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Compounds of the formula (I): STR1 wherein R1 is hydrogen or fluoro and R2 is hydrogen or C1-6 alkyl and salts thereof are described as agents for the treatment of obesity and related conditions. Processes for their preparation and intermediates are described.
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- SYNTHESIS OF 4-IMIDAZOLIN-2-ONES
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The reaction of α-bromoketones with CO(NH2)2 and AcONH4 in aqueous acetic acid gave substituted 4-imidazolin-2-ones.
- Zav'yalov, S. I.,Sitkareva, I. V.,Ezhova, G. I.,Dorofeeva, O. V.,Zavozin, A. G.,Rumyantseva, E. E.
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p. 1297 - 1299
(2007/10/02)
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- A CONVENIENT SYNTHESIS OF α-BROMOKETONES FROM OLEFINS
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α-Bromoketones are prepared in good yields by the reaction of olefins with sodium bromite in aqueous acetic acid at room temperature.
- Kageyama, Toshifumi,Tobito, Yoshimichi,Katoh, Atsushi,Ueno, Yoshio,Okawara, Makoto
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p. 1481 - 1482
(2007/10/02)
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- ONE POT SYNTHESIS OF α-BROMO AND α-IODO KETONES FROM EPOXIDES
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α-bromo and α-iodo ketones are obtained in good yield and in one pot by reaction of terminal and disubstituted epoxides with trimthylsilyl halides and further oxidation (CrO3/H2SO4).
- Denis, J. N.,Krief, A.
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p. 1429 - 1430
(2007/10/02)
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- ORGANIC SYNTHESIS WITH SULPHONES - XVII. THE ANTI-MARKOWNIKOFF HALOSULPHONYLATION OF OLEFINS VIA AN IONIC PATHWAY, AND A NEW METHOD OF PREPARING BENZENESULPHONYL IODIDE
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Iodine and bromine in the presence of sodium benzenesulphinate react with olefins in acetone solution to give halosulphones resulting from an apparent steric direction of attack at the intermediate halonium ion.A straightforward preparation of benzenesulphonyl iodide from benzenesulphonyl chloride and sodium iodide is also described.
- Harwood, L. M.,Julia, M.,Thuillier, G. Le
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p. 2483 - 2487
(2007/10/02)
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