| abstract |
A compound of structural formula IIIa that is radioactively labeled with 11C, 18F, 15O, or 13N: ** Formula ** where Ar is selected from the group consisting of (1) phenyl, (2) indole, (3) indazole, or ( 4) biphenyl, where each is optionally substituted with 1 to 3 groups of Ra; Ra is selected from the group consisting of (1) halogen, (2) hydroxyl, (3) C1-6 alkyl, which is unsubstituted or substituted by one or more halogens, (4) C3-6 cycloalkyl, (5) -NR2C (O) R2, (6) -C (O) N (R2) 2, (7) -C (R2) 2RO2, (8) -C (O) R2, (9) -NO2, (10) -CN, (11) -N (R2) 2, (12) -C (O) OR2, (13) -OR2, (14) - (CH2) n-heterocyclyl C5-10, (15) - (CH2) C6-10 n-aryl, and (16) - (CH2) C5-10 n-heteroaryl, wherein said heterocyclyl, aryl, and heteroaryl are each optionally substituted with 1 to 3 groups of (a) halogen, (b) hydroxyl , (c) C1-6 alkyl, (d) -CN; (e) - (CH2) nCF3, or (f) -C6-10 aryl; R2 is selected from the group consisting of (1) hydrogen, (2) hydroxyl, (3) C1-6 alkyl, which is unsubstituted or substituted by one or more halogens, (4) - (CH2) CF3, (5 ) - (CH2) nF, (6) -C3-10 cycloalkyl, (7) -C6-10 aryl, (8) -C5-10 heteroaryl, and (9) -C5-10 heterocyclyl, wherein said cycloalkyl, aryl , heterocyclyl or heteroaryl are each optionally substituted with 1 to 3 groups of Ra and n is independently 0 to 4 or a pharmaceutically acceptable salt thereof. |