ZALEPLON

                    3-amino-1h-pyrazole-4-carbonitrile

ZOLPIDEM

                    2-(4-methylphenyl)-6-methylimidazole pyridine

                    2-(4-methylphenyl)-6-methylimidazole pyridine-3-acetonitrile

ZOPICLONE

                    2,3-pyrazine dicarboxylic anhydride

                    2-amino-5-chloropyridine

                    6-(5-chloro-2-piperidinyl)-6,7-dihydro-7-hydroxy-5h-pyrrolo[3,4-b]pyrazine-5-one