4,7-dihydroxy-2-(4-methoxy-phenyl)-thieno[2,3-c]pyridine-5-carboxylic acid butyl ester 、 4,7-dihydroxy-2-(4-methoxy-phenyl)-thieno[3,2-c]pyridine-6-carboxylic acid butyl ester 、 生成 {[4-hydroxy-2-(4-methoxy-phenyl)-thieno[2,3-c]pyridine-5-carbonyl]-amino}-acetic acid