Biaryl diazabicycloalkane amides as nicotinic acetylcholine agonists

A compound of formula I:

• wherein:
• A is a moiety of formula II:
• D is oxygen or sulfur;
• E is a single bond, oxygen, sulfur, or NR3;
• Ar1 is a 5- or 6-membered aromatic heterocyclic ring having 1, 2 or 3 heteroatoms selected from nitrogen, oxygen or sulfur where not more than one of said heteroatoms is oxygen or sulfur, or
• Ar1 is phenyl;
• Ar2 is a 5- or 6-membered aromatic heterocyclic ring having 1, 2 or 3 heteroatoms selected from nitrogen, oxygen or sulfur where not more than one of said heteroatoms is oxygen or sulfur, or
• Ar2 is phenyl, or
• Ar2 is an 8- or 9-, or 10-membered fused aromatic carbocyclic ring or fused aromatic heterocyclic ring having 1, 2 or 3 heteroatoms selected from nitrogen, oxygen or sulfur where not more than one of said heteroatoms is oxygen or sulfur, or an 8- or 9-, or 10-membered aromatic carbocyclic ring;
• the rings Ar1 and Ar2 are substituted with 0, 1, 2 or 3 substituents selected from:
• halogen, C1-4alkyl, C2-4alkenyl, C2-4alkynyl, CN, NO2, CF3NR1R2, CH2NR1R2, OR2, CH2OR2 or CO2R3;
• R1 and R2 at each occurrence are independently selected from hydrogen, C1-4alkyl, aryl, heteroaryl, C(O)R3, C(O)NHR3, CO2R3 or SO2R3, or
• R1 and R2 in combination is —(CH2)jG(CH2)k— wherein G is oxygen, sulfur, NR3, or a bond;
• a, b and c are each 1 or 2;
• j is 2, 3 or 4;
• k is 0, 1 or 2, and
• R3 at each occurrence is independently selected from hydrogen, C1-4alkyl, aryl, or heteroaryl;
• or a diastereoisomer, enantiomer or pharmaceutically-acceptable salt thereof.