BigPatents India

An improved process for Zopiclone comprises three steps: one pot synthesis of 6-(5-chloropyrid-2-yl)-5,7-dioxo-5, 6-dihydropyrrolo [3,4-b]pyrazine (IV) from pyrazine-2, 3-dicarboxylic acid (II) and 2-amino-5-chloropyridine (III) without using any hazardous solvent or reagent; selective reduction of the 6-(5-chloropyrid-2yl)-5,7-dioxo-5, 6-dihydropyrrolo [3,4-b]pyrazine (IV) with sodium borohydride in biphasic system to obtain 6-(5-chloropyrid-2-yl)-5-hydroxy-7-oxo-5,6-dihydropyrrolo-[3,4-b]pyrazine (V) and further converted compound (V) to Zopiclone (I). Drawing: NIL Total Pages: 24 Fig. Nil