Electrochemical and IR spectroscopic detection of oxidation products of the monomer and dimer of vanillyl alcohol in a sol–gel processed silicate matrix

Roźniecka, Ewa; Zawisza, Izabella; Jawiczuk, Magdalena; Branowska, Danuta; Opałło, Marcin

doi:10.1016/j.jelechem.2010.04.020

Cited by 5 publications

(6 citation statements)

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“…11 Compounds 3 and 6 were synthesized using modified literature procedures as summarised in Scheme 1. [25][26][27] Reaction of acetovanillone with benzoyl chloride, pyridine and Br 2 in CHCl 3 gives 4-benzoyl-3-methoxy-bromoacetylbenzene (10) which with guaiacol and K 2 CO 3 in acetone produces 11. Treatment of 11 with NaOH and NaBH 4 in THF/H 2 O yields 3 directly, whereas treatment with just NaOH yields 6; in both cases, the NaOH converts the protecting OBz group to OH.…”

Section: Synthesis Of Lignin Modelsmentioning

confidence: 99%

“…13 4-Benzoyl-3-methoxy-bromoacetylbenzene (10). 25,27 Benzoyl chloride (19 g, 0.14 mol) and pyridine (11 g, 0.14 mol) were added drop-wise to a stirred reaction mixture of acetovanillone (20 g, 0.12 mol) in CHCl 3 (100 mL) at r.t. After 1 h, the solvent was removed and the residue was extracted with EtOAc (2 × 100 mL). This solvent was then removed, and the residue was dissolved in CHCl 3 (100 mL).…”

Section: Literature Reported Compoundsmentioning

confidence: 99%

“…1-(4-Benzoyl-3-methoxyphenyl )-2-(2-methoxyphenoxy)ethanone (11). 25,27 Guaiacol (2.2 g, 18 mmol) was added dropwise to a stirred acetone solution (150 mL) of K 2 CO 3 (2.5 g, 18 mmol) and 10 (5.0 g, 14 mmol) at r.t. After 16 h, the solid was filtered off, and the filtrate was evaporated to give a residue that was loaded onto a silica gel column; hexanes-EtOAc (7 : 3) was used as elutant. The appropriate fractions were collected and evaporated to yield a white powder that was washed with hexanes-EtOAc (7 : 3, 2 × 20 mL) and then dried in vacuo.…”

Section: Literature Reported Compoundsmentioning

confidence: 99%

“…23, 25 (3). 27 NaBH 4 (0.32 g, 8.5 mmol) was added over 5 min to a stirred mixture of NaOH (3.0 g, 75 mmol) and 11 (1.5 g, 3.8 mmol) in THF/H 2 O (50 mL/50 mL) at r.t. After 16 h, aq. NH 4 Cl (100 mL) and THF (50 mL) were added; the organic layer was collected, and the aq.…”

Section: Literature Reported Compoundsmentioning

confidence: 99%

“…25,27 13 C{ 1 H} NMR (100 MHz, CDCl 3 ): δ 30.69 (CH 2 Br), 56.29 (OCH 3 ), 112.52, 122.54, 123.35, 128.77, 128.95, 130.52, 132.84, 133.98, 144.95, 152.09, 164.28 (OvC-O), 190.42 (OvCCH 2 ). ESI/MS + : 371 [M + Na] + .…”

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confidence: 99%

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Hydrogenolysis of β-O-4 lignin model dimers by a ruthenium-xantphos catalyst

et al. 2012

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Hydrogenolysis reactions of so-called lignin model dimers using a Ru-xantphos catalyst are presented (xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene). For example, of some nine models studied, the alcohol, 2-(2-methoxyphenoxy)-1-phenylethanol (1), with 5 mol% Ru(H)(2)(CO)(PPh(3))(xantphos) (18) in toluene-d(8) at 135 °C for 20 h under N(2), gives in ~95% yield the C-O cleavage hydrogenolysis products, acetophenone (14) and guaiacol (17), and a small amount (<5%) of the ketone, 2-(2-methoxyphenoxy)-1-phenylethanone (4), as observed by (1)H NMR spectroscopy. The in situ Ru(H)(2)(CO)(PPh(3))(3)/xantphos system gives similar findings, confirming a recent report (J. M. Nichols et al., J. Am. Chem. Soc., 2010, 132, 12554). The active catalyst is formulated 'for convenience' as 'Ru(CO)(xantphos)'. The hydrogenolysis mechanism proceeds by initial dehydrogenation to give the ketone 4, which then undergoes hydrogenolysis of the C-O bond to give 14 and 17. Hydrogenolysis of 4 to 14 and 17 also occurs using the Ru catalyst under 1 atm H(2); in contrast, use of 3-hydroxy-2-(2-methoxyphenoxy)-1-phenyl-1-propanone (7), for example, where the CH(2) of 4 has been changed to CHCH(2)OH, gives a low yield (≤15%) of hydrogenolysis products. Similarly, the diol substrate, 2-(2-methoxyphenoxy)-1-phenyl-1,3-propanediol (9), gives low yields of hydrogenolysis products. These low yields are due to formation of the catalytically inactive complexes Ru(CO)(xantphos)[C(O)C(OC(6)H(4)OMe)=C(Ph)O] (20) and/or Ru(CO)(xantphos)[C(O)CH=C(Ph)O] (21), where the organic fragments result from dehydrogenation of CH(2)OH moieties in 7 and 9. Trace amounts of Ru(CO)(xantphos)(OC(6)H(4)O), a catecholate complex, are isolated from the reaction of 18 with 1. Improved syntheses of 18 and lignin models are also presented.

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