Veratryl alcohol 3,4-dimethoxybenzyl

Another iron porphyrin complex with 5,10,15,20-tetrakis(2, 6 -dichloro-3 -sulfonatophenyl)porphyrin was applied in ionic liquids and oxidized veratryl alcohol (3,4-dimethoxybenzyl alcohol) with hydrogen peroxide in yields up to 83% to the aldehyde as the major product [145]. In addition, TEMPO was incorporated via... 

LiP catalyzes the oxidation of 3,4-dimethoxybenzyl alcohol (veratryl alcohol) to veratryl aldehyde. Since this reaction can be easily followed at 310 nm, it is the basis for the standard assay for this enzyme (26,27). The enzyme exhibits normal saturation kinetics for both veratryl alcohol and H202 (28,43). Steady-state kinetic results Indicate a ping-pong mechanism in which H202 first oxidizes the enzyme and the oxidized intermediate reacts with veratryl alcohol (43). The enzyme has an extremely low pH optimum ( 2.5) for a peroxidase (43,44) however, the rate of formation of compound I (kx, Fig. 2) exhibits no pH dependence from 3.0-7.0 (45,46). Addition of excess veratryl alcohol at pH 3.0 results in the rapid conversion of... 

Analogous behavior is also observed with the corresponding 3,4-dimethoxy derivatives [102] with these derivatives, however, because of the increased stability of the radical cations, in acidic solution a decrease in reactivity of three orders of magnitude for the deprotonation reaction is observed on going from MBA to the 3,4-dimethoxybenzyl alcohol radical cation (veratryl alcohol, VA). In the presence of OH the deprotonation site shifts from carbon to oxygen, as previously described for the 4-methoxy derivatives, and a dramatic increase in reactivity is observed, VA + reacting with OH with A = 1.3 x 10 M s (Table 5), a value which is lower than the diffusion limit and which, compared with that measured for MBA +, rather than the decreased O-H acidity of VA , presumably reflects the increased electron density on the aromatic system which disfavors the intramolecular (side-chain to nucleus) electron transfer eventually leading to the benzyloxyl radical. 

Biomimetic oxidation of 3,4-dimethoxybenzyl alcohol (veratryl alcohol), with HjOj in the presence of catalytic amounts of iron(III) porphyrin complex (ClgTAPS FeCl) and/or horseradish peroxidase (HRP) in [bmim][PEg], was studied by Kumar et al. (Scheme 14.6) [6]. Comparison of the obtained results showed better catalytic activity for iron complex. 

An aryl-alcohol oxidase produced optimally under carbon limitation from Bjerkandera adusta oxidized a number of benzyl alcohols including 4-methoxybenzyl alcohol, 3,4-dimethoxybenzyl alcohol (veratryl alcohol), and 4-hydroxy-3-methoxybenzyl alcohol, with the production of H202 from 02 monosaccharides were not oxidized (Muheim et al. 1990). An aryl-alcohol oxidase from Pleurotus eryngii is a flavoprotein with range of substrates comparable to that from B. adusta (Guillen et al. 1992). 

---