1H-Pyrrolo[2,1-c][1,2,4]benzothiadiazine, 2,3,3a,4-tetrahydro-, 5,5-dioxide, (3aR)- is a low activity isomer of S 18986. S 18986 is a AMPA receptor positive modulator with EC2 (Concentration that doubles the intensity of the AMPA-induced current) of 35 μM.