Ab ismuth(III)b romide-catalysedd irect substitution of benzyla lcohols with arylsulfonylmethyl isocyanides affords sulfinates under mild acidic conditions.A nu nforeseen reversed reactivity was observed in this highly selectivef ormationo f sulfinates instead of the formation of the usually favoured sulfones. Cytotoxicity tests (in vitro)i ndicated that the sulfinates exhibit antibiotic activity against ah uman leukaemia cell line HL-60, which would widen the structural diversity of this antitumour target and confirm the perspectives of further investigations.
A base-promoted direct synthesis of sulfinates from N-sulfonylhydrazones is described. Various N-sulfonylhydrazones, derived from aldehydes and ketones, are converted into the corresponding sulfinates in moderate to good yields. This protocol possesses many advantages such as readily available and stable starting materials, broad substrate scope, and metal-free reaction conditions.
Sulfuric-acid-promoted tandem reaction of phenols with acetophenones under solvent- and metal-free conditions has been developed, which afforded functional 4H-chromenes in good yields with water as the side product.
4H-Chromene-2-carboxylic acid ester derivatives of renieramycin M might be of use for the structural-activity relationship studies of antitumor antibiotic tetrahydroisoquinoline natural products. Accordingly, 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic acid, one key intermediate, was synthesized via the condensation of (3E)-2-oxo-4-phenylbut-3-enoate methyl ester with 4-tert-butylphenol in the presence of AuCl3/3AgOTf (5 mol%), followed by cyclodehydration and aqueous hydrolysis. The product was unambiguously shown to the 4H-chromene-2-carboxylic acid by spectroscopy and X-ray crystallographic analysis. A packing diagram of the crystal structure shows that aromaticπ-stacking interactions and O–H⋯O hydrogen bond stabilize the structure in the solid.
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