The fungal laccases catalyzed oxidation of 1-(3,4-dimethoxyphenyl)-1-propen
e (2) with dioxygen in acetate buffer (pH 4.5) producing 1 -(3,4-dimethoxyp
henyI)propane- 1,2-diol (4) and its 1-O-acetyl and 2-O-acetyl derivatives 5
and 6, and 3,4-dimethoxybenzaldehyde (7). However, in phosphate buffer (pH
5.9), the same reaction produced only 4 and 7. When 4 was treated in the s
ame fashion in the phosphate buffer, it was converted into 7 with more than
95 mol% yield. This, together with the formation of 5 and 6 in the acetate
buffer, showed that 2 is converted into 3-5 via 1-(3,4-dimethoxyphenyl)pro
pane-1,2-epoxide (3) in the acetate buffer in the presence of ABTS. The maj
or reaction of fungal laccase-catalyzed oxidation of 2 with dioxygen in the
presence of ABTS is epoxidation of the double bond conjugated to the aroma
tic ring. (C) 2000 Elsevier Science B.V. All rights reserved.