Wiktionary
quinazolinone
n. (context organic compound English) A heterocyclic chemical compound with two isomers, used as a sedative.
Wikipedia
Quinazolinone
Quinazolinone is a heterocyclic chemical compound. There are two structural isomers, 2-quinazolinone and 4-quinazolinone, with the 4-isomer being the more common.