The benzoquinolinol derivative (I) is protected as the silyl ether (II) upon treatment with tert-butyldiphenylsilyl chloride and imidazole. Transfer hydrogenolysis of the benzyl ether group of (II) with ammonium formate and Pd/C affords phenol (III). This is then coupled with the trichloroacetimidate of tetraacetylgalactose (IV) in the presence of boron trifluoride etherate to produce the Boc-deprotected galactopyranoside (V). Acylation of (V) with the bis-indolylcarboxylic acid (VI) yields amide (VII).

Desilylation of (VII) employing tetrabutylammonium fluoride on silica gel support gives alcohol (VIII), which is converted into chloride (IX) upon treatment with triphenylphosphine in carbon tetrachloride. Finally, solvolysis of the acetate ester groups with methanolic NaOMe affords the title compound.

The benzoquinolinol derivative (I) is protected as the silyl ether (II) upon treatment with tert-butyldiphenylsilyl chloride and imidazole. Transfer hydrogenolysis of the benzyl ether group of (II) with ammonium formate and Pd/C affords phenol (III). This is then coupled with the trichloroacetimidate of tetraacetylgalactose (IV) in the presence of boron trifluoride etherate to produce the Boc-deprotected galactopyranoside (V). Acylation of (V) with the bis-indolylcarboxylic acid (VI) yields amide (VII).

Desilylation of (VII) employing tetrabutylammonium fluoride on silica gel support gives alcohol (VIII), which is converted into chloride (IX) upon treatment with triphenylphosphine in carbon tetrachloride. Finally, solvolysis of the acetate ester groups with methanolic NaOMe affords the title compound.