Intermediate useful for synthesis of SGLT inhibitor and method for preparing SGLT inhibitor using same

A method for preparing a compound of the following Chemical Formula 5, comprising:

• subjecting a compound of the following Chemical Formula 4 to deprotection and ring-opening reactions under an acidic condition in the presence of water to obtain the compound of Chemical Formula 5:
• wherein
• n is 1 or 2,
• X is a halogen,
• PG is a protecting group,
• B is
• wherein Ra, Rb, Rc, and Rd are each independently hydrogen, a halogen, hydroxy, mercapto, cyano, nitro, amino, carboxy, oxo, a C1-7 alkyl, a C1-7 alkylthio, a C2-7 alkenyl, a C2-7 alkynyl, a C1-7 alkoxy, a C1-7 alkoxy-C1-7 alkyl, a C2-7 alkenyl-C1-7 alkyloxy, a C2-7 alkynyl-C1-7 alkyloxy, a C3-10 cycloalkyl, a C3-7 cycloalkylthio, a C5-10 cycloalkenyl, a C3-10 cycloalkyloxy, a C3-10 cycloalkyloxy-C1-7 alkoxy, a phenyl-C1-7 alkyl, a C1-7 alkylthio-phenyl, a phenyl-C1-7 alkoxy, a mono- or di-C1-7 alkylamino, a mono- or di-C1-7 alkylamino-C1-7 alkyl, a C1-7 alkanoyl, a C1-7 alkanoylamino, a C1-7 alkylcarbonyl, a C1-7 alkoxycarbonyl, carbamoyl, a mono- or di-C1-7 alkylcarbamoyl, a C1-7 alkylsulfonylamino, phenylsulfonylamino, a C1-7 alkylsulfinyl, a C6-14 arylsulfanyl, a C6-14 arylsulfonyl, a C6-14 aryl, a 5- to 13-membered heteroaryl, a 5- to 10-membered heterocycloalkyl, a 5- to 10-membered heterocycloalkyl-C1-7 alkyl, or a 5- to 10-membered heterocycloalkyl-C1-7 alkoxy;
• the ring C is a C3-10 cycloalkyl, a C5-10 cycloalkenyl, a C6-14 aryl, a 5- to 13-membered heteroaryl, or a 5- to 10-membered heterocycloalkyl;
• the alkyl, the alkenyl, the alkynyl, and the alkoxy are each independently unsubstituted, or have one or more substituents selected from the group consisting of a halogen, hydroxy, cyano, nitro, amino, mercapto, a C1-7 alkyl, and a C2-7 alkynyl;
• the cycloalkyl, the cycloalkenyl, the aryl, the heteroaryl, and the heterocycloalkyl are each independently unsubstituted, or have one or more substituents selected from the group consisting of a halogen, hydroxy, cyano, nitro, amino, mercapto, a C1-4 alkyl, and a C1-4 alkoxy;
• and
• the heteroaryl and the heterocycloalkyl each independently contain one or more heteroatoms selected from the group consisting of N, S, and O.