Notes - Studies on 3-Acylcatechols

Awad, W. I.; El-Neweihy, M. F.; Selim, Sultan

doi:10.1021/jo01105a606

Cited by 8 publications

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“…The ketones 5/6 -H 2 were obtained by addition of organolithium or Grignard reagents to 2,3-dimethoxybenzaldehyde, followed by Jones oxidation and subsequent BBr 3 cleavage of the methyl ethers . The initially prepared secondary alcohols were oxidized without purification 1 Preparation of the Ligands 5 − 7 -H 2 …”

Section: Resultsmentioning

confidence: 99%

“…General Procedure for the Addition of Grignard Reagents to 2,3-Dimethoxybenzaldehyde. A few drops of the bromide are added to the magnesium (0.01 mol) in a small amount of ether. After the reaction has started, the remaining bromide (in total 0.01 mol) is dissolved in ether (10 mL) and added.…”

Section: Methodsmentioning

confidence: 99%

“…1-(2,3-Dimethoxyphenyl)-1-butanol. Yield: 1.4 g (82%) of crude product, colorless liquid. 1 H NMR (CDCl 3 , 400 MHz): δ (ppm) = 7.03 (t, J = 8.0 Hz, 1 H), 6.94 (dd, J = 8.0, 1.6 Hz, 1 H), 6.83 (dd, J = 8.0, 1.6 Hz, 1 H), 4.92 (dd, J = 8.0, 5.5 Hz, 1 H), 3.86 (s, 3 H), 3.85 (s, 3 H), 1.77 (m, 1 H), 1.68 (m, 1 H), 1.47 (m, 1 H), 1.34 (m, 1 H), 0.93 (t, J = 7.4 Hz, 3 H).…”

Section: Methodsmentioning

confidence: 99%

“…(2,3-Dimethoxyphenyl)ethyl Ketone. Yield: 120 mg (8.5%) and 0.47 g of crude product, which is purified by chromatography (ethyl acetate/hexane 1:10), colorless oil. 1 H NMR (CDCl 3 , 400 MHz): δ (ppm) = 7.14 (dd, J = 7.7, 1.6 Hz, 1 H), 7.08 (t, J = 7.7 Hz, 1 H), 7.02 (dd, J = 7.7, 1.6 Hz, 1 H), 3.89 (s, 3 H), 3.88 (s, 3 H), 2.98 (q, J = 7.1 Hz, 2 H), 1.18 (t, J = 7.1 Hz, 3 H).…”

Section: Methodsmentioning

confidence: 99%

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Hierarchical Assembly of Helicate-Type Dinuclear Titanium(IV) Complexes

et al. 2005

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The ligands 4-7-H(2) were used in coordination studies with titanium(IV) and gallium(III) ions to obtain dimeric complexes Li(4)[(4-7)(6)Ti(2)] and Li(6)[(4/5a)(6)Ga(2)]. The X-ray crystal structures of Li(4)[(4)(6)Ti(2)], Li(4)[(5b)(6)Ti(2)], and Li(4)[(7a)(6)Ti(2)] could be obtained. While these complexes are triply lithium-bridged dimers in the solid state, a monomer/dimer equilibrium is observed in solution by NMR spectroscopy and ESI FT-ICR MS. The stability of the dimer is enhanced by high negative charges (Ti(IV) versus Ga(III)) of the monomers, when the carbonyl units are good donors (aldehydes versus ketones and esters), when the solvent does not efficiently solvate the bridging lithium ions (DMSO versus acetone), and when sterical hindrance is minimized (methyl versus primary and secondary carbon substituents). The dimer is thermodynamically favored by enthalpy as well as entropy. ESI FT-ICR mass spectrometry provides detailed insight into the mechanisms with which monomeric triscatecholate complexes as well as single catechol ligands exchange in the dimers. Tandem mass spectrometric experiments in the gas phase show the dimers to decompose either in a symmetric (Ti) or in an unsymmetric (Ga) fashion when collisionally activated. The differences between the Ti and Ga complexes can be attributed to different electronic properties and a charge-controlled reactivity of the ions in the gas phase. The complexes represent an excellent example for hierarchical self-assembly, in which two different noncovalent interactions of well balanced strengths bring together eleven individual components into one well-defined aggregate.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Hierarchical Assembly of Helicate-Type Dinuclear Titanium(IV) Complexes

et al. 2005

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“…íl-Keto-12-methylene-9.10dihydro-9,10-ethanoanthracene (IV). A solution of crude ketol (III) (0.455 g., 1.82 mmoles) and p-toluenesulfonyl chloride (0.380 g., 1.99 mmoles) in dry pyridine (4 ml.) was kept at room temperature for 40 hr.…”

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confidence: 99%