Histamine H3 receptor agents, preparation and therapeutic uses

A compound structurally represented by Formula I

• or a pharmaceutically acceptable salt thereof wherein:
• Q, T, X, and D independently represent carbon or nitrogen, provided that no more than two of Q, T, X, and D are nitrogen;
• R1, R2, and R3 are independently at each occurrence
• —H,
• -halogen,
• —(C1-C7) alkyl,
• —CN,
• —C(O)R7,
• —C(O)(C3-C5)cycloalkyl,
• —C(O)NR7R8,
• —OCF3,
• —OR7,
• —NO2,
• —NR7R8,
• —NR9SO2 R7,
• —NR9C(O)R7,
• —NR9CO2R7,
• —NR9C(O)NR7R8,
• —SR7,
• —SO2R7,
• —SO2CF3,
• —SO2 NR7R8,
• —S(O)R7,
• —O(CH2)mNR7R8,
• -heteroaryl-R9,
• -phenyl-R9,
• provided however that wherein D is nitrogen, then R1 or R2 or R3 are not attached to D, and provided that wherein X is nitrogen, then R1 or R2 or R3 are not attached to X, and provided that wherein T is nitrogen, then R1 or R2 or R3 are not attached to T, and provided that wherein Q is nitrogen, then R1 or R2 or R3 are not attached to Q;
• and further provided that when D and X are carbon, then R1 and R2 can combine to form a 5 or 6 membered ring with D and X,
• wherein the ring so formed may optionally include one double bond in the case of a five membered ring or two double bonds in the case of a six membered ring, and wherein one to three ring atoms may optionally be heteroatoms independently selected from N, O, or S;
• wherein m is 1, 2, 3 or 4;
• R4 and R5 are independently at each occurrence
• —H,
• —OH,
• -halogen,
• —CF2H,
• —CF3,
• —(C1-C3)alkyl,
• —O—(C1-C3) alkyl,
• R6 is independently at each occurrence
• —H,
• -halogen,
• —CF3,
• —(C1-C3) alkyl,
• —NH2,
• —NR7R8,
• —OH,
• —OR7;
• R7 and R8 are independently at each occurrence
• —H,
• —(C1-C6) alkyl,
• Wherein R7 and R8 can combine with the atom to which they are attached to form a 3 to 7 membered ring;
• R9 is independently at each occurrence
• —H,
• —(C1-C3) alkyl,
• provided the compound is not (3-Fluoro-4′-methanesulfonyl-biphenyl-4yl)-[-methyl-pyrrolidin-1-ylmethyl)-pyrrolidin-1-yl]-methanone, or [4-(6-amino-5-hydroxy-pyridin-3-yl) -phenyl]-(2-pyrrolidin-1-ylmethyl-pyrrolidin-1-yl)-methanone.