合成路线1

Condensation of 5-bromoindole (I) with oxalyl chloride produced (5-bromo-3-indolyl)glyoxyl chloride (II), which was subsequently treated with dimethylamine to give amide (III). Conversion of (III) to the tributylstannyl derivative (IV) was achieved by reaction with hexabutylditin in the presence of tetrakis(triphenylphosphine) palladium in refluxing dimethoxyethane. Palladium-catalyzed coupling of stannyl indole (IV) with 5-bromo-2-thiophenecarboxaldehyde (V) furnished the thienyl indole (VI). Finally, reduction of (VI) with LiAlH4 in boiling THF produced a mixture of the desired 5-methylthiophene derivative along with the 5-(hydroxymethyl) analogue (VII), that were separated by column chromatography.