Abstract: Disclosed herein are compound or pharmaceutically acceptable salts or stereoisomers thereof of formula I: X1 is linear or branched C1-6 alkyl, C3-8 cycloalkyl, C6-10 aryl, 5-10 membered heteroaryl, 4-8 membered heterocycloalkyl, wherein X1 is unsubstituted or substituted with one or more of halogen, linear or branched C1-6 alkyl, linear or branched C1-6 heteroalkyl, CF3, CHF2, CMeF2, —O—CHF2, —O—(CH2)2—OMe, OCF3, C1-6 alkylamino, —CN, —N(H)C(O)—C1-6alkyl, —OC(O)—C1-6alkyl, —OC(O)—C1-4alkylamino, —C(O)O—C1-6alkyl, —COOH, —C1-6alkylC(O)OH, —C1-6alkylC(O)O—C1-6alkyl, NH2, C1-4 alkoxy, C1-4 alkylhydroxy, —CH2F, —N(H)C(O)—O—C1-6 alkyl, and C(OH)(CF3); or X1 together with the N atom of the carbamate forms a 4-8 membered heterocycloalkyl, which is unsubstituted or substituted with one or more of halogen, linear or branched —C1-6 alkyl, CF3, CHF2, CMeF2, —O—(CH2)2—OMe, OCF3, OCHF2, C1-6 alkylamino, —CN, —N(H)C(O)—C1-6alkyl, —OC(O)—C1-6alkyl, —C(O)O—C1-6alkyl, —COOH, —C1-6alkylC(O)OH, —C1-6alkylC(O)O—C1-6alkyl, NH