[(9S)-8-(5-Chloropyridin-2-yl)-7-oxo-2,5,8-triazabicyclo[4.3.0]nona-1,3,5-trien-9-yl]4-methylpiperazine-1-carboxylate; Lunesta; (S)-Zopiclone

Eszopiclone is the active stereoizomer of Zopiclone and belongs to the class of drug known as cyclopyrrones. It is a nonbenzodiazepine hypnotic agent used as a treatment for insomnia.