ChemInform Abstract: Versatile Route to Functionalized 1H-2-Benzothiopyrans and 1H-2-Naphthothiopyrans by Electrophilic Cyclization of Bis(arylmethylthio)acetylenes: 2-Benzo- and 2-Naphthothiopyrylium Salts (original) (raw)
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Journal of Heterocyclic Chemistry, 1978
Synthesis of 5,6‐dihydro‐2H‐lhiopyrans by mild dehydromesylation of the corresponding tetrahydro‐4H‐thiopyran‐4‐mesylates using commercial grade Woelrn W‐200 (activity, Super 1) neutral alumina is described. Cis‐ and trans‐stereoisomers of 2,6‐diphenyl‐5,6‐dihydro‐2H‐thiopyrans were prepared for the first lime without isomerization.
Zeitschrift für Naturforschung B, 2017
A selected set of new 4H-benzothiopyran-4-one derivatives 6a-h has been prepared by a one-pot reaction involving deprotonated methyl 3-oxo-3(2′,4′,5′trichlorophenyl)propanoate 5 and the appropriate aryl or alkyl isothiocyanate. 2,4,5-Trichloroacetophenone 4, required for the synthesis of 5, is successfully prepared by Friedel-Craft's acetylation of 1,2,4-trichlorobenzene in 82% yield. The structures of the new compounds 5 and 6a-h are based on microanalytical and spectral (NMR, MS(EI), and HRMS) data.
International Journal of Advanced Research in Chemical Science
An efficient approach for the synthesis of functionalized tetrahydro-4H-chromenes 3a-c and tetrahydro-4H-thiopyran 3d-e derivatives moderate to high yields have been achieved via a addition-cyclization reaction of α, β-Unsaturated cyanoesters 1a-c with dimedone 2p or 1, 3-cyclohexandione 2q in presence of sodium ethoxide and Benzaldehyde with 2-propanol in presence of ammonium sulphide respectively. This methodology differs from the previous classical methods in its simplicity and ready availability of the catalyst. The structures of the compounds 3a-e were confirmed by their ultraviolet, infrared, 1 H NMR, 13 C NMR and elemental analyses.
Synthesis of 3-cyano-Δ2- and -Δ3-dihydro-pyran and -thiopyran derivatives
Carbohydrate Research, 1986
Treatment of trans,trans-3,5-diacyloxy-r-4-tert-butoxycarbonyl-4-cyano-tetrahydropyran (1a–b) and -tetrahydrothiopyran (1c–d), 5-(2,4-di-O-acyl-3-tert-butoxycarbonyl-3-cyano-3-deoxy-β-d-xylo-pentopyranosyl)-3-ethoxycarbonyl-2-methylfuran (2a–b) and -3-acetyl-2-methylfuran (2c–d), and methyl 2,4,6-tri-O-acetyl-3-tert-butoxycarbonyl-3-cyano-3-deoxy-α-d-gluco-hexopyranoside (3) with toluene-p-sulfonic acid in acetic anhydride gave the corresponding branched unsaturated compounds, 5-acyl-4-cyano-5,6-dihydro-2H-pyran (4a–b) and -thiopyran (4c–d), 5-(4-O-acyl-3-cyano-2,3-dideoxy-β-d-glycero-pent-2-enopyranosyl)-furans (5a–d) (minor), 5-(2-O-acyl-3-cyano-3,4-dideoxy-β-d-glycero-pent-3-enopyranosyl)furans (6a–d) (major), and methyl 2,6-di-O-acetyl-3-cyano-3,4-dideoxy-α-d-erythro-hex-3-enopyranoside (7).