Pyridizinone derivatives and the use thereof as H3 inhibitors

A compound according to formula I*:

• or a stereoisomeric form, mixture of stereoisomeric forms, or a pharmaceutically acceptable salt thereof;
• wherein:
• X and Xa are each CH;
• Y is S(O)q or O;
• R1 is selected from piperidinyl or pyrrolidinyl optionally substituted with 1 to 3 R20 groups;
• R2 is
• wherein:
• R2 is para to the Y—(CHR4)m—R1group;
• and
• each R3 is:
• independently H, F, Cl, Br, I, OR21, NR23R24, NO2, CN, CF3, C1-C6alkyl, C(═O )R21, CO2R21, or C(═O)NR23R24;
• or
• when R3 is ortho to R2, then R3 and R14 taken together may form —(CH2)s—, —CH2Z—, —ZCH2—, —ZCH2CH2— or CH2CH2Z—;
• wherein Z is O or S(O)y;
• each R4 is independently H or C1-C6alkyl, wherein the alkyl group is optionally substituted with 1 to 3 R20 groups;
• R12 is H, C1-C6alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl, heterocycloalkyl, C(═O)R27, or CO2R27, wherein the alkyl, cycloalkyl, aryl, arylalkyl, heteroaryl, or heterocycloalkyl group is optionally substituted with 1 to 3 R20 groups;
• R13 and R14 are each independently H, C1-C6alkyl, aryl, arylalkyl C1-C6alkoxyl, S(═O)y—C1-C6alkyl, cycloalkyl, heterocycloalkyl, or heteroaryl;
• or R13 and R14, taken together with the carbon atoms through which they are connected form a fused thienyl, pyrrolyl, isoxazolyl, or C3-C6cycloalkyl ring;
• and wherein the fused thienyl, pyrrolyl, isoxazolyl, or cycloalkyl ring is optionally substituted with 1 to 3 R20 groups;
• R20 at each occurrence is independently, H, F, Cl, Br, I, NR23R24, C1-C6 alkyl optionally substituted with OR26, C3-C7cycloalkylC0-C4alkyl, or 3- to 7-membered heterocycloalkylC0-C4alkyl;
• each R23 and R24 is independently selected from H, C1-C6alkyl, and aryl, or R23 and R24, together with the nitrogen atom to which they are attached, form a 3 to 7 membered heterocyclic ring optionally substituted with ═O;
• R26 is H, C1-C6alkyl, aryl, or alkylaryl;
• R27 is H or C1-C6alkyl;
• m is 1, 2, 3, 4, or 5 when R1 is attached via a nitrogen atom, and m is 0, 1, 2, 3, 4, or 5 when R1 is attached via a carbon atom;
• n is 1 or 2;
• q is 0, 1, or 2;
• s is 1, 2, or 3;
• and
• y is 0, 1, or 2;
• provided that:
• (1) when Y is O, n is 2, R3 is H, each R4 is H, m is 2, 3, or 4, and R1 is pyrolidin-1-yl or piperidin-1-yl, then R2 is other than 4,5-dihydro-2H-pyridazin-3-one-6-yl.