At 70°C there were added BBr 3 with the injector into a solution of 1-methyl-2-
(4-methoxy-phenyl)-6-methoxy-1-ethylindole in water free methylene
chloride. After 30 min the cold bath was removed and the mixture stirred
overnight. The reaction mixture is carefully poured into a saturated sodium
bicarbonate solution with ice cooling. The product is extracted three times
with ethyl acetate, the combined organic extracts washed with sodium
bicarbonate solution and water, dried and the solvent removed on a rotary
evaporator. The 3-methyl-2-(4-hydroxyphenyl)-6-hydroxy-1-ethylindole was
produced, melting point 142-143°C.
There are added acetic anhydride and of pyridine to the thus obtained 3-
methyl-2-(4-hydroxyphenyl)-6-hydroxy-1-ethylindole and the mixture heated
for 2 h at the boiling point. After cooling the mixture is poured onto ice,
extracted with methylene chloride and the organic phase washed twice with 2
N HCl. After drying and removal of solvent in the rotary evaporator the
residue is chromatographed with methylene chloride via silica and
subsequently 3-methyl-2-(4-acetoxyphenyl)-6-acetoxy-1-ethylindole is
obtained, melting point 150-152°C (recrystallized from ethanol).
