نتایج جستجو برای: Chromane
تعداد نتایج: 58 فیلتر نتایج به سال:
The title compound, C(17)H(13)ClO(2), was obtained from the oxidation of 6-chloro-4-(2-phenyl-ethen-yl)chroman-2-ol, which was synthesized by the reaction of of (E)-3-(5-chloro-2-hy-droxy-phen-yl)acryl-aldehyde with styrylboronic acid using diethyl-amine as a catalyst. The six-membered pyran-one ring of the chromane system has a screw-boat conformation. The dihedral angle between the least-squa...
We were able, for the first time, to synthesize and characterize Pt derivatives with a structural shape similar to vitamin E, having a metalla-chromane core. The formation reaction mechanism includes an unexpected highly selective ortho aromatic electrophilic substitution on phenol, operated by [PtCl(eta(1)-C(2)H(4)OR)(N-N)], R = Me or Ph, and a final cyclization step. The X-ray structure of on...
Synthesis and characterization of resorcinol-acetone copolymer is described. The polymer was prepared by trifluoroacetic acid-catalyzed polymerization of resorcinol with acetone. According to the (1)H-NMR, (13)C-NMR, and MALDI-TOF Mass spectra data, the obtained polymer had three types of repeating units: isopropylidene bridged-resorcinol, chromane ring, and spiro-shaped double chromane ring, i...
By oxidizing alpha tocopherol with chromic anhydride in acetic acid solution, a lactone C21H4002 was obtained. The origin of such a lactone is easily explicable on the theory that alpha tocopherol contains a chromane ring; if alpha tocopherol contained a coumarane ring, a beta hydroxy acid would be expected. Karrer and his co-workers,2 by treating pseudo cumo hydroquinone with phytyl bromide, o...
The reported methodologies for the synthesis of chromane derivatives through the reaction of salicylaldehyde and enolates are discussed. The enolates and their equivalents involved in the reactions discussed in this article were derived from ketones, nitroalkanes, malononitrile and α,β-unsaturated compounds.
An organocatalytic [4 + 2] cascade annulation of salicylaldehydes and 1,3-bisarylsulfonylpropenes has been developed. This protocol enables the efficient straightforward synthesis a new series 3-sulfonyl-2-sulfonylmethyl-2H-chromenes that are useful for exploring pharmacologically valued compounds. Further reductive modifications result in 3-desulfonylated chromene or chromane derivatives. can ...
We screened a collection of synthetic compounds consisting of natural-product-like substructural motifs to identify a spirocyclic chromane as a novel antiplasmodial pharmacophore using an unbiased cell-based assay. The most active spirocyclic compound UCF 201 exhibits a 50% effective concentration (EC50) of 350 nM against the chloroquine-resistant Dd2 strain and a selectivity over 50 using huma...
In the title compound, C(16)H(15)N(3)O(4), the dihedral angle between the chromane and isoxazole rings [r.m.s. deviations = 0.042 and 0.007 Å, respectively] is 20.33 (12)°. The mol-ecular geometry is stabilized by an intra-molecular N-H⋯O hydrogen bond. In the crystal, N-H⋯O hydrogen bonds generate chains along the c-axis direction. The crystal studied was a non-morohedral twin.
The validity of the chromane helicity rule correlating the sense of twist within the dihydropyran ring with the CD sign of the (1)Lb band observed at ca. 290 nm in their electronic circular dichroism (ECD) spectra is examined using a set of natural (S)-trolox derivatives. To investigate both the scope and the limitations of the rule a combination of ECD spectroscopy, especially the temperature ...
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