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Two new propeller-shaped benzothiazole-enamide boron difluoride complexes exhibiting piezochromic luminescence upon mechanical grinding or hydrostatic compression were prepared. The two analogues displayed the red shift in luminescence under high pressure, while compound 2 with ICT effects showed a more sensitive piezochromic response at low pressure (1.5 GPa). The different piezochromic luminescence behaviors of these compounds were investigated. This journal is

A novel S8-mediated approach to benzothiazoles/benzoselenazoles from bis(2-aminophenyl) disulfides/diselenides and phenylacetylenes or styrenes has been developed. 2-(Arylmethyl)-1,3-benzoselenazoles were comprehensively synthesized for the first time. The reactions proceeded in moderate to excellent yields, and with a gramscale application.

A halogen-bond promoted ring-opening methylation of benzothiazoles has been developed using dimethyl sulphite as a methylating reagent in the presence of a base. This approach represents a simple and efficient synthesis ofN-methyl-N-(o-methylthio)phenyl amides, and features direct construction of both N-Me and S-Me bonds in a one-pot reaction through the decomposition of easily prepared benzothiazoles.

An efficacious and mild KOtBu-promoted intramolecular C-S cross-coupling of ortho-iodothioanilides in conjunction with a catalytic quantity of phenanthroline as an additive has been described for the convenient synthesis of 2-substituted benzothiazoles. The methodology is suitable for attaining a wide variety of 2-alkyl- and 2-aryl-substituted benzothiazoles. Single-crystal XRD, DFT calculations, NMR, and UV studies suggest that halogen bonds between the units of ortho-iodothioanilides may assist in the electron transfer process.

An efficient method to assemble diverse benzoxazoles/benzothiazoles in good yields was developed via oxidative cyclization with 2-aminothiophenols or 2-iodoanilines as raw materials. In this protocol, elemental sulfur was used as the effective oxidant and C atoms on the C=C double bond were introduced as a one-carbon donator.

An efficient one-pot method to access 2-acylbenzothiazoles via AlCl3-mediated cyclization reaction and I2-promoted sequential oxidation reaction of 2-aminobenzenethiols with arylacetonitriles was developed. This reaction proceeds smoothly with a wide range of arylacetonitriles containing different functional groups to give the corresponding products in moderate to good yields under mild conditions. Moreover, this reaction was conveniently conducted on a gram scale, and the yield is still up to 68%.

An efficient Selectfluor-oxidative protocol was developed for the direct C2-arylacylation of 2H-benzothiazoles via the radical reaction of 2H-benzothiazoles with methyl arenes. Selectfluor can effectively promote the oxidative cross-coupling without an ex

The synthesis of 2-substituted benzothiazoles has been described using ZnO-nanoparticles as a catalyst. The condensation of 2-aminothiophenol and aryl/alkyl nitriles resulted in the formation of various 2-substituted benzothiazoles under solvent-free reaction conditions. The library of 2-substituted benzothiazoles has been synthesized in good to excellent yield. The reaction has shown a wide range of functional group compatibility for both varyingly substituted 2-aminothiophenols and nitriles. The protocol has many advantages such as faster reaction rate, mild reaction conditions, various functional group compatibility, excellent yield, solvent-free reaction conditions, easy recovery of materials, and excellent catalyst recyclability, among others. The various advantages of this protocol make it a more feasible, economical, and environmentally benign process.

Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the synthesis of 2-substituted benzothiazoles. The corresponding benzothiazoles were obtained using a condensation reaction of 2-aminothiophenol with various aldehydes under ultrasound irradiation at room temperature. Various functional groups on the 2-aminothiophenol as well as on the aldehydes were tolerated to provide 2-substituted benzothiazoles derivatives in excellent yields. The faster reaction rate, solvent-free or mild reaction conditions, wide functional group compatibility, excellent yields, easy work-up procedure, and excellent catalyst recyclability are the advantages of this protocol. These advantages make this process more practicable, cost-effective, and environmentally benign.

An efficient and green method, combining enzymatic and visible-light catalysis for synthesis of the widely applicable 2-substituted benzothiazoles, has been developed. This method features a relay catalysis protocol consisting of biocatalytic promiscuity

The invention discloses a photocatalytic synthesis method of a C2 substituted 2H-benzothiazole benzylated derivative. The photocatalytic synthesis method comprises the following steps of: mixing 2H-benzothiazole with substituted methyl benzene; adding an oxidizing agent Selectfluor, an additive trifluoroacetic acid and a solvent acetonitrile, carrying out a normal temperature stirring reaction under the protection of nitrogen and the irradiation of an LED blue light lamp, carrying out TLC monitoring until the reaction is finished, and carrying out separation and purification on the reaction liquid to obtain the C2 substituted 2H-benzothiazole benzylated derivative. The new method for synthesizing the C2 substituted 2H-benzothiazole benzylated derivative through visible light induction by taking Selectfluor as an oxidizing agent, trifluoroacetic acid as an additive and acetonitrile as a solvent is high in atom economy, simple in catalytic system, good in product yield, wide in substraterange and suitable for popularization and application.

The invention relates to a method for synthesizing 2-substituted benzothiazole by a one-pot method. The preparation method comprises the following specific steps: dissolving a 2-Iodoaniline compound,a styrene compound, elemental sulfur, an alkaline medium

An efficient TBHP/KI-promoted annulation of anilines with ethers and elemental sulfur has been developed through the selective C-O bond cleavage of ethers under transition-metal-free conditions. A wide range of 2-aryl-, 2-heteroaryl-, and 2-alkyl-substituted benzothiazoles were easily prepared with satisfactory yields and good functional group compatibility.

An efficient and mild protocol has been developed for the synthesis of 2-substituted benzothiazole under solvent- and metal-free conditions using CBr4 as the catalyst. This process involves the activation of a thioamide through halogen bond formation between the sulphur atom of the thioamide and bromine atom of the CBr4 molecule. The presence of halogen-bonding interaction between N-methylthioamides and tetrabromomethane has been demonstrated with several control experiments, spectroscopic analysis and density functional theory (DFT). This methodology has a wide substrate scope for the synthesis of both 2-alkyl and 2-aryl substituted benzothiazoles.

A novel strategy of cascade radical C(sp2/sp3)-S bond cleavage and group-transfer cyclization is disclosed. Triggered by alkyl radicals, varieties of 2-isocyanoaryl thioethers containing aliphatic, aryl, and heteroaromatic groups can be cleaved and precisely reinstalled to give benzothiazole derivatives. Mechanistic studies reveal that the cascade reaction undertakes an intermolecular pathway, and the inner radical sources (R radicals) exhibit high priority over those of methyl radical origin from di-tert-butyl peroxide.

CDI combined with CH3SO3H was found to be highly effective for the cyclization of 2-aminothiophenol derivatives with carboxylic acids under MW condition. Fourteen benzothiazole derivatives were synthesized in good yield and their structures were characterized by1H-NMR,13C-NMR, IR and mass spectrometry. This simple, rapid synthetic method is believed to provide a useful process for the synthesis of 2-substituted benzothiazole compounds.

The enantioselective dearomative [3 + 2] cycloaddition reaction of benzazoles with aminocyclopropanes has been successfully developed. In the presence of a copper complex, derived from Cu(OTf)2 and bisoxazoline, a series of hydropyrrolo-benzazole derivatives containing quaternary stereogenic centers were obtained in high yields with excellent enantioselectivity. This method could also provide 2-amino cyclopropanes with high enantiomeric purity by an efficient kinetic resolution. In addition, products could be transformed to pyrrolo-benzothiazines and 1,5-benzothiazepines. Chiral compounds are of great significance in many areas given that two corresponding enantiomers could have completely different properties in chiral environments. Therefore, technologies used to produce chiral compounds in their enantiopure form are particularly attractive and highly desirable. Catalytic asymmetric dearomatization reactions have become efficient methods for the construction of chiral fused- or spiro-heterocycles from simple aromatics. Polyheterocyclic structures containing a hydropyrrolo-azole motif are found extensively in natural products and biologically active compounds. Therefore, efficient methods for constructing complex chiral hydropyrrolo-azole compounds will benefit the lead identification in drug discovery. Herein, we report the highly enantioselective construction of hydropyrrolo-benzazoles via copper-catalyzed dearomative [3 + 2] cycloaddition of benzazoles with donor-acceptor aminocyclopropanes. Heterocycles are a very important class of compounds that exist extensively as structural cores in natural products and biologically active molecules. Catalytic asymmetric dearomatization (CADA) is an efficient strategy for the construction of chiral fused- or spiro-heterocycles from simple planar aromatic compounds. Herein, we report the development of enantioselective dearomative [3 + 2] cycloaddition reactions of benzazoles with aminocyclopropanes via kinetic resolution. In the presence of a copper complex, derived from Cu(OTf)2 and bisoxazoline, a series of hydropyrrolo-benzazole derivatives containing quaternary stereogenic centers were obtained in high yields (up to 99%) with excellent enantioselectivity (up to 99% enantiomeric excess [ee]). With the same catalytic system, 2-amino cyclopropane-1,1-dicarboxylates with a high enantiomeric purity (up to 98% ee) were also obtained by an efficient kinetic resolution (s values of up to 95). In addition, the utility of this method was showcased by the facile transformation of products into several important heterocyclic frameworks, including pyrrolo-benzothiazine and 1,5-benzothiazepine.

A visible-light-induced radical cascade cyclization of 2-isocyanoaryl thioethers for the synthesis of 2-CF2/CF3-containing benzothiazoles has been developed. Sodium sulfite can participate in the photocatalytic cycle as a reductant that efficiently transforms Ir4+ into Ir3+ to promote the fluoroalkylation under mild reaction conditions.

The efficient synthesis of 2-substituted thiazoles and benzothiazoles has been accomplished employing readily available cysteine esters and 2-aminobenzenethiols as N and S sources. The reaction proceeds under an I2/TBHP system and involves a on

A three-component synthesis of 2-substituted benzothiazoles from aryl amines, elemental sulfur and styrenes or aryl acetylenes in 1-methylpyrrolidin-2-one (NMP) is described. Two C?S and one C?N bonds were selectively formed in one-pot under metal-free conditions. (Figure presented.).

Selective construction of 2-substituted benzothiazoles from o-iodoaniline derivatives S8 and N-tosylhydrazone via a copper-promoted [3 + 1 + 1]-type cyclization reaction has been realized. In the protocol, the carbon atom on N-tosylhydrazone could be regulated to construct benzothiazole by changing the reaction system. Furthermore, the transformation has achieved the construction of multiple carbon-heteroatom bonds.

A concise and efficient protocol to assemble diverse benzothiazole derivatives in high yields was provided via copper catalyzed tandem cyclization with o-haloanilines, elemental sulfur and terminal alkynes as raw materials. In this protocol, C atoms on the CC triple bond were controllably involved in the construction of the benzothiazole framework and multiple carbon-heteroatom bonds through divergent routes.

A catalyst- and supporting electrolyte-free method for electrochemical dehydrogenative C?S bond formation in continuous flow has been developed. A broad range of N-arylthioamides have been converted to the corresponding benzothiazoles in good to excellent yields and with high current efficiencies. This transformation is achieved using only electricity and laboratory grade solvent, avoiding degassing or the use of inert atmosphere. This work highlights three advantages of electrochemistry in flow, which is (i) a supporting electrolyte-free reaction, (ii) an easy scale-up of the reaction without the need for a larger reactor and, (iii) the important and effective impact of having a good mixing of the reaction mixture, which can be achieved effectively with the use of flow systems. This clearly improves the reported methods for the synthesis of benzothiazoles.

In this report, we introduced Graphene oxide-iron oxide (GO-Fe3O4) nanocomposites as a heterogeneous catalyst for arylation/alkylation of benzothiazoles with aldehydes and benzylic alcohols in the presence of diisopropyl azodicarboxylate (DIAD) as an oxidant which exclusively produced 2-aryl (alkyl)-1H–benzothizoles in moderate to excellent yields. The absence of precious metals and toxic solvent, easy product isolation, and recyclability of the GO-Fe3O4 with no loss of activity are notable advantages of this method.

Metal-free halogen(I) catalysts were used for the selective oxidation of aryl(heteroaryl)methanes [C(sp3)?H] to ketones [C(sp2)=O] or esters [C(sp3)?O]. The synthesis of ketones was performed with a catalytic amount of NBS in DMSO solvent. Experimental studies and density functional theory (DFT) calculations supported the formation of halogen bonding (XB) between the heteroarene and N-bromosuccinimide, which enabled imine–enamine tautomerism of the substrates. No additional activator was required for this crucial step. Isotope-labeling and other supporting experiments suggested that a Kornblum-type oxidation with DMSO and aerobic oxygenation with molecular oxygen took place simultaneously. A background XB-assisted electron transfer between the heteroarenes and halogen(I) catalysts was responsible for the formation of heterobenzylic radicals and, thus, the aerobic oxygenation. For selective acyloxylation (ester formation), a catalytic amount of iodine was employed with tert-butyl hydroperoxide in aliphatic carboxylic acid solvent. Several control reactions, spectroscopic studies, and Time-Dependent Density Functional Theory (TD–DFT) calculations established the presence of acetyl hypoiodite as an active halogen(I) species in the acetoxylation process. With the help of a selectivity study, for the first time we report that the strength of the XB interaction and the frontier orbital mixing between the substrates and acyl hypoiodites determined the extent of the background electron-transfer process and, thus, the selectivity of the reaction.

An oxidative cyclization of 2-aminothiophenols and arylacetylenes or styrenes for the synthesis of 2-alkylbenzothiazoles and 2-acylbenzothiazoles has been developed. Elemental sulfur was used as the effective oxidant to give the corresponding product in g

2-Substituted benzothiazoles were synthesized through condensation of bis(2-aminophenyl) disulfides with arylaldehydes catalyzed by inexpensive NaSH in PEG-300 and assisted by low energy microwave irradiation(25?W). Various 2-substitutedbenzothiazoles were obtained in moderate to high yields after simple post-reaction processing including adding distilled water, filtrating, and drying. Moreover, it was found that the S-S bond of the disulfide was reduced by NaSH and also by the intermediate benzothiazoline.

A visible-light-promoted synthesis of benzothiazoles from 2-aminothiophenols and aldehydes has been developed. A wide range of aromatic, heteroaromatic and aliphatic aldehydes were successfully applied. The benzothiazole products were prepared in good yields. The reaction was carried out in the absence of transition-metal catalysts and extra additives. A radical reaction pathway was proposed.

An easy and practical method has been developed for the synthesis of 2-benzylbenzoxazoles and 2-benzylbenzothiazoles using sulfur mediated decarboxylative coupling of cinnamic acids with 2-hydroxyanilines and 2-mercaptoanilines respectively under metal- and solvent-free conditions. However, the reaction of 2-aminoanilines with cinnamic acids leads to the formation of 2-arylquinoxalines under the same set of reaction conditions. The transformation is versatile and compatible with a number of functional groups.

The condensation of 2-aminothiophenol with aliphatic aldehydes in the presence of 4? molecular sieves, followed by oxidation with silica gel supported pyridinium chlorochromate offers a simple and efficient route to 2-alkylbenzothiazoles.

An efficient chemical method for the synthesis of benzimidazoles, benzothiazoles, and benzoxazoles has been developed through the condensation of various aldehydes with o-phenylenediamine, o-aminothiophenol, and o-aminophenol using graphene oxide (GO) as an oxidant in water. These benzazoles are also prepared through a one-pot oxidation/condensation tandem process by reacting alcohols with 2-amino-(thio)phenol/aniline in the presence of GO in poly(ethylene glycol) as a safe media. Moreover, this carbonaceous material could be readily separated using a simple filtration.

A metal-free process for the synthesis of benzothiazoles via PCl3-promoted cleavage/acylation/ cyclization of disulfides and carboxylic acids has been developed. In addition to acting as the acylating reagent which converted carboxylic acids into acyl chlorides, PCl3 also converted disulfides to thiols, which promoted disulfides of 2-aminobenzenethiol reacted with carboxylic acid to produce benzothiazoles. The developed method is applicable to a wide range of carboxylic acids containing different functional groups.

A new and efficient method for preparation of benzimidazoles, benzoxazoles, and benzothiazoles from reactions of different carboxylic acids with o-phenylenediamine, o-aminophenol, and o-aminothiophenol in the presence of triphenylphosphine/trichloroisocyanuric acid system is presented. The desired products have been characterised on the basis of spectral (infrared, NMR, mass spectrometry) data, and the mechanism of their formation is proposed. The remarkable advantages are the inexpensive and readily available reagent, simple procedure, mild conditions, and good-to-excellent yields.

A facile synthetic method for benzothiazoles and benzoxazoles comprising the reaction of corresponding 2-aminothiophenol and 2-aminophenol with various substituted aromatic carboxylic acids using Samarium(III) triflate as a catalyst has been described. The advantages of the method are short reaction times and aqueous reaction media and easy work-up. The catalysts can be recovered for the subsequent reactions and reused without any appreciable loss of efficiency.

New keto-enol tautomeric benzoxazolyl and benzthiazolyl-1,2-diaryl β-ketoiminate based organoboron complexes have been synthesised and their fluorescence properties investigated. Boron complexes are widely known for their fluorescent properties, here we have synthesized organoboron complexes that show bright fluorescence in solid state and hardly any fluoresce in solution. These compounds exhibit aggregation induced emission (AIE) activity. Density functional theory (DFT) was employed for geometry optimisation and molecular orbital distribution computations in the ground state of the molecules. Electrochemical study demonstrates that these molecules possess high electron affinities as compared to the current electroluminescent materials like tris(8-hydroxyquinoli- nato)-aluminium (Alq3) and BODIPY, indicating the prospects of these boron complexes as an cient emitters in the optoelectronics.

A compound represented by the following formula (I): wherein in formula (I), R1 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, a carbamoyl group, a sulfamoyl group, a sulfo

The magnetic nanoparticles-supported tungstosilicic acid (TSAMNP) was found to be a highly efficient solid acid for the synthesis of benzoazoles in water. TSAMNP catalyst was achieved by the immobilization of tungstosilicic acid [H4(W12SiO40)] species on the silica core-shell magnetic nanoparticles (Fe3O4@SiO2). A variety of aldehydes were successfully condensed with 1,2-diaminobenzene, 2-aminophenol and 2-aminothiophenol in water as a green solvent to synthesize benzoazoles in good-to-excellent yields. TSAMNP catalyst was easily separated from the reaction mixture and reused several times without any loss of efficiency.

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An efficient copper-catalyzed approach to benzo[b]thiophene and benzothiazole derivatives using thiocarboxylic acids as a sulfur source has been developed. In the presence of CuI and 1,10-phen, and n-Pr3N as the base, (2-iodobenzyl)triphenylphosphonium bromide and (2-iodophenylimino) triphenylphosphorane reacted smoothly with thiocarboxylic acids to give benzo[b]thiophene and benzothiazole derivatives in good yields via sequential Ullmann-type C-S bond coupling and Wittig condensation.

An efficient and convenient method was developed for the formation of 2-substituted benzothiazoles via a copper-catalyzed condensation of 2-aminobenzenethiols with nitriles. The developed method is applicable to a wide range of nitriles containing different functional groups furnishing excellent yields of the corresponding products.

A series of substituted benzimidazoles, benzothiazoles, and benzoxazoles was synthesized by combining 1,2-phenylenediamine, 2-aminothiophenol, or 2-aminophenol with aryl, heteroaryl, aliphatic, α,β-unsaturated aldehydes in the presence of nano ceria (CeO2) as an efficient heterogeneous catalyst.

2-Benzyl benzothiazoles and benzimidazoles are easily oxidized under air and basic conditions to give the corresponding ketones in good yields. The use of palladium acetate as a catalyst has little effect and even gives, in some cases, much lower yields.

A novel remarkably simple solvent-free and catalyst-free synthesis of benzazoles from alkylamines and o-hydroxy/amino/mercaptan anilines using elemental sulfur as traceless oxidizing agent has been developed.

A novel metal-free iodine-mediated intramolecular oxidative cyclization protocol is presented, which allows for the preparation of various 2-substituted benzothiazoles. Georg Thieme Verlag Stuttgart · New York.

Iron was used as the catalyst for the direct C-H functionalization/C-S bond formation under mild conditions. Various substrates could afford benzothiazoles in moderate to excellent yields. Preliminary mechanistic studies revealed that pyridine played a crucial role for the high yields and selectivities.

O-Benzenedisulfonimide has been used to efficiently catalyse the reaction between 2-aminothiophenol, 2-aminophenol, o-phenylenediamine and various ortho esters (28 examples; average yield 90%) or aldehydes (17 examples; average yield 72%) giving the corresponding benzofused azoles in excellent yields. Reaction conditions were very simple. In addition, other carboxylic acid derivatives have been tested and gave good results. The catalyst was easily recovered and reused. ARKAT-USA, Inc.

A facile and inexpensive method for the synthesis of 2-substituted benzothiazoles has been developed by Na2S2O 4-mediated cyclocondensations of 2,2′-disulfanediyldianilines with aldehydes. In the presence of Na2S2O4 and 4 A molecular sieves, a variety of 2-substituted benzothiazoles were obtained from the reaction of 2,2′-disulfanediyldianilines with aldehydes in moderate to high yields. Copyright

A novel method for the synthesis of heteroaryl ketones through one-pot tandem reaction of 1,1-dibromoethenes with 2-amino(thio)phenols promoted by TBAF·3H2O and RuCl3(5%)/air was developed. This novel method includes several reactions in one-pot and utilizes economical yet efficient reagents to generate synthetically and biologically interesting heteroaryl ketones under mild conditions with good efficiency.

A novel methodology for the synthesis of 2-benzoylbenzothiazoles and 2-benzylbenzothiazoles through FeCl3·6H2O catalyzed, air oxidized tandem process from commercially available 2-aminothiophenols and phenylacetaldehydes by using an

An efficient, economical, and convenient method was developed for the preparation of 2-substituted (N, O, C) benzothiazoles from N′-substituted- N-(2-halophenyl)thioureas, O′-substituted-N-(2-halophenyl) carbamothioates, or N-(2-halophenyl) thioamides via a base-promoted cyclization in dioxane without any transition metal. A one-pot variant combining the synthesis of the thiourea and the cyclization was also demonstrated. High yields were obtained, and a variety of functional groups were tolerated under these conditions. Transition-metal-free, mild reactive conditions, wide application scope, and shorter reaction times make this method superior to the reported methods for the synthesis of 2-substituted benzothiazoles and suitable for combinatorial format.