Patent ID: 8895744

Claim:
A compound of formula (I): wherein when R1 is nil or when R1 is attached in the 2 position of the α-carboline ring, R1 is selected from the group consisting of: when R1 is attached in the 3 position of the α-carboline ring, R1 is selected from the group consisting of: when R1 is attached in the 4 position of the α-carboline ring, R1 is selected from the group consisting of: wherein R2 is selected from the group consisting of: wherein R3 is selected from the group consisting of hydrogen, methyl, ethoxymethyl, tert-butyloxycarbonyl and benzenesulfonyl; wherein a dashed line across a bond indicates the point of attachment of the group to the α-carboline ring, or a stereoisomer, enantiomer, diastereoisomer or a pharmaceutically acceptable salt thereof.