Barbiturate

Barbiturates are a chemical class of organic compounds built on a barbituric acid core, a six-membered ring containing two nitrogen atoms and three carbonyl groups, formed by combining urea with a malonic acid unit. Individual members carry two substituents on the central carbon of that ring, typically alkyl, aryl, or allyl groups, which distinguish the compounds. Barbiturates act as positive modulators at the GABA-A receptor, producing sedative, hypnotic and anticonvulsant effects with a narrow margin of safety. The thiobarbiturates are a close variant in which one ring oxygen is replaced by a sulfur atom.