Positive allosteric modulator selective for mGlu2 receptors. Potentiates glutamate-stimulated [35S]GTPγS binding (EC50 values are 1.7 and > 10 μM for mGlu2 and mGlu3 receptors respectively). Devoid of any activity at mGlu5 and mGlu7 receptors. Promotes cognitive flexibility in a rat model.