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Abstract: A new series of mono-N-sulfonamides of C 2-symmetrical 2′-bipyrrolidine have been designed, synthesized, and successfully applied as the organocatalysts to the enantio- and diastereoselective Michael addition of 4H-thiopyran-4-one to a variety of nitroolefins. Catalyst 10 was identified in the examinations to exhibit more superior catalytic ability than the traditional chiral pyrrolidine catalysts, giving high chemical yields, excellent diastereo- and enantioselectivities (up to 99:1 dr and 98% ee). The tert-butyl sulfonamide functionality of catalyst 10 is speculated to play crucial roles in the transition state as both bulky group and hydrogen-bond acceptor. Application of a representative Michael adduct has been also studied and proven to be useful for the diversity-oriented synthesis of enantiopure multiring heterocycles through a unique common bicyclic nitrone intermediate. [Copyright &y& Elsevier]

A cascade reaction of (E)-5-(arylamino)pent-3-en-1-ols and thiols with various aldehydes in the presence of 30 mol % BF3⋅OEt2 in 1,2-dichloroethane at 80 °C affords a novel class of trans-fused hexahydro-1H-pyrano[3,4-c]quinolines and hexahydro-1H-thiopyrano[3,4-c]quinolines in good to excel¬lent yields with high selectivity. The condensation of (Z)-S-(arylamino)pent-3-en-1-ol with aldehydes provides the corre¬sponding cis-fused products under similar conditions. [ABSTRACT FROM AUTHOR]

Give it some stick: UV irradiation of spirothiopyran in an aqueous solution of gold nanoparticles (AuNPs) gives AuNP aggregates. The aggregate size is tuned by the photoirradiation time and the aggregation is facilitated by the covalent binding of photoisomerized spirothiopyran to the surface of the AuNPs. This binding decreases the electrostatic repulsion between the AuNPs. [ABSTRACT FROM AUTHOR]

While both 1,8-diazabicyclo[5.4.0]undec-7-ene and triphenylphosphine catalyze tandem Baylis–Hillman reaction/disulfide cleavage of 2,2′-dithiodibenzaldehyde independently, when used together as a dual-catalyst system, the overall yields of the cyclized 2H-1-benzothiopyrans are consistently greater and the reaction time decreases dramatically. Supplemental materials are available for this article. Go to the publisher's online edition ofSynthetic Communications® to view the free supplemental file. [ABSTRACT FROM AUTHOR]

Natural bond orbital (NBO) interpretation and hybrid density functional theory (hybrid-DFT: B3LYP/Def2-TZVPP)-based methods were used to investigate the impacts of the generalized anomeric effects (GAE), electrostatic, and steric interactions on the conformational properties ofcisandtransisomers of 2-fluoro-, 2-chloro-, and 2-bromotetrahydrothiopyran S-oxide (1–3). The results obtained showed that thetrans-axial configurations are the most stable forms of compounds1–3. Based on the results obtained, the instability of the second lowest energy-minimum (cis-equatorial configuration, with axial S˭O and equatorial C‒X bonds, X = halogen atoms) increases from compound1to compound3. This trend is also observed for the third lowest energy-minimum (i.e., thetrans-equatorial configuration). Contrary to the trend observed for thecis-andtrans-equatorial forms, the instability of thecis-axial form compared to thetrans-axial form, increases from1to2but decreases slightly from2to3. The correlations between the GAE, bond orders, steric effects, ΔG, Δμ, structural parameters, and conformational and configurational behaviors of compounds1–3have been investigated. Supplemental materials are available for this article. Go to the publisher's online edition ofPhosphorus, Sulfur, and Silicon and the Related Elementsto view the free supplemental file. [ABSTRACT FROM AUTHOR]

A novel thia-Prins bicyclization approach has been developed for the first time for the synthesis of hexahydro-2H-thieno[3,2-c]thiopyran derivatives from the coupling of homoallylic mercaptans such as hex-3-ene-1,6-dithiol with various aldehydes using 10 mol % InBr3 in dichloromethane with high selectivity. In addition, the coupling of (E)-N-(6-mercaptohex-3-enyl)-4-methylbenzenesulfonamide with aldedydes affords the corresponding N-tosyloctahydrothiopyrano[4,3-b]pyrrole derivatives in good yields. This reaction is a stereoselective affording trans-fused product from E-homoallyllic mercaptan and cis-fused product from Z-homoallyllic mercaptan. [ABSTRACT FROM AUTHOR]

Abstract: Enantiomerically pure (2S,6S)-2,6-diphenyltetrahydro-2H-thiopyran, (2S)-2-phenyltetrahydro thiophene, and (2S)-2-phenyltetrahydro-2H-thiopyran were prepared in 70–72% yields and with 86–99% ee via cyclization of the corresponding dimesylate in an SN2 cyclization reaction using sodium sulfide nonahydrate. The results on the application of various chiral sulfides in asymmetric Baylis–Hillman reactions are also described. [Copyright &y& Elsevier]

Abstract: An efficient synthesis of novel pentacyclic thiopyrano indole-annulated benzo-δ-sultone derivatives is achieved via intramolecular domino Knoevenagel-hetero-Diels–Alder reaction of 2-formylphenyl (E)-2-phenylethenyl sulfonates and indoline-2-thiones in aqueous medium. The products are formed in good yields with high regio- and stereoselectivity. [Copyright &y& Elsevier]

Abstract: Single crystal X-ray diffraction reveals that 4,4′-bis(tetrahydrothiopyranyl) crystallizes in an equatorial–equatorial geometry with a gauche conformation along the central carbon–carbon bond. B3LYP/6-311G** and MP2/6-311G** calculations show that the antiperiplanar conformation is higher in energy than the gauche one because of sulfur induced stretching and widening of the cyclohexane-like rings. Calculations at various levels of theory suggest that in the antiperiplanar region the twisting coordinate of 4,4′-bis(tetrahydrothiopyranyl) exhibits a very shallow double-well potential. The gauche molecular structure of 4,4′-bis(tetrahydrothiopyranyl) thwarts efficient packing of its molecules in the solid state. [Copyright &y& Elsevier]

Three-component heterocyclization of 4-amino-5-carboxamido-1,2,3-triazole, thiopyran-3-one-1,1-dioxide, and aromatic aldehydes under ultrasonic and microwave irradiation was studied. Regardless of the reaction parameters, 5,6,7,9-tetrahydro-4 H-thiopyrano[3,2- d][1,2,3]triazolo[1,5- a]pyrimidine-8,8-dioxides were isolated as sole reaction products whose structures were proven with help of NMR data and X-ray analysis. [ABSTRACT FROM AUTHOR]

Abstract: Polyunsaturated conjugated thiocarbonyl compounds (thioxocarotenoids) occur as monomers or react instantaneously to give polyene substituted trithiacyclohexanes and 2H-thiopyrans. [Copyright &y& Elsevier]

A pair of enantiomers (1aand 1b) of an indole alkaloid containing dihydrothiopyran and 1,2,4-thiadiazole rings was isolated from an aqueous extract of the root of Isatis indigotica. The structures and absolute configurations of the enantiomers were determined by extensive spectroscopic analysis, especially 2D NMR, modified Mosher’s method, and electronic CD (ECD). The proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1aand 1bagainst influenza virus A/Hanfang/359/95 (H3N2) and HSV-1 are also discussed. [ABSTRACT FROM AUTHOR]

The one-pot, three-component Mannich reactions of thiopyran-4-one 1 with different aromatic aldehydes and aniline derivatives in the presence of catalytic quantities of ZrOCl2.8H2O (15 mol %) led to rapid and high yield formation of various 3-methylamino substituted derivatives of 1 at room temperature. Spectroscopic and X-ray analyses of the products suggested the formation of the anti stereoisomers as the major product of the reactions. [ABSTRACT FROM AUTHOR]

2-Methoxytetrahydropyran (1), -thiopyran (2) and -selenopyran (3) have been chosen as model compounds to investigate the origin of the anomeric effect (AE). The impacts of the hyperconjugation, electrostatic and steric interactions on the conformational preferences of compounds 1–3 have been analysed by means of complete basis set-4, hybrid-density functional theory (B3LYP/6-311+G**) based methods and natural bond orbital (NBO) interpretation. Both levels of theory showed that the axial conformations of compounds 1–3 are more stable than their equatorial conformations. The Gibbs free energy difference (G eq–G ax) values (i.e. ΔG eq–ax) between the axial and equatorial conformations increase from compound 1 to compound 2 but decrease from compound 2 to compound 3. Based on the NBO results obtained, the AE associated with the electron delocalisation [i.e. Σ(endo-AEeq + exo-AEeq) − Σ(endo-AEax + exo-AEax)] increase slightly from compound 1 to compound 2 but decrease from compound 2 to compound 3. Similar trend is also observed for the differences between the calculated total steric exchange energy values [i.e. Δ(TSEE)eq–ax]. On the other hand, the calculated differences between the dipole moment values of the axial and equatorial conformations [i.e. Δ(μeq–μax)] decrease from compound 1 to compound 3. These findings led to the proposal that the AE associated with the electron delocalisation (the hyperconjugation effect) is more significant for the explanation of the conformational preferences of compounds 1–3 than the electrostatic model. The correlations between the AE associated with the electron delocalisation, bond orders, TSEE, ΔG eq–ax, dipole–dipole interactions, structural parameters and conformational behaviours of compounds 1–3 have been investigated. [ABSTRACT FROM PUBLISHER]

Bis-fused donors composed of (thio)pyran-4-ylidene-1,3-dithiole and tetraselenafulvalene (1a, 2a) and their bis(methylthio) derivatives (1b, 2b) were synthesized. Cyclic voltamograms of all the donors consisted of four pairs of one-electron redox waves, and it was suggested that a positive charge of 1+* and 2+* distributed mainly on the (thio)pyran-4-ylidene-1,3-dithiole moiety. X-ray structure analysis revealed that (1b)PF6(C6H5Cl)0.5 and (2b)PF6(C6H5Cl) formed one-dimensional conducting stacks in which the donors were dimerized or tetramerized. In those salts, intramolecular charge disproportionation of the donors was suggested by X-ray structure analysis and density functional theory (DFT) calculation with UB3LYP/6-31G(d) basis function. A tight-binding band calculation suggested that these materials were band insulators. All the donors gave highly conducting TCNQ (7,7,8,8-tetracyanoquinodimethane) complexes and I3 salts (σrt = 0.3-19 S cm-1 on a compressed pellet) with very low activation energies of 0.017-0.040 eV, while single crystals of (1b)PF6(C6H5Cl)0.5 and (2b)PF6(C6H5Cl) exhibited semiconductive behavior with large activation energies (Ea = 0.16-0.22 eV). [ABSTRACT FROM AUTHOR]

A series of 6H-thiopyran-2,3-dicarboxylate derivatives 4a-d were synthesized and evaluated for their cytotoxic effect against HCT-15 colon and MCF-7 breast cancer cell lines using Sulforhodamine B (SRB) assay. The results showed that these compounds could exhibit a good cytotoxicity to both cell lines. In addition, these compounds were found to exhibit significant DNA-binding affinity. Ultraviolet--visible light (UV-Vis) spectroscopy was conducted to determine the ability of the ligand under analysis. The effect of ligand complexation on DNA structure led to overall affinity constants of K4a = 3.5 x 104 M-1, K4b = 6.4 x 104 M-1, K4c = 3.2 x 104 M-1, and K4d = 2.4 x 104 M-1. Our findings could provide new evidence showing the relationship between the chemical structure and biological activity and may be useful for the discovery of new anti-cancer drugs. [ABSTRACT FROM AUTHOR]

The reaction of benzothiete ( 1) and the bicyclic alkenes 5, 7, 9, or 12 shows a very high π side selectivity (de > 95%) in the formation of the polycyclic thiopyrans 6, 8, 10, 11, 13, and 14. [ABSTRACT FROM AUTHOR]

Abstract: An overview of syntheses and chemical properties of polyfluoroalkyl 2H- and 4H-thiopyrans, their hydrogenated (3,4- and 3,6-dihydrothiopyrans, and tetrahydrothiopyrans) and S-oxidized derivatives is presented. The first part is devoted to the synthetic methods starting from acyclic or cyclic precursors, and on multicomponent reactions. The second one deals with the chemical properties of thiopyran derivatives such as elimination reactions, [4+2] cycloadditions, sulfur or Cbond oxidations, and reactions with nucleophiles. The last part is focused on the biological evaluation of polyfluoroalkyl 2H-thiopyrans, especially as potential cardiotonic agents. [Copyright &y& Elsevier]

Abstract: A green, operationally simple and highly efficient one-pot three-component approach for the synthesis of spiro[indoline-3,4′-thiopyrano[2,3-b]indole] derivatives has been developed by the domino reaction of indoline-2-thione, isatin and ethyl cyanoacetate or malononitrile in ethanol at 80°C for just 20min. The significant advantages of this protocol are short reaction time, excellent yields, operational simplicity and formation of three new bonds in one operation from easily available starting materials. [Copyright &y& Elsevier]

Oxidation of 1,1′-[3-(methylsulfanylmethyl)tetrahydro-2 H-thiopyran-3,5-diyl]diethanone with equivalent amounts of potassium iodate in glacial acetic acid and hydrogen peroxide in tetrahydrofuran and chloroform gave the corresponding mono- and disulfoxides and disulfone, respectively. Reactions of the title compound with sodium tetrahydridoborate and hydroxylamine hydrochloride afforded mono- and dihydroxy derivatives and monooxime, respectively. [ABSTRACT FROM AUTHOR]

Synthesis of a phosphonopentapeptide enkephalin analogue was achieved from heterocyclic aminophosphonates via the coupling of Boc-Tyr-Gly-Gly-OH with phosphonodipeptide. The latter was formed by coupling Boc-Phe-OH with N-terminal α,α-disubstituted heterocyclic α-aminophosphonates. GRAPHICAL ABSTRACT [image omitted] [ABSTRACT FROM AUTHOR]

Abstract: The first example of a catalytic asymmetric thia hetero-Diels–Alder reaction, in which a chiral Lewis acid activates the thiocarbonyl dienophile, is described. The reactions catalyzed by copper(II)-bis(oxazolines) complexes of three dithioesters with simple dienes (such as cyclopentadiene or 2,3-dimethyl-1,3-butadiene) afford optically active dihydrothiopyrans with ees up to 82%. Some aspects of the reaction were investigated by computational means. [ABSTRACT FROM AUTHOR]

Abstract: An efficient catalyst-free synthesis of novel pentacyclic thiochromone-annulated thiopyranocoumarin derivatives is achieved via domino Knoevenagel-hetero-Diels–Alder reaction of 4-hydroxy dithiocoumarin and O-acrylated salicylaldehyde derivatives in H2O as solvent. The products are formed in good yields with high regio- and stereo-selectivity. [ABSTRACT FROM AUTHOR]

A facile and divergent synthesis of substituted pyridine-2,4(1H,3H)-diones and 4H-thiopyran-4-ones from readily available α-alkenoyl-α-carbamoyl ketene-S,S-acetals has been developed. Subjected to N,N-dimethylformamide at 125°C, α-alkenoyl-α-carbamoyl ketene-S,S-acetals underwent an intramolecular aza-nucleophilic vinyl substitution reaction, a formal [5C + 1N] annulation, to give the corresponding substituted pyridine-2,4(1H,3H)-diones in high yields, whereas in the presence of Na2S-9H2O in DMF at 75°C, tandem intermolecular and intramolecular thia-nucleophilic vinyl substitution reactions, a formal [5C + 1S] annulation, occurred to produce the corresponding substituted 4H-thiopyran-4-ones in good yields. [ABSTRACT FROM AUTHOR]

[Display omitted] Selectivity of nitrene addition to the C C S fragment depends on the oxidative state of the sulfur atom as has been exemplified on various derivatives of 3,4-dihydro-2 H -thiopyran under conditions of oxidative aminoaziridination. A unique structure with 2-thia-7-azabicyclo[4.1.0]heptane-2,2-dioxide core was obtained via addition of nitrene to the C C bond of thiopyran S , S -dioxide. For an unoxidized thiopyran, only en(phthaloyl)hydrazine resulted after cleavage of the initially formed aziridine. S -Oxide trapped the nitrene by the sulfur atom to form the sulfoximine leaving the double bond unaffected. [ABSTRACT FROM AUTHOR]

Abstract: We have designed and synthesized several basic and novel fused ring heterocycles by intramolecular hydroarylation with an efficiency and scope to develop intermediates of potential value. This method demonstrated consistent performance with arene–ene and arene–yne substrates of diverse structural features, including propargyl ethers, allyl thioethers, and propargyl thioethers resulting in 6-endo products. [Copyright &y& Elsevier]

2-Phenyl-1,1,3-tricyanopropene[α-(cyanomethyl)benzylidene-malononitrile] undergoes bromination with N-bromosuccinimide (NBS) to afford 2-phenyl-1,1,3-tricyano-3-bromopropene: [α(bromocyanomethyl)benzylidene malononitrile]. This bromo derivative undergoes reactions with sodium hydrogen sulfide, hydrazine hydrate, phenyl hydrazine, hydroxylamine hydrochloride, ethyl thioglycollate, urea derivatives, and cyanacetohydrazide to afford thiophene, 4H-pyridazines, 4H-oxazine and 4H-thiopyran, N-substituted pyrrole, and pyrrolo[1,2-b]pyridazine derivatives respectively. [ABSTRACT FROM AUTHOR]

A solvent-free reduction of 2,4,6-triarylthiopyrylium with NaBH 4 /alumina is described. The regioselectivity of these reductions were compared with those obtained in solution experiments. [ABSTRACT FROM AUTHOR]

Abstract: A new method for synthesis of alkyl and aryl polyfluoroalkyldithiocarboxylates by reaction of 1,1-dichloropolyfluoroalkylsulfenylchlorides with mercaptans in the presence of ZnCl2 was developed. The sulfenylchlorides are easily obtained by chlorination of benzyl 1,1-dihydropolyfluoroalkylsulfides or benzyl dithioacetals of polyfluoroaldehydes. [Copyright &y& Elsevier]

2-Amino-1,1,3-tricyano-3-bromopropene was obtained from bromination of malononitrile dimer, 2-amino-1,1,3-tricyanopropene with N-bromo-succinimide (NBS). The reactions of this bromo derivative with sodium hydrogen sulfide and thioglycollic acid afforded thiophene and thiopyran derivatives respectively. A novel synthesis of pyridinethione and nicotinonitrile derivatives by using 3-amino-4,4-dicyano-3-butenethioamide as starting material are reported and the synthetic potential of the method is described. [ABSTRACT FROM AUTHOR]

In the present study, a general approach for the synthesis of 1-(1 H -indol-3-yl)-3,3-dimercaptoprop-2-en-1-one (1) and 5-(1 H -indol-3-yl)-3 H -1,2-dithiole-3-thione (2) was performed. They are currently used as efficient precursors for the synthesis of some new compounds bearing five- and/or six-membered heterocyclic moieties, e.g., chromenol (3, 4) , 3,4-dihydroquinoline (7, 8) and thiopyran (10, 12) -based indole core. In addition, molecular docking studies were achieved, which showed that all the newly synthesized compounds are interacting with the active site region of the target enzymes, the targets UDP-N-acetylmuramatel-alanine ligase (MurC), and human lanosterol14α-demethylase, through hydrogen bonds and pi-stacked interactions. Among these docked ligand molecules, the compound ( 9) was found to have the minimum binding energy (-11.5 and -8.5 Kcal/mol) as compared to the standard drug ampicillin (-8.0 and -8.1 Kcal/mol) against the target enzymes UDP-N-acetylmuramatel-alanine ligase (MurC), and Human lanosterol14α-demethylase, respectively. Subsequently, all new synthesized analogues were screened for their antibacterial activities against Gram-positive ( Bacillus subtilis ), and Gram-negative bacteria ( Escherichia coli ), as well as for antifungal activities against Candida albicans and Aspergillus flavus . The obtained data suggest that the compounds exhibited good to excellent activity against bacterial and fungi strains. The compound (E)-2-(6-( 1H -indole-3-carbonyl)-5-thioxotetrahydrothieno [3,2-b]furan-2(3H)-ylidene)-3-( 1H -indol-3-yl)-3-oxopropanedithioic acid (9 ) showed a high binding affinity as well as an excellent biological activity. Therefore, it could serve as the lead for further optimization and to arrive at potential antimicrobial agent., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hassan, Shehadi, Elmaghraby, Mostafa, Zayed and Abdelmonsef.)

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