ENZYMIC PHENOL OXIDATION .3. HEAD TO-HEAD COUPLING OF 1,2,3,4-TETRAHYDRO-7-HYDROXY-1-(4-HYDROXYPHENETHYL)-6-METHOXY-2-METHYLISOQUINOLINE WITH HOMOGENISED WASABIA-JAPONICA MATSUMURA AND HYDROGEN PEROXIDE

Enzymic phenol oxidation of 1,2,3,4-tetrahydro-7-hydroxy-1-(4- hydroxyphenethyl)-6-methoxy-2-methylisoquinoline (I) with homogenised Wasabia japonica Matsumura in the presence of hydrogen peroxide was found to give, by head-to-head. C-O-C coupling, the bisphenethylisoquinoline (IV), characterised as the triacetyl derivative by spectroscopic methods. In contrast, 1,2,3,4-tetrahydro-7-hydroxy-6-methoxy-1-(4-methoxyphenethyl) -2-methylisoquinoline (IX) was recovered almost quantitatively after treatment with Wasabia japonica or potato peel homogenstes. Suggestions are made concerning the active sites of these oxidising enzymes.