Convenient and efficient syntheses of ethyl 4-(3-hydroxy-4-methoxyphenyl)-6, 7-dimethoxy- 2-(1, 2, 4-triazol-1-ylmethyl) quinoline-3-carboxylate (1d) and 10-(3, 4-dimethoxyphenyl)-7, 8- dimethoxy-2H-pyridazino [4, 5-b] quinolin-1-one (1e), metabolites of TAK-603 (1), have been achieved. Use of the methanesulfonyl as a protective group of the phenolic hydroxy for Friedel–Crafts reaction enabled a new simpler synthetic route of 1d in high yield. ...