Veratrole conversion

Temp. (°C) Conversion (%) Selectivity (%) Guaiacol Selectivity (%) Veratrole Conversion (%) Selectivity (%) Guaiacol Selectivity (%) Veratrole... 

Cyclopropane 87, obtained from n-butyl vinyl ether, rearranges to dihydrofuran 88 only at elevated temperature, and also partly during work-up on silica gel113). The complete conversion of 87 into veratrole by the action of HCl/CH3OH gave rise to the analogous two-step synthesis of hydrourushiol monomethyl ether from l-diazo-3,3-dimethoxy-2-nonadecanone 89113). Ether cleavage of the product yields hydrourushiol, one of the vesicant components of, inter alia, poison ivy. 

Figure 3. Catechol conversion, selectivity to guaiacol and to methylcatechol + veratrol as functions of temperature. Catalyst Al/P/0. Feed catechol and methanol (1/3.4 molar feed ratio).

The activity of 42%STA/silica catalysts for the acylation of related aromatic reactants with iso-butyric anhydride was investigated. In the presence of anisole and veratrole, 100% anhydride conversion was observed, leading to the expected para-acylation products. No reaction was observed in the presence of chlorobenzene and other deactivated aromatic systems. 

Hydrocarbons used in catalytic experiments were obtained by Fluka - ethylbenzene and 1-propylbenzene, and Merck - toluene and 2-propylbenzene. Catalytic experiments were performed in a 50-ml round-bottomed flask equipped with magnetic stirrer and condenser. The initial mixture containing 0.1 g catalyst, 5.0 ml solvent and 2.0 ml substrate was stirred and heated up to the reaction temperature. Then 1.0 ml 30% aqueous solution of hydrogen peroxide (Merck) was added. Small samples (0.1 ml) of the reaction mixture were taken after 1, 2 and 4 h, diluted in 4.0 ml methanol, dried and analysed by GC-MS (Hewlett-Packard). Veratrole was used as internal standard. Hydrogen peroxide conversion was followed by standard iodometric titration. 

Stoichiometric Oxidation of Lignin Model Compounds with Cobalt till) Acetate. In a typical procedure, a solution of DMMP (6.8 mg, 0.018 mmol) and cobalt (III) acetate (84.3%, 10.5 mg, 0.037 mmol) in 18 mL of glacial acetic acid was heated to reflux in 20 min with stirring. One hour later, the color turned from greenish black to pink. The solution was cooled to room temperature and veratrole (10.2 mg, 0.074 mmol) was added as an internal standard for HPLC analysis. A 67% selectivity to DMB at 99% conversion of DMMP was obtained. For reactions where cobalt(III) acetate still remained, an aqueous solution of ferrous sulfate was added dropwise until the color of the solution turned from green to pink then veratrole was added as internal standard. 

Phosphate s BET (m2/g) RX WHSV (h1) Conversion (%) Selectivity guaiacol (%) Selectivity veratrole (%)... 

Selective conversion of a methylenedioxyarene to an o-quinone is a crucial step in a synthesis of phleblarubrone." On the other hand, veratrole derivatives are cleaved to afford hexadienoic esters. ... 

Synthetic pol5oners with pendent carbohydrate moieties, which are referred to as glycopolymers, have potential applications in biomedical techniques [32]. Fukuda et al. reported the synthesis of diblock copolymer LB-9 by the sequential monomer addition technique. The first step was the polymerization of St in bulk with a CuBr/4,4 -di-n-heptyl-2,2 -bipyridine (2dHbpy) complex and 1-phenylethyl bromide as initiator at 110°C. After more than 90% conversion of St, a fresh feed of 3-0-methacrylol-l,2 5,6-di-0-isopropyldiene-D-glucofuranose with CuBr/2dHbpy complex dissolved in veratrole was added in vacuum to the precursor PSt-Br, and then polymerization was performed at 80 °C, forming diblock copolymer LB-9. When LB-9 was treated with formic acid, amphiphilic copolymer LB-10 was obtained [32]. 

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