Enantioselective synthesis of a pyrrolo-benzothiadiazine derivative S 18986, a new AMPA receptor positive modulator

Enantioselective reduction of pyrrolo-benzothiadiazine 6 using various chiral reducing agents has been studied and led to efficient synthesis of 8 (S 18986) which was established to be of (S) configuration by single crystal X-ray diffraction analysis. S 18986 is a potent and selective AMPA positive modulator which displays total stereoselectivity, the (R) enantiomer being completely inactive.