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A photocatalyzed and highly efficient trifluoromethylation of N-arylvinylsulfonamides using commercially available CF3SO2Cl as the trifluoromethyl radical source under blue LEDs is reported. The reaction proceeds through radical cyclization under mild conditions. An investigation of the substrate scope is performed to establish a general, synthetically useful protocol for the synthesis of novel trifluoromethylated 1,3-dihydrobenzo[c]isothiazole 2,2-dioxides in moderate to high yields. This method is also successfully applied for the synthesis of difluoromethylated and trifluoroethylated 1,3-dihydrobenzo[c]isothiazole 2,2-dioxides in good to excellent yields.

An asymmetric [3 + 2] cycloaddition of vinyl ethylenecarbonates (VECs) and (E)-3-arylvinyl substituted benzo[d] isothiazole 1,1-dioxides has been developed using the Pd complex of a bidentate phosphoramidite (Me-BIPAM) as the catalyst, providing a wide variety of chiral multistereogenic vinyltetrahydrofurans in good yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, 99% ee).

Based on esters of nicotinic and isonicotinic acids with hydroxybenzaldehydes, a series of functionally substituted derivatives containing isoxazole and isothiazole heterocycles in the molecule have been synthesized. Azomethines were obtained by condensation of nicotinates and isonicotinates with p-bromoaniline and m-aminophenol, which have been reduced with sodium triacetoxyborohydride to give the corresponding amines. Acylation of amino derivatives of nicotinates and isonicotinates with 5-arylisoxazole- and 4,5-dichloroisothiazolecarbonyl chlorides leads to the esters and amides with isoxazole and isothiazole residues.

Natural and synthetic derivatives of acridine and pyrimidoquinoline series are of considerable interest for study as antiviral, antitumor, antibacterial, antiparasitic agents; they are also useful in the treatment of Alzheimer’s disease. The combination of acridine and pyrimidoquinoline cycles with other pharmacophore groups can lead to a synergistic effect of their properties, the appearance of new types of biological activity, as well as a reducing of the severity of side effects. The synthesis of new derivatives of 8,9,10,12-tetrahydrobenzo[a]acridin-11(7H)-one and 10,12-dihydrobenzo[ f ] pyrimido [4,5- b ] quinoline-9,11 (7H, 8H)-dione containing isoxazole, isothiazole heterocycles, ferrocene fragment, as well as nicotinic and isonicotinic acid residues covalently attached via ester groups to different positions of the aromatic nucleus, is described. A three-component cascade condensation of aromatic amines, aldehydes and cyclic β —dicarbonyl compounds was carried out by refluxing in butanol. The heat effects of the cyclization reaction have been determined using the DFT / B3LYP1 / MIDI method. The cytotoxic activity of the synthesized compounds was assessed on four different cancer cell lines (RKO, COLO320, LS174T, SW480).

Curcumin is a chemical compound with antioxidant properties as well as strong anti-inflammatory, antiviral, analgesic, antimicrobial and antitumor effect, contained in the tuberous rhizomes of the turmeric plant (Curcuma longa). Curcumin derivatives are being intensively studied as potential drugs – antitumor drugs for the treatment of certain forms of cancer. The presence of reactive functional groups makes curcumin a convenient starting compound for the further chemical modification. The esters of curcumin and 5-phenylisoxazole-3-carboxylic acid, 5-(p-tolyl)isoxazole-3-carboxylic acid, 4,5- dichloroisothiazole-3-carboxylic acid and adduct of 5-(p-tolyl)isoxazol-3-carbaldehyde with curcumin were synthesized. Esters were obtained by acylation of curcumin with heterocycle-containing carboxylic acid chloride in diethyl ether in the presence of triethylamine. The IR and NMR spectra of the obtained compounds are described.

The developments in the synthesis of the five-membered heterocycles with one pnictogen (As, Sb, Bi) heteroatom have in the last 15 years or so been practically focused only on three types of compounds: saturated or unsaturated pnictogenoles, monofused pnictogenoles, and diffused pnictogenoles, where the fused ring is benzene, thiophene, isothiazole, benzothiophene, or benzofuran. Trendy is preparation and tuning of the optoelectronic properties of the target compounds, their complexes or polymers, respectively. Almost all syntheses of nearly all systems are based on transmetallation of lithium (for 1,3-diene known as Ashe's method), potassium, Grignard, copper, titanium, or zirconium species (Fagan–Nugent zirconium metallacycle-transfer method), regardless of whether the system is saturated (as is the case for the majority of compounds) or unsaturated.

An efficient and straightforward Pd-catalysed synthesis of diversely substituted sultams utilising ynamides and boronic acids is disclosed; toluene was found to be the most suitable solvent for this transformation. This strategy has been successfully applied to generate dihydrobenzo[d]isothiazole 1,1-dioxides and dihydro-2H-benzo[e][1,2]thiazine 1,1-dioxides. The advantages of this protocol are good functional group tolerance, broad substrate scope, high-yielding reaction and low catalyst loading to access benzofused sultams with five-/six-membered rings. The synthetic utility has been demonstrated by a gram-scale synthesis. A plausible catalytic cycle involving carbopalladation has been proposed for this transformation.

A Rh(III)-catalyzed annulative coupling of 3,5-diarylisothiazoles and alkynes is reported. The N-S bond in the isothiazole ring acts as an internal oxidant to regenerate the Rh(III) species in combination with an external Cu(II) oxidant, and the corresponding 1:2 coupling products are obtained. The remarkable difference in the reaction outcome between isothiazoles and the relevant isoxazoles has been investigated by DFT calculations, revealing that the relative stability of the enolate intermediates dictates the product selectivity.

The chemistry of isothiazoles is being intensively developed, which is evidenced by the wide range of selective transformations involving the isothiazole heterocycle and the high biological activity of its derivatives that can be used as effective new drugs and plant protection chemicals. Some representatives of isothiazoles have proven to be synergists of bioactive substances, which opens the way to lower the doses of drugs used and is especially important in cancer chemotherapy. In the framework of the present review, the accomplishments in the chemistry of isothiazoles over the past 18 years are examined, whilst current strategies for the synthesis of isothiazole-containing molecules and key directions of studies in this field of heterocyclic chemistry are discussed. Considerable attention is paid to chlorinated isothiazoles and strategies for their use in the synthesis of biologically active substances. In addition, a comprehensive review of existing literature in the field of metal complexes of isothiazoles is given, including the results and prospects for the practical use of isothiazole–metal complexes as catalysts for cross-coupling reactions in aqueous and aqueous–alcoholic media (‘green chemistry’).1 Introduction2 Synthesis by Ring-Forming Reactions2.1 Intramolecular Cyclization2.2 (4+1)-Heterocyclization2.3 (3+2)-Heterocyclization2.4 Syntheses by Ring Transformations3 Isothiazoles by Ring Functionalization Reactions: Nucleophilic Substitution, Cross-Coupling and Side-Chain Functionalization4 Selected Syntheses of Biologically Active Isothiazole Derivatives5 Isothiazoles in the Synthesis of Transition-Metal Complexes and in Metal-Complex Catalysis6 Conclusion

Acylation of vanillin with isonicotinoyl chloride gave 4-formyl-2-methoxyphenyl pyridine-4-carboxylate which was converted into a number of functional derivatives, including those containing isoxazole and isothiazole heterocycles. In particular, the condensation of the title compound with primary amines afforded the corresponding Schiff bases. 4-Formyl-2-methoxyphenyl pyridine-4-carboxylate and one of the Schiff bases derived therefrom were reduced with sodium triacetoxohydridoborate to the corresponding alcohol and amine which were acylated with 5-arylisoxazole- and 4,5-dichloroisothiazole-3-carbonyl chlorides to obtain esters and amides having isoxazole and isothiazole fragments. The synthesized compounds readily formed complexes with palladium(II) chloride, which showed a high catalytic activity in the Suzuki reaction of 3-bromobenzoic acid with 4-methoxyphenylboronic acid in water in the absence of an organic solvent.

An efficient organocatalytic diastereo- and enantioselective formal [3 + 2] cycloaddition reaction of α-isocyanoacetates with saccharin-derived 1-azadienes catalyzed by a dihydroquinine derived squaramide catalyst has been investigated, and it furnished the corresponding directly linked benzo[d]isothiazole 1,1-dioxide-dihydropyrroles with two adjacent tertiary-quaternary stereocenters in high yields (up to 98%), with moderate to excellent stereoselectivities (up to >20 : 1 dr and 97% ee) under mild conditions.

Aquatic contamination by heavy metals is a major concern for the serious negative consequences it has for plants, animals, and humans. Among the most toxic metals, Cd(II) stands out since selective and truly efficient methodologies for its removal are not known. We report a novel multidentate chelating agent comprising the heterocycles thiadiazole and benzisothiazole. 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide (AL14) was synthesized from cheap saccharin and characterized by different techniques, including single crystal X-ray crystallography. Our studies revealed the efficiency and selectivity of AL14 for the chelation of dissolved Cd(II) (as compared to Cu(II) and Fe(II)). Different spectral changes were observed upon the addition of Cd(II) and Cu(II) during UV-Vis titrations, suggesting different complexation interactions with both metals. UIDB/04326/2020, UIDB/04564/2020, ALG-01-0145-FEDER-022121, SFRH/BD/130407/2017 info:eu-repo/semantics/publishedVersion

Blockade of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway is an attractive strategy for immunotherapy. A novel series of compounds bearing a benzo[d]isothiazole scaffold were developed, among which CH20 exhibited promising activity, with an IC50 value of 8.5 nM. Further cell-based PD-1/PD-L1 blockade bioassays indicated that CH20 can inhibit the PD-1/PD-L1 interaction at the cellular level, with an EC50 value of 5.6 μM CH20 could have better potency in restoring the activity of effector cells, as the maximal luminescence values (RLUmax) of CH20 were equivalent to those of PD-L1 mAbs. The docking analysis of CH20 with the PD-L1 dimer complex (PDB ID: 6R3K ) confirmed that CH20 is a promising lead compound for the development of inhibitors of the PD-1/PD-L1 interaction. The preliminary structure-activity relationship was investigated in this paper, with the aim of future drug development.

A rhodium-catalyzed oxidative annulation of benzimidates with elemental sulfur for the direct construction of isothiazole rings is reported. The proposed reaction mechanism involving Rh(I)/Rh(III) redox is supported by a stoichiometric reaction of metallacycle species as well as DFT calculations. This method is also applicable to selenium cyclization to produce isoselenazole derivatives. The alkoxy substituent at C3 can be used for further functionalization of the azole core.

An efficient synthesis of bisisothiazole-4-yl disulfides via the demethoxylative thioannulation of alkynyl oxime ethers with odorless elemental sulfur has been first developed. This transformation involves the N-O bond cleavage, the formation of multiple C-S and N-S bonds, providing an efficient way for constructions of both isothiazoles and disulfides. Straightforward elaboration of the products to isothiazole thioethers expands the synthetic utility of this reaction.

The importance of isothiazole and of compounds containing the isothiazole nucleus has been growing over the last few years. Isothiazolinones are used in cosmetic and as chemical additives for occupational and industrial usage due to their bacteriostatic and fungiostatic activity. Despite their effectiveness as biocides, isothiazolinones are strong sensitizers, producing skin irritations and allergies and may pose ecotoxicological hazards. Therefore, their use is restricted by EU legislation. Considering the relevance and importance of isothiazolinone biocides, the present review describes the state-of-the-art knowledge regarding their synthesis, antibacterial components, toxicity (including structure-activity-toxicity relationships) outlines, and (photo)chemical stability. Due to the increasing prevalence and impact of isothiazolinones in consumer's health, analytical methods for the identification and determination of this type of biocides were also discussed., The authors would like to acknowledge ANI for the support of the Project FAMEST 24529 by Portugal 2020 Programme. This project was supported by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through Foundation for Science and Technology (FCT) (Projects UID/QUI/00081/2019 and POCI-01-0145-FEDER-030219).

Novel quinoline containing 3-piperazin-1-yl-benzo[d]isothiazole 4a and 4b and 3-piperidin-4-yl-benzo[d]isoxazole 5c were synthesized and characterized by spectral, single crystal XRD and DFT studies. Hirshfeld surface, electrostatic potential maps were obtained respectively from SCXRD and DFT studies. These compounds were analysed for in vitro antimicrobial activity and correlated with energy difference (ΔE) between HOMO and LUMO energy levels obtained from DFT and correlated with ΔE of standard drug to explain the activity. Further the antimicrobial activity was corroborated by docking against various target enzymes. The present work provided some hints for developing novel antimicrobial quinoline derivatives.

Three-component cascade cyclocondensation of naphthalen-2-amine with cyclic β-dicarbonyl compounds and isoxazole- or isothiazolecarbaldehydes afforded new structural analogs of alkaloids containing isoxazole and isothiazole fragments.

The radiationless decay of the isothiazole and thiazole molecules in the gas phase is investigated by a combination of static MS-CASPT2 computations with dynamics simulations, and some deactivation pathways are identified leading from the lowest excited singlet (S1) state back to the electronic ground (S0) state. The dominant relaxation pathway of the excited isothiazole is found to involve out-of-plane ring deformation (ring puckering) at the C4=C5(H8) S1 moiety, while the excited-state decay of thiazole can proceed through the ring puckering and S1 C2 bond cleavage pathways both of which happen at the S1 C2(H6) = N3 moiety. On the basis of the calculation results, we suggest that both ring-puckering and ring-opening routes should play rather important roles in the photophysics and photochemistry of heterocyclic molecules, and the position of the N atom in the heterocyclic ring has an effect on the excited state deactivation.

By acylation of substituted 2-aminoarylpyrimidines with 5-phenyl(p-tolyl)isoxazole- and 4,5-dichloroisothiazole-3-carbonyl chlorides new amides of pyrimidine series were obtained.

The reactivity of the 4-amino-2,3-dihydro-1H-1λ6-isothiazole-1,1-dioxide (β-amino-γ-sultam) framework has not been studied sufficiently. Here we describe the chemical properties of this heterocyclic system toward electrophiles on spiranic and non-spiranic substrates. A variety of C-electrophiles (acetic anhydride, benzoyl chloride, DMFDMA, 4,4-dimethoxybutan-2-one) and heteroatom electrophiles (bromine, nitrosyl acetate) have been explored. Both the C-5 and 4-amino positions of the β-amino-γ-sultam system are able to undergo electrophilic reactions. Heteroatom electrophiles attack the C-5 position, whereas carbo-electrophiles affect the amino group. β-Amino-γ-sultams also were used as starting compounds for the synthesis of 6- or 7-substituted 1λ6-isothiazolo[4,5-b]pyridine-1,1-dioxides through condensation reaction and palladium-catalyzed oxidative coupling.

Alkylation of fluorophenols and phenolic aldehydes with 5-phenyl(p-tolyl)-3-chloromethylisoxazole under the Williamson reaction conditions afforded the corresponding ethers. Condensation of the resulting phenolic aldehyde derivatives and 5-phenyl(p-tolyl)isoxazole-3-carbaldehydes with p-fluoroaniline resulted in fluorine-containing azomethines. Acylation of fluorinated amines with 5-(p-tolyl)isoxazole- and 4,5- dichloroisothiazole-3-carbonyl chlorides gave rise to fluorinated amides bearing isoxazole and isothiazole fragments, representatives of which showed a synergistic effect in compositions with insecticides.

A reaction sequence involving transformations of 5-(4-methylphenyl)isoxazole and 4,5-dichloroisothiazole derivatives containing an amidoxime group at position 3 allowed to synthesize the respective 3,5-isoxazolyl(isothiazolyl)-substituted 1,2,4-oxadiazoles. Selective recyclization of 4,5-dichloro-3-(1Н-tetrazol-5-yl)isothiazole and 5-(4-methylphenyl)-3-(1Н-tetrazol-5-yl)isoxazole gave 2,5-isoxazolyl-(isothiazolyl)-substituted 1,3,4-oxadiazoles. The obtained compounds combining three azole heterocycles in one molecule formed palladium complexes that showed high catalytic activity in Suzuki reactions in aqueous and aqueous alcohol media. The bimetallic reusable Pd/Fe catalyst obtained from palladium polyazole complex retained high catalytic activity after five uses.

A novel series of fused-benzensulfonamide 2-N-(pyrazol-3-yl)methylbenzo[d]isothiazole-1,1-dioxide derivatives was designed and synthesized as metabolically stable T-type calcium channel inhibitors. Several compounds, 9, 10, and 17, displayed potent T-type channel inhibitory activity. Among them, compounds 10 and 17 showed good metabolic stability in human liver microsomes, and low hERG channel and CYP450 inhibition. Compound 10 exhibited diabetic neuropathic pain-alleviating effects in a streptozotocin-induced peripheral diabetic neuropathy (PDN) model. The maximum efficacy of compound 10, which was 3-fold more potent than gabapentin, was observed at 1h after administration, and co-administration of compound 10 with gabapentin showed a considerable synergic effect.

An operationally simple and user-friendly process to access privileged scaffolds such as acids, amides and isothiazoles has been devised employing β-ketodithioesters for the first time. Remarkably, the new protocol involves combination of C C bond cleavage and C O/C N/N S bond formations in one-pot. Aqueous ammonia led to the formation of skeletally distinct amide and isothiazole, whereas aqueous NaOH enabled the formation of aromatic acid near quantitative yield. This practical approach, which can dramatically streamline the synthesis of simple molecules, is highly chemoselective, cost-effective, amenable to gram scale, insensitive to moisture as well as bears high functional group compatibility.

Conjugates of ferrocene and 4,5-dichloroisothiazole were synthesized, where the ferrocene and isothiazole moieties are linked through various structural fragments. The acylation of ferrocene with 4,5- dichloroisothiazole-3-carbonyl chloride gave (4,5-dichloroisothiazol-3-yl) ferrocenyl ketone; the acylation of aminomethylferrocene furnished the corresponding amide. The esterification of ferrocene-1,1′-dicarboxylic acid with 4,5-dichloroisothiazol-3-yl-methanol resulted in the formation of the corresponding ester. The condensation of 1,1′-diacetylferrocene with 4,5-dichloroisothiazole-3-carbaldehyde afforded ferrocenophane containing 4,5-dichloroisothiazole moieties.

Enyne-substituted benzoisothiazole derivatives have been synthesised under one-pot, operationally simple conditions using 2-iodo-N-(trimethylsilylethynyl)benzenesulfonamides and terminal alkynes as starting materials and a palladium–copper-based catalytic system. The structure of these heterocycles has been demonstrated by NMR spectroscopy and confirmed by X-ray crystallographic analysis. A plausible reaction mechanism has been proposed.

Transition-metal-free inverse electron-demand aza Diels-Alder and domino [4+2]/[2+2] cycloaddition reaction of arynes and N-sulfonyl ketimines has been demonstrated. This novel, mild, and efficient protocol allows rapid access to isothiazole dioxide-fused dihydroquinoline or dihydrocyclobutaquinoline derivatives selectively by simply varying the equivalents of aryne precursors. The application of this method has been amply illustrated in the synthesis of 2,4-diarylquinolines.

An efficient route to diverse 3-sulfonated-2,3-dihydrobenzo[d]isothiazole 1,1-dioxides is achieved through a three-component reaction of 2-ethynylbenzenesulfonamides, DABCO-bis(sulfur dioxide), and aryldiazonium tetrafluoroborates. The corresponding sulfonated benzosultams are produced in moderate to good yields. During the reaction process, the in situ generated arylsulfonyl radical via addition of an aryl radical to sulfur dioxide and the subsequent single electron transfer would be the key steps for the final outcome. DABCO acts as the carrier for single electron transfer, as well as a base to promote the C–N bond formation.

Thanks to the progress in oncology, pharmacological treatment of cancer is gaining in importance and in the near future anti-cancer chemotherapeutics are expected to be the main method of treatment for cancer diseases. What is more, the search for new anti-cancer compounds with the desired application properties is constantly underway. As a result of designed syntheses, we obtained some new N&rsquo, substituted 5-chloro-3-methylisothiazole-4-carboxylic acid hydrazide derivatives with anticancer activity. The structure of new compounds was determined by mass spectrometry (MS), elemental analysis, proton nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), 1H-13C NMR correlations and infrared spectroscopy (IR). Moreover, the structures of the compounds were confirmed by crystallographic examination. The antiproliferative MTT tests for 11 prepared compounds was conducted towards human biphenotypic B cell myelomonocytic leukemia MV4-11. SRB test was used to examine their potential anticancer activity towards human colon adenocarcinoma cell lines sensitive LoVo, resistant to doxorubicin LoVo/DX, breast adenocarcinoma MCF-7 and normal non-tumorigenic epithelial cell line derived from mammary gland MCF-10A. The most active compound was 5-chloro-3-methyl-N&prime, [(1E,2E)-(3-phenyloprop-2-en-1-ylidene]isothiazole-4-carbohydrazide, which showed the highest antiproliferative activity against all tested cell lines.

A convenient molecular diversity-oriented synthesis of various functional sulfur-containing heterocyclic scaffolds mainly including isothiazole, 2H-1,3-thiazine, and thiazolidine via different methods from α-substituted cyanoacetamides is described. The target molecules have been identified on the basis of analytical spectral data, which may serve as useful structural subunits in the fields of drug discovery.

A robust method for the synthesis of benzo[c]isothiazole 2-oxides has been developed providing a range of functionalized derivatives starting from anilines and DMSO. The reaction sequence can be performed on a gram scale and leads to products that can easily be modified by standard cross-coupling reactions.

Herein, we present joint experimental and theoretical studies on newly designed thiophene- or furan-based oxazole, isoxazole, and isothiazole derivatives. Our synthetic approach towards the preparation of target compounds is based on Van Leusen reaction. By following this reaction, oxazoles (1 and 2) containing the pertinent heterocyclic systems were obtained from the reaction of suitable furan or thiophene derivatives with tosylmethyl isocyanide (TOSMIC). Hereby, three ring systems of furan or thiophene, linked to the oxazole rings at their 2- and 5-positions (3 and 4), were also successfully synthesized for the first time. Reaction of the starting materials containing acetyl groups in their 2-position with dimethyl acetal and following the treatment by hydroxylamine hydrochloride, desired isoxazole derivatives (5 and 6), were obtained. Additionally, isothiazole derivatives (7 and 8) were prepared by following the similar approach to the isoxazole synthesis. Whole of these cyclization reactions occurred with good to excellent yields. Structural analyses of the synthesized compounds were performed by appropriate spectroscopic methods (UV-vis, FT-IR, LC-MS, 1H-NMR, 13C-NMR, and elemental analysis). We also carried out theoretical studies for identifying the structure-activity relationship and determining chemical properties of the studied molecules. For this purpose, we obtained information about structural properties (bond lengths, bond angles, dihedral angles, and dipole moments), band gap energies, and spectroscopic characteristics (UV-vis, FT-IR, 1H-NMR, and 13C-NMR) of the target compounds.

From (4,5-dichloroisothiazol-3-yl)phenylmethanol by Ritter reaction a substituted acetamide was synthesized that at hydrolysis with HCl afforded (4,5-dichloroisothiazol-3-yl)phenylmethylamine hydrochloride. By reaction of (5-arylisoxazol-3-yl)- and 4,5-dichloroisothiazol-3-yl)arylmethanol with thionyl chloride the corresponding (1,2-azol-3-yl)arylchloromethanes were obtained. At treatment with O- and N-nucleophiles chlorine atom in chloromethylеne fragment of obtained compounds was substituted by residues of benzylamine, morpholine, vanillin, and ethoxy group.

A synthetic method for obtaining a wide variety of isothiazoles by the Rh-catalyzed transannulation of 1,2,3-thiadiazoles with alkyl, aryl, and heteroaryl nitriles, which proceeds via an α-thiavinyl Rh-carbenoid intermediate, was developed. The results suggest that during its reaction with nitriles, the α-thiavinyl carbene acts as an umpolung 1,3-dipole equivalent, in contrast to its behavior during its reaction with alkynes. The developed method was successfully employed to synthesize pentaoligomeric arylene compounds consisting of three benzene and two isothiazole rings.

Homogenous and heterogeneous palladium catalysts with functionalized izoxazole and isothiazole ligands were developed for the cross-coupling reactions. The catalysts possessed high activity and were suitable for the repeated use. Compared with commonly used organic solutions, application of water and its mixtures with methanol as a reaction medium significantly intensifies catalysis with no side being formed. The obtained results are promising for the development of effective and ecologically friendly technologies of synthesis of important compounds such as polyfunctional biaryls, arylated olefins, acetylenes and their heterocyclic analogs.

Thiazole derived compounds have great potential in medicinal- and agro-chemistries, catalysis, cosmetic industry, corrosion protection, light harvesting, production of light-emitting diodes (LEDs), photochromes and molecular switches or nonlinear optical materials. In spite of that, not much attention has been paid to the coordination chemistry of this class of versatile and polyfunctional heterocyclic ligands. This review intends to systematize the existing information in this field and to highlight some perspectives in the synthesis and applications of 1,3-thiazole, isothiazole and thiadiazole metal complexes.

An efficient, metal-free, NBS-mediated thiocyanation protocol has been developed for the synthesis of (6-(hydroxyimino)-2-thiocyanatocyclohex-1-en-1-yl)(phenyl)methanone derivatives from cyclohexene-fused isoxazoline N-oxides under mild conditions. This rapid, one-pot transformation is achieved in acetonitrile, and provides access to diverse SCN-containing compounds bearing a wide range of functional groups in good to excellent yields. Moreover, an SCN containing product was further utilized for the synthesis of cyclohexanone ring-fused isothiazole derivatives.

Under visible light irradiation, 2-ethynylbenzenesulfonamides react with Togni's reagent in the presence of a photocatalyst leading to 3-(2,2,2-trifluoroethylidene)-2,3-dihydrobenzo[d]isothiazole 1,1-dioxides in good yields. This transformation proceeds efficiently at room temperature through a photo-initiated trifluoromethylation. The subsequent C–N bond formation produces the corresponding benzosultams.

Unprecedented three-dimensional heterocycles are introduced, and their scaffold functionalization is described. A robust synthetic method utilizing cheap commercially available starting materials leads to a wide range of products on gram scale. The product portfolio can be expanded by applying newly devised building blocks with relevance for automated parallel synthesis in cross-coupling reactions.

The synthesis, evaluation, and structure-activity relationships of a class of acyl guanidines which inhibit the BACE-1 enzyme are presented. The prolinyl acyl guanidine chemotype (7c), unlike compounds of the parent isothiazole chemotype (1), yielded compounds with good agreement between their enzymatic and cellular potency as well as a reduced susceptibility to P-gp efflux. Further improvements in potency and P-gp ratio were realized via a macrocyclization strategy. The in vivo profile in wild-type mice and P-gp effects for the macrocyclic analog 21c is presented.

In this work, the structural, topological and vibrational properties of an isothiazole derivatives series with antiviral activities in gas and aqueous solution phases were studied by using DFT calculations. The self consistent reaction field (SCRF) method was combined with the polarized continuum (PCM) model in order to study the solvent effects and to predict their reactivities and behaviours in both media. Thus, the 3-mercapto-5-phenyl-4-isothiazolecarbonitrile (I), 3-methylthio-5-phenyl-4-isothiazolecarbonitrile (II), 3-Ethylthio-5-phenyl-4-isothiazolecarbonitrile (III), S-[3-(4-cyano-5-phenyl)isothiazolyl] ethyl thiocarbonate (IV), 5-Phenyl-3-(4-cyano-5-phenylisothiazol-3-yl) disulphanyl-4-isothiazolecarbonitrile (V) and 1,2-Bis(4-cyano-5-phenylisothiazol-3-yl) sulphanyl Ethane (VI) derivatives were studied by using the hybrid B3LYP/6-31G* method. All the properties were compared and analyzed in function of the different R groups linked to the thiazole ring. This study clearly shows that the high polarity of (I) probably explains its elevated antiviral activity due to their facility to traverse biological membranes more rapidly than the other ones while in the (IV) and (V) derivatives the previous hydrolysis of both bonds increasing their antiviral properties inside the cell probably are related to their low S-R bond order values. In addition, the complete vibrational assignments and force constants are presented.

An enantioselective Friedel–Crafts alkylation reaction of indoles with cyclic N-sulfonyl ketimino esters was developed. Under the optimized conditions using a chiral copper(II) triflate-bisoxazoline complex as the catalyst, a range of N-sulfonyl ketimino ester derivatives and indoles reacted smoothly to afford indole-containing chiral cyclic α-amino esters bearing tetrasubstituted α-stereogenic centers [3-ethoxycarbonyl-3-(3-indolyl)-2,3-dihydrobenzo[d]isothiazole 1,1-dioxides] in excellent yields and with high enantioselectivities (up to 99% ee). Pyrrole and N,N-dimethylaniline were also investigated as aromatic substrates to afford the corresponding products with good results. An asymmetric induction model was then proposed on the basis of the observed absolute configuration of the product 3-ethoxycarbonyl-3-(5-bromo-3-indolyl)-2,3-dihydrobenzo[d]isothiazole 1,1-dioxide. Synthetic transformations to convert the products into cyclic chiral N-sulfonamido alcohols and the deprotection of the sulfonamides were performed. This study provides an efficient approach to chiral α-tetrasubstituted indolic α-amino acids as potential building blocks for peptides and biologically active molecules.

This review surveys literature methods for the synthesis of sulfamates. The synthesis of a broad number of cyclic sulfamates (sulf­amidates) in recent years is highlighted. 1 Introduction 2 Synthesis of Acyclic Sulfamates 2.1 From Alcohols and Phenols 2.2 From Imidazolylsulfonates 2.3 From Olefins 2.4 From Isothiazole Dioxides 3 Synthesis of Cyclic Sulfamates (Sulfamidates) 3.1 From Diols and Epoxides 3.2 From Amino Alcohols 3.3 By Rhodium- and Ruthenium-Catalyzed Intramolecular Amination of Sulfamates 3.4 From Cyclic Sulfamate Imines 3.5 From the Sulfamoyl Aziridine Moiety 3.6 From Aziridines 3.7 Using Metallonitrene/Alkyne Metathesis 4 Conclusions

We have discovered a novel series of isothiazole-based phenylpropanoic acids as GPR120 agonists. Extensive structure–activity relationship studies led to the discovery of a potent GPR120 agonist 4x, which displayed good EC50 values in both calcium and β-arrestin assays. It also presented good pharmaceutical properties and a favorable PK profile. Moreover, it demonstrated in vivo antidiabetic activity in C57BL/6 DIO mice. Studies in WT and knockout DIO mice showed that it improved glucose handling during an OGTT via GPR120. Overall, 4x possessed promising antidiabetic effect and good safety profile to be a development candidate.

A novel transformation is reported for the reaction of terminal or internal alkynes with the nitrene precursor PhI=NTs (Ts=p-toluenesulfonyl) in the presence of catalytic amounts of Tp(Br3)Cu(NCMe) (Tp(Br3)=hydrotris(3,4,5-tribromo-pyrazolylborate). Two products containing an imine functionality have been isolated from the reaction mixtures, identified as sulfinamides and isothiazoles. The former correspond to the formal reduction of the sulfone group into sulfoxide, whereas the latter involves the insertion of an alkyne carbon atom into the aromatic ring of the N-tosyl moiety., Support for this work was provided by the MINECO (CTQ2014-52769-C3-R-1, CTQ2014-57761-R, Severo Ochoa Excellence Accreditation 2014-2018 SEV-2013-0319, Red Intecat CTQ2014-52974-REDC) and by a FPU fellowship (M.R.R.). We thank Prof. Antonio Echavarren for helpful comments and discussions.