Substituted pyridine compounds useful for controlling chemical synaptic transmission

A compound of the structure

• 10
• wherein n is an integer of 1 to 4;
• R1 and R2 are independently selected from the group consisting of hydrogen, lower alkyl, alkenyl, alkynyl, aralkyl and cyanomethyl;
• R3, at each occurence, is selected from the group consisting of hydrogen, haloalkyl and lower alkyl;
• R4, at each occurrence, is independently selected from the group consisting of hydrogen, hydroxyl, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, alkenoxy, alkynioxy, thioalkoxy, aliphatic acyl, —CF3, nito cyano, —N(C1-C3 alkyl)-C(O)(C1-C3 alkyl), —C1-C3 alkylamino, alkenylamino, alkynylamino, di(C1-C3 alkyl) amino, amino, halogen, —C(O)O—(C1-C3 alkyl), —C(O)NH—(C1-C3 alkyl), —C(O)N(C1-C3 alkyl)2, haloalkyl, alkoxylcarbonyl, alkoxyalkoxy, carboxaldehyde, carboxamide, cycloalkyl, cycloalkenyl, aliphatic acyl, —CH═NOH, —PO3H2, —OPO3H2, heterocyclylalkyl, cycloalkynyl, aryl, aroyl, aryloxy, arylamino, biaryl, thioaryl, heterocyclyl, heterocycloyl, alkylaryl, aralkyl, aralkenyl, alkylheterocyclyl, sulfonyl, sulfonamido, carbamate, aryloxyalkyl, carboxyl and —C(O)NH(benzyl);
• R5 is selected from the group consisting of hydrogen, halogen, lower alkyl, nitro, lower alkylamino and lower alkoxy;
• R6 is selected from the group consisting of hydrogen, halogen, hydroxyl, lower alkyl, lower alkenyl, lower alkynyl, lower alkoxy, alkenoxy, alkynoxy, thioalkoxy, aliphatic acyl, —CF3, nitro, amino, cyano, —N(C1-C3 alkyl)—C(O)(C1-C3 alkyl), —C1-C3 alkylamino, alkenylamino, alkynylamino, di(C1-C3 alkyl)amino, —C(O)O—(C1-C3 alkyl), —C(O)NH—(C1-C, alkyl), —CH═NOH, —C(O)N(C1-C3 alkyl)2, haloalkyl, alkoxylcarbonyl, alkoxyalkoxy, carboxaldehyde, carboxamide, cycloalkyl, cycloalkenyl, aliphatic acyl, —CH═NOH, —PO3H2, —OPO3H2, heterocyclylalkyl, cycloalkynyl, aryl, aroyl, aryloxy, arylamino, biaryl, thioaryl, heterocyclyl, heterocycloyl, alkylaryl, aralkenyl, aralkyl, alkylheterocyclyl, sulfonyl, sulfonamido, carbamate, aryloxyalkyl, carboxyl and —C(O)NH(benzyl);
• and
• A is selected from the group consisting of —O—, —S—, —N(R1)—, —SO2N(R1)— and —NR1SO2—;
• wherein R1, R2, R3, R4, R5 and R6 are unsubstituted or substituted with at least one electron donating or electron withdrawing group;
• and pharmaceutically acceptable salts thereof;
• with the proviso that when A=O at least one of R5 or R6 is halogen;
• and with the further proviso that when R3 and R4 are attached to a carbon which is alpha to a heteroatom, R4 is not halogen, hydroxyl or amino.