A compound of formula I: ** Formula ** or a pharmaceutically acceptable salt thereof, wherein: m is from 0 to 3; X is: -NRa-; and Ra is hydrogen or C1-6 alkyl; R1 is: C1-6 alkyl; C2-6 alkenyl; C2-6 alkynyl; C1-6 haloalkyl; C1-6 alkoxy-C1-6 alkyl; C2-6 hydroxyalkenyl; C1-6 aminoalkyl; C1-6 alkylsulfonyl-C1-6 alkyl; C3-6 cycloalkyl optionally substituted with C1-6 alkyl; C3-6 cycloalkyl-C1-6 alkyl, wherein the C3-6 cycloalkyl portion is optionally substituted with C1-6 alkyl; tetrahydrofuranyl; C1-6 tetrahydrofuranylalkyl; oxetanyl; or oxetanalkyl C1-6; or R1 and Ra together with the atoms to which they are attached form a three to six membered ring that may optionally include an additional heteroatom selected from O, N and S, and which is substituted with oxo, halo or C1-6 alkyl; R2 is: halo; C1-6 alkoxy; cyano; C2-6 alkynyl; C2-6 alkenyl; C1-6 haloalkyl; C1-6 haloalkoxy; C3-6 cycloalkyl, wherein the C3-6 cycloalkyl portion is optionally substituted with C1-6 alkyl; C3-6 cycloalkyl-C1-6 alkyl, wherein the C3-6 cycloalkyl portion is optionally substituted with C1-6 alkyl; tetrahydrofuranyl; C1-6 tetrahydrofuranylalkyl; acetyl; oxetanyl; or oxetanalkyl C1-6; R3 is: -OR4; halo; cyano; C1-6 alkyl; C1-6 haloalkyl; C3-6 cycloalkyl optionally substituted with C1-6 alkyl; C3-6 cycloalkyl-C1-6 alkyl, wherein the C3-6 cycloalkyl portion is optionally substituted with C1-6 alkyl; tetrahydrofuranyl; tetrahydrofuranyl-C 1-6 alkyl; oxetanyl; or oxetanalkyl C1-6; R4 is: C1-6 alkyl; C1-6 haloalkyl; C1-6 alkoxy-C1-6 alkyl; C3-6 cycloalkyl optionally substituted with C1-6 alkyl or halo; C3-6 cycloalkyl-C1-6 alkyl, wherein the C3-6 cycloalkyl portion is optionally substituted with C1-6 alkyl or halo; tetrahydrofuranyl; C1-6 tetrahydrofuranylalkyl; oxetanyl; or oxetanalkyl C1-6; R5 is hydrogen; or C1-6 alkyl; n is 0 or 1; R6 is hydrogen; C1-6 alkyl; C1-6 alkoxy-C1-6 alkyl; C1-6 hydroxyalkyl; C1-6 aminoalkyl; C3-6 cycloalkyl; C3-6 cycloalkyl-C1-6 alkyl; heterocyclyl; or C1-6 heterocyclyl