Carbromal is a hypnotic/sedative originally synthesized in 1909 by Bayer and subsequently marketed as Adalin.[1][2] The drug was later sold by Parke-Davis in combination with pentobarbital, under the name Carbrital.[3]
Synthesis
Diethylmalonic acid [510-20-3] (1) is decarboxylated to 2-ethylvaleric acid [20225-24-5] (2). The Hell-Volhard-Zelinsky reaction converts this to 2-Bromo-2-Ethylbutyryl Bromide [26074-53-3] (3). Reaction with urea with affords carbromal (4).
^ abDE 22571, "Verfahren dur Darstellung von Bromodiäthylacetylharnstoff [Method for the preparation of bromodiethylacetylurea]", published 1910-09-17, assigned to Friedrich Bayer & Co.