Compound for treating metabolic diseases and preparation method and use thereof

A compound as shown in Formula (I), or

• a racemate, a stereoisomer, a geometric isomer, a tautomer, or a pharmaceutically acceptable salt thereof:
• wherein,
• R1 is hydrogen, substituted or unsubstituted alkyl or halogen;
• each of the R2 is independently selected from the group consisting of substituted or unsubstituted alkyl, halogen, hydroxyl, nitro, cyano, sulphonic acid group and carboxyl;
• m is 0, 1, 2, 3 or 4;
• each of the R3 is independently selected from the group consisting of substituted or unsubstituted alkyl, halogen, hydroxyl and aryl;
• and
• n is 0, 1, 2, 3 or 4.