A compound as represented by formula (I), and optical isomers, solvates, pharmaceutically-acceptable salts, or prodrugs thereof. The present invention has urate transporter 1 (URAT1) inhibitory activity, can be used for treatment of gout and hyperuricemia, and can also be used for treatment of diseases related to abnormal URAT1 activity, such as recurrent gout attacks, gouty arthritis, hypertension, cardiovascular diseases, coronary heart disease, Lesch-Nyhan syndrome, Kearns-Sayre syndrome, kidney diseases, kidney stones, kidney failure, joint inflammations, arthritis, urolithiasis, lead poisoning, hyperparathyroidism, psoriasis, sarcoidosis, or hypoxanthine-guanine phosphoribosyltransferase deficiency. (I)