- Novel usage of 2-BTSO2CF2H for metal-free electrophilic difluoroalkanethiolation of indoles
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The electrophilic difluoromethylthiolation of indoles with 2-BTSO2CF2H is developed. In the presence of (EtO)2P(O)H and TMSCl, the reaction proceeded under mild conditions to give products in modest to high yields. This is a new application of 2-BTSO2CF2H for electrophilic difluoromethylthiolation.
- Bao, Kun,Hu, Jinbo,Sheng, Rong,Wang, Yuan,Wei, Jun
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- Ionic Reactivity of 2-Isocyanoaryl Thioethers: Access to 2-Halo and 2-Aminobenzothia/Selenazoles
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An ionic cascade insertion/cyclization reaction of thia-/selena-functionalized arylisocyanides has been successfully developed for the efficient and practical synthesis of 2-halobenzothiazole/benzoselenazole derivatives. This synthetic protocol, incorporating a halogen atom when forming the five-membered ring of benzothia/selenazoles, is different from the existing ones, where halogenation of the preformed benzothia/selenazole precursors happens. Additionally, a facile access to 2-aminobenzothiazoles is also achieved by the one-pot cascade reaction of 2-isocyanoaryl thioethers, iodine, and amines.
- Dong, Jinhuan,Hu, Junlin,Liu, Xiaoli,Sun, Shaoguang,Bao, Lan,Jia, Mengying,Xu, Xianxiu
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p. 2845 - 2852
(2022/02/23)
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- Deaminative chlorination of aminoheterocycles
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Selective modification of heteroatom-containing aromatic structures is in high demand as it permits rapid evaluation of molecular complexity in advanced intermediates. Inspired by the selectivity of deaminases in nature, herein we present a simple methodology that enables the NH2 groups in aminoheterocycles to be conceived as masked modification handles. With the aid of a simple pyrylium reagent and a cheap chloride source, C(sp2)?NH2 can be converted into C(sp2)?Cl bonds. The method is characterized by its wide functional group tolerance and substrate scope, allowing the modification of >20 different classes of heteroaromatic motifs (five- and six-membered heterocycles), bearing numerous sensitive motifs. The facile conversion of NH2 into Cl in a late-stage fashion enables practitioners to apply Sandmeyer- and Vilsmeier-type transforms without the burden of explosive and unsafe diazonium salts, stoichiometric transition metals or highly oxidizing and unselective chlorinating agents. [Figure not available: see fulltext.]
- Cornella, Josep,Faber, Teresa,Gómez-Palomino, Alejandro,Ghiazza, Clément
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- A 2 - chlorobenzene and method of synthesizing
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The invention discloses a 2 - chlorobenzene and method of synthesizing, by the benzothiazole by chlorine direct chlorination synthesis 2 - chlorobenzene and thiazole; specifically comprises the following steps: the metering the inert solvent with the benzothiazole, catalyst is added with the cooler and the tail gas absorption device, can be carried out with stirring and chlorine is introduced into the tube reactor, heating, started to access the metering of chlorine reaction; after the reaction, then after treatment to obtain the 2 - chlorobenzene and thiazole. The invention has the easy availability of raw materials, the process is simple, the operation is simple, mild reaction conditions, the solvent can be recycled, high yield, high quality, and is suitable for industrial production and the like; reduce the production cost, reduce the pollution of the environment.
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Paragraph 0017-0024
(2019/03/28)
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- Direct Transformation of Arylamines to Aryl Halides via Sodium Nitrite and N-Halosuccinimide
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A one-pot universal approach for transforming arylamines to aryl halides via reaction with sodium nitrite (NaNO2) and N-halosuccinimide (NXS) in DMF at room temperature under metal- and acid-free condition is described. This new protocol that is complementary to the Sandmeyer reaction, is suggested to involve the in situ generation of nitryl halide induce nitrosylation of aryl amine to form the diazo intermediate which is halogenated to furnish the aryl halide.
- Mukhopadhyay, Sushobhan,Batra, Sanjay
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supporting information
p. 14622 - 14626
(2018/09/21)
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- T -BuONa-mediated direct C-H halogenation of electron-deficient (hetero)arenes
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An efficient halogenation of electron-deficient (hetero)arenes is described. The reaction utilizes common t-BuONa as a catalyst (for iodination) or a promoter (for bromination and chlorination), and perfluorobutyl iodide, CBr4 or CCl4 as the readily-available halogenating agents, respectively. The protocol features broad scope, high efficiency, mild conditions and gram scalability. An ionic pathway involving halogen bond formation and halophilic attack is proposed. The utility of the resulting iodinated heteroarenes is demonstrated in visible light-mediated Caryl-Caryl cross-coupling reaction.
- Liu, Xia,Zhao, Xin,Liang, Fushun,Ren, Baoyi
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supporting information
p. 886 - 890
(2018/02/19)
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- Synthesis and biological evaluation of heteroarylnonanenitriles as potential antitrypanosomal agents: Serendipitous discovery of novel anticholinesterase hits
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We have recently developed three antitrypanosomal leads that feature a unit of huprine or (6-chloro-)tacrine linked to a 8-cyanooctyl side chain, which, unfortunately, exhibit very potent (low nanomolar) acetylcholinesterase (AChE) inhibitory activity, which might lead to unwanted cholinergic side-effects. Because huprine and tacrine moieties impart high acetylcholinesterasic potency, we have explored their replacement by alternative heteroaromatic systems (thiazolylbenzamido, quinoxalinecarboxamido, benzimidazolecarboxamido, and benzothiazolylamino moieties), while retaining the 8- cyanooctyl side chain. These structural modifications led to the desired drop in AChE inhibitory activity (low micromolar), albeit at the expense of the antitrypanosomal potency. However, despite the lower AChE inhibitory activity of the novel compounds compared to that of the initial leads, their potency is comparable to that of some AChE inhibitors currently approved for Alzheimer’s disease (AD) treatment. They are brain permeable and less lipophilic than the leads, thereby emerging as interesting novel hits for future AChE inhibitor-based AD drug discovery programs.
- Artigas, Albert,Sola, Irene,Taylor, Martin C.,Clos, M. Victòria,Pérez, Belén,Kelly, John M.,Mu?oz-Torrero, Diego
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p. 455 - 461
(2018/05/22)
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- Water-Promoted Chlorination of 2-Mercaptobenzothiazoles
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Substituted benzothiazoles play an important role in medicinal chemistry due to their pharmacological properties. Their 2-substituted derivatives are often prepared from 2-chlorobenzothiazoles, which in turn can be synthesized from the 2-mercapto precursor using sulfuryl chloride. In practice, this seemingly straightforward and widely used reaction can be impeded by poor reproducibility and low reaction yields. In this communication, we report that the simple addition of water to the reaction leads to remarkable improvements in reaction efficiency. We attribute this effect to the formation of acid through partial hydrolysis of sulfuryl chloride. This hypothesis is supported by the observation that improved yields were also obtained in the presence of some anhydrous acidic additives. The simple combination of sulfuryl chloride and water reproducibly provides excellent yields for a range of chlorinated products.
- Wimmer, Laurin,Parmentier, Michael,Riss, Bernard,Kapferer, Tobias,Ye, Chao,Li, Lei,Kim, Hongyong,Li, Jialiang
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p. 2027 - 2032
(2018/04/16)
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- Efficient transposition of the sandmeyer reaction from batch to continuous process
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The transposition of Sandmeyer chlorination from a batch to a safe continuous-flow process was investigated. Our initial approach was to develop a cascade method using flow chemistry which involved the generation of a diazonium salt and its quenching with copper chloride. To achieve this safe continuous process diazotation, a chemometric approach (Simplex method) was used and extrapolated to establish a fully continuous-flow method. The reaction scope was also examined via the synthesis of several (het)aryl chlorides. Validation and scale-up of the process were also performed. A higher productivity was obtained with increased safety.
- D'Attoma, Joseph,Camara, Titi,Brun, Pierre Louis,Robin, Yves,Bostyn, Stéphane,Buron, Frédéric,Routier, Sylvain
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- Method for preparing halogenated (hetero) aromatic hydrocarbons
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The invention relates to a method for preparing halogenated (hetero) aromatic hydrocarbons. The halogenated (hetero) aromatic hydrocarbons are prepared from cheap and easily available perfluorobutyl iodide, carbon tetrabromide and carbon tetrachloride as iodinated, brominated and chlorinated reagents respectively under the action of alkali catalysis (promotion). The method comprises the following steps: firstly, (hetero) aromatic hydrocarbons, a halogenated reagent and an inorganic base are placed in an organic solvent, stirred at room temperature and monitored with TLC until a substrate disappears, and the reaction is stopped; then, a reaction mixed solution is poured into water and extracted, an organic phase is dried, and the organic solvent is removed under reduced pressure; finally, silica-gel column chromatography is performed on a crude product, and a product is obtained. Purification can also be performed by recrystallization. The method has the advantages that the synthetic route is wide in substrate range, raw materials and reagents are cheap and easily available, operation is simple, conditions are mild, yield is high, energy consumption is reduced, the reaction route is safe, gram-grade preparation can be performed and the like.
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Paragraph 0063; 0064
(2018/03/24)
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- 2 - chlorobenzene and method of synthesizing (by machine translation)
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The invention relates to the field of chemical industry, discloses a 2 - chlorobenzene and method of synthesizing, comprising the following steps: (1) will be 2 - mercaptobenzothiazole dispersed in water to form a paste 2 - mercapto benzothiazole; (2) to the paste 2 - mercaptobenzothiazole added in the mass fraction is 30% hydrochloric acid mixed so as to obtain a mixture; (3) the mixture is heated to 35 - 45 °C after, dropping the oxidizing agent, thermal insulation reaction to the detection to the system of 2 - mercaptobenzothiazole content of less than 0.2% stop the instillment states oxidizing agent; (4) pulling out the upper layered oily liquid is 2 - chlorobenzene and thiazole crude product. Compared with the prior art, the method reduces the waste gas output, reducing the pollution of the environment, and does not require the use of dangerous raw materials, reduces the risk of in the production process, the production cost is reduced. (by machine translation)
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Paragraph 0019; 0014; 0015; 0016; 0017; 0018
(2017/09/13)
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- Hydroxylamine as an oxygen nucleophile: Substitution of sulfonamide by a hydroxyl group in benzothiazole-2-sulfonamides
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Benzothiazole-2-sulfonamides react with an excess of hydroxylamine in aqueous solutions to form 2-hydroxybenzothiazole, sulfur dioxide, and the corresponding amine. Mechanistic studies that employ a combination of structure-reactivity relationships, oxygen labeling experiments, and (in)direct detection of intermediates and products reveal that the reaction proceeds via oxygen attack, and that oxygen incorporated in the 2-hydroxybenzothiazole product derives from hydroxylamine. The reaction, which is performed under mild conditions, can be used as a deprotection method for cleavage of benzothiazole-2-sulfonyl-protected amino acids.
- Kamps, Jos J. A. G.,Belle, Roman,Mecinovi?, Jasmin
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supporting information
p. 1103 - 1108
(2013/03/28)
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- Preparation, antibacterial evaluation and preliminary structure-activity relationship (SAR) study of benzothiazol- and benzoxazol-2-amine derivatives
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In this study, a novel benzothiazol- and benzooxazol-2-amine scaffold with antibacterial activity was designed and synthesized. Preliminary structure-activity relationship analysis displayed that compound 8t with a 5,6-difluorosubstituted benzothiazole was found to be a potent inhibitor of Gram-positive pathogens, and exhibited some potential against drug-resistant bacteria and without cytotoxicity in therapeutic concentrations. In addition, molecular docking studies indicated that Staphylococcus aureus methionyl-tRNA synthetase might be the possible target of these compounds. Taken together, the present study provides an effective entry to the synthesis of a good lead for subsequent optimization and a new small molecule candidate drug for antibacterial therapeutics.
- Ouyang, Liang,Huang, Yuhui,Zhao, Yuwei,He, Gu,Xie, Yongmei,Liu, Jie,He, Jun,Liu, Bo,Wei, Yuquan
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p. 3044 - 3049
(2012/06/04)
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- Synthesis, antioxidant properties and radioprotective effects of new benzothiazoles and thiadiazoles
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In this work, we report the synthesis and characterization of new compounds derived from benzothiazoles and thiadiazoles. We observed that structural modifications on these skeletons affected the antioxidant activity. Thiol and aminothiol compounds derived from thiadiazoles and benzothiazoles showed an interesting antioxidant property. The radioprotective activity has also been evaluated in mice. Some of these compounds could be good radioprotectors.
- Cressier, Damien,Prouillac, Caroline,Hernandez, Pierre,Amourette, Christine,Diserbo, Michel,Lion, Claude,Rima, Ghassoub
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experimental part
p. 5275 - 5284
(2009/12/04)
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- A simple base-mediated halogenation of acidic sp2 C-H bonds under noncryogenic conditions
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(Chemical Equation Presented) A new method has been developed for in situ halogenation of acidic sp2 carbon-hydrogen bonds in heterocycles and electron-deficient arenes. Either selective monohalogenation or one-step exhaustive polyhalogenation is possible for substrates possessing several C-H bonds that are flanked by electron-withdrawing groups. For the most acidic arenes, such as pentafluorobenzene, K3PO4 base can be employed instead of BuLi for metalation/halogenation sequences.
- Do, Hien-Quang,Daugulis, Olafs
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supporting information; experimental part
p. 421 - 423
(2009/07/04)
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- In situ generation and trapping of aryllithium and arylpotassium species by halogen, sulfur, and carbon electrophiles
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(Chemical Equation Presented) A general method has been developed for in situ trapping of arylmetal intermediates by halogen, sulfur, ketone, and aldehyde electrophiles affording the functionalization of the most acidic position in arene. Pentafluorobenzene, benzothiazole, and benzoxazole can be functionalized by using K3PO4 base. For less acidic arenes, tBuOLi base is required. Arenes with DMSO pKa values of 35 or less are reactive. 2009 American Chemical Society.
- Popov, Ilya,Do, Hien-Quang,Daugulis, Olafs
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supporting information; experimental part
p. 8309 - 8313
(2010/01/16)
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- Ferulic acid and benzothiazole dimer derivatives with high binding affinity to β-amyloid fibrils
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New ferulic acid and benzothiazole dimer derivatives were synthesized and evaluated by in vitro competition assay using [125I]TZDM for their specific binding affinities to Aβ fibrils. In particular, 4a showed the most excellent binding affinity (Ki = 0.53 nM), compared to PIB (Ki = 0.77 nM), for benzothiazole binding sites of Aβ1-42 fibrils. This result suggests a possibility of a potential AD diagnostic probe for detection of Aβ fibrils.
- Byeon, Seong Rim,Jin, Yun Jung,Lim, Soo Jeong,Lee, Ji Hoon,Yoo, Kyung Ho,Shin, Kye Jung,Oh, Seung Jun,Kim, Dong Jin
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p. 4022 - 4025
(2008/02/07)
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- Convenient one-pot synthesis of sulfonamides from thiols using trichloroisocyanuric acid
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A convenient synthesis of sulfonamides from thiols is described. In situ preparation of sulfonyl chlorides from thiols is accomplished by oxidation with trichloroisocyanuric acid (TCCA), benzyltrimethylammonium chloride and water (2.5 equiv). The sulfonyl chlorides are then further allowed to react with excess amine in the same reaction vessel. Triethylamine can be optionally added as acid scavenger. Copyright Taylor & Francis Group, LLC.
- Bonk, Jason D.,Amos, David T.,Olson, Sarah J.
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p. 2039 - 2050
(2008/02/04)
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- A Novel Method for the Synthesis of 2(3H)-Benzimidazolones, 2(3H)-Benzoxazolone, and 2(3H)-Benzothiazolone via in Situ Generated Ortho Substituted Benzoic Acid Azides: Application of Ammonium Azide and Vilsmeier Complex for Acid Azide Generation
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An easy and generalized route to 2(3H)-benzimidazolones, 2(3H)-benzoxazolone and 2(3H)-benzothiazolone is attempted. A novel one-pot method for the in situ generation and cyclisation of ortho substituted benzoic acid azides is reported via the application of ammonium azide and Vilsmeier complex.
- Sridhar, Radhakrishnan,Perumal, Paramasivan T.
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p. 735 - 742
(2007/10/03)
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- Tetrahalogenomethanes: Simple reagents for the synthesis of monohalogenated and mixed dihalogenated aromatic heterocycles via metal-halogen exchange from lithium compounds
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Tetrabromo- or tetrachloromethane and 2-lithio derivatives of aromatic heterocycles rapidly produce the corresponding 2-bromo or 2-chloro derivatives in high yields through a metal-halogen exchange mechanism. This kind of reaction was also used to obtain, in good yields, 5-bromo-2-chlorothiazole and 5-bromo-2-chloro-N-methylimidazole.
- Boga, Carla,Del Vecchio, Erminia,Forlani, Luciano,Todesco, Paolo Edgardo
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p. 233 - 236
(2007/10/03)
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- A new synthesis of chloroheterocycles via metal-halogen exchange between trichloroacetyl derivatives and heteroaromatic lithium and Grignard reagents
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The reaction between 2-lithio derivatives of aromatic azaheterocycles and trichlorocetyl derivatives rapidly produces the corresponding 2-chloro derivatives in high yields through a metal-halogen exchange mechanism. The use of ethyl trichloroacetate can give better results with respect to those obtained with trichloroacetyl chloride, which probably involves dichloroketene formation. The reaction with Grignard reagents is more complex: in fact, 2-benzothiazolylmagnesium chloride with ethyl trichloroacetate or trichloroacetyl chloride gives 2-chlorobenzothiazole together with considerable amounts of ethyl 1,3-benzothiazole-2-carboxylate or 2-benzothiazolyl dichloromethyl ketone, respectively.
- Boga, Carla,Del Vecchio, Erminia,Forlani, Luciano,Milanesi, Lilia,Edgardo Todesco, Paolo
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p. 155 - 159
(2007/10/03)
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- Preparation of 1,4-Dienes from 2-(2-Hydroxyalkylseleno)benzothiazoles by the Reaction Involving Se -> O Azaaromatic Ring Rearrangement
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The reactions of 2-(2-oxoalkylseleno)benzothiazoles with allylic Grignard reagents in the presence of BF3*OEt2 gave the corresponding 2-benzothiazoles which, on treatment with Ph3P and NaH, afforded 1,4-dienes in good to excellent yields.
- Shibata, Koichi,Mitsunobu, Oyo
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p. 3163 - 3173
(2007/10/02)
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- Piperdine and piperazine derivatives, and antihistaminic pharmaceutical compositions containing the same
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Disclosed is a compound represented by Formula (I): STR1 wherein Ar1, Ar2, n, A, B and Z are as defined in claims. Disclosed are also a process for preparing the compound and pharmaceutical compositions containing the compound. The compound has an antihistamic and antiallergic effect.
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