- A Double-Walled Knotted Cage for Guest-Adaptive Molecular Recognition
-
We synthesized a double-walled knotted cage from a flexible tripodal ligand. The characteristic double-walled structure provided a unique adaptive behavior of the cavity upon inclusion of organic molecules, which was evidenced by NMR and X-ray measurement
- Fujita, Makoto,Takezawa, Hiroki,Tamura, Yukari
-
supporting information
p. 5504 - 5508
(2020/04/10)
-
- Catalytic Halogenation of Selected Organic Compounds Mimicking Vanadate-dependent Marine Metalloenzymes
-
The ammonium metavanadate, mimicking vanadate-dependent metalloenzymes, efficiently catalyses the halogenation of a variety of organic substrates in dilute conditions in moderate to good yields using dilute hydrogen peroxide (30percent) as an oxidizing agent exhibiting remarkable ortho selectivity with electron-rich aromatics.
- Dinesh, Chimmanamada U.,Kumar, Rajiv,Pandey, Bipin,Kumar, Pradeep
-
p. 611 - 612
(2007/10/02)
-
- Bromophloroglucinols and their methyl ethers
-
All 16 bromination products of phloroglucinol and its methyl ethers, as well as five bromoresorcinols and three of their dimethyl ethers, were synthesized and analyzed by nuclear magnetic resonance spectroscopy.Two or three equivalents of bromine convert phloroglucinol to di- and tribromophloroglucinol, 5-methoxyresorcinol to the tri- and 2,4-dibromo, 3,5-dimethoxyphenol to the tri- and 2,6-dibromo, and 1,3,5-trimethoxybenzene to the dibromo compound.With one equivalent of bromine, 3,5-dimethoxyphenol reacts preferentially at C-2 while 5-methoxyresorcinol gives both monobromo isomers.Partial debromination with sodium sulfite yields successively 2,4-dibromo- and 2-bromo-5-methoxyresorcinol from the tribromo compound but fails with brominated 3,5-dimethoxyphenol.In the resorcinol series, C-2 is invariably the least reactive position. 4,6-Dibromo-5-methoxyresorcinol and 2,4-dibromo-3,5-dimethoxyphenol are accessible by methylation of dibromophloroglucinol, obtained from 3,5-dibromo-2,4,6-trihydroxybenzoic acid by decarboxylation.In contrast to resorcinol and tribromoresorcinol, the partial bromination of pholoroglucinol and debromination of tribromopholoroglucinol are not selective.The 13Cnmr spectra of bromophloroglucinol methyl ethers show characteristic downfield shifts for methoxy groups orthogonal to the aromatic ring plane.
- Kiehlmann, E.,Lauener, R. W.
-
p. 335 - 344
(2007/10/02)
-
- A GENERAL PROCEDURE FOR THE SYNTHESIS OF METHYLTHIO-, METHYLSELENO- AND METHYLTELLURO-SUBSTITUTED AROMATIC COMPOUNDS
-
A one-pot procedure is described which allows the facile introduction of one or two methylchalcogeno groups into a variety of monobromo or dibromo aromatics.The bromo compounds were converted to their corresponding lithio derivatives by treatment with t-butyllithium in tetrahydrofuran at -78 deg C, and these derivatives were then treated, at ambient temperature with elemental sulfur, selenium, or tellurium.The resulting lithium thiolates, selenolates and tellurolates were finally methylated with methyl iodide to afford good yields (typically 50-80percent) of the various methylchalcogeno-substituted aromatic compounds.The procedure could not be used for the synthesis of ortho-disubstituted compounds, or for the simultaneous introduction of three methylchalcogeno groups.
- Engman, Lars,Hellberg, Jonas S. E.
-
p. 357 - 366
(2007/10/02)
-