11C-labeled benzyl-lactam compounds and their use as imaging agents

A compound of formula I:

• or a pharmaceutically acceptable salt thereof,
• wherein
• X is CH or N;
• Y is —C(OR1)(R2)2 or —N(R3)2;
• R1 is H or C1-C6 alkyl;
• each R2 is independently C1-C6 alkyl, or both R2 groups are taken together form —(CH2)n—, where n is an integer ranging from 2 to 7;
• each R3 is independently C1-C6 alkyl, or both R3 groups are taken together to form —(CH2)2—O—(CH2)2—, —(CH2)2—(NR4)—(CH2)2— or —(CH2)m—, where m is an integer ranging from 2 to 7;
• R4 is H or CH3;
• and
• * is a chiral carbon atom, wherein the carbon is a racemate, an (R)-enantiomer, an (S) -enantiomer, or a mixture thereof.