A survey of reported synthesis of methaqualone and some positional and structural isomers.

Methaqualone (2-methyl-3-o-tolyl-4(3H)-quinazolinone) is the illicit synthetic drug of choice amongst South African drug users. Historically police and forensic investigation has proven that all methaqualone seized by the South African Police Service originates from illicit manufacturing sites both inside, and outside South Africa's borders. From a drug enforcement, and forensic point of view it is, thus, of utmost importance that the various synthetic routes available to the illicit "chemist" are fully documented and understood. This is a prerequisite for effective illicit laboratory investigation, as well as chemical and precursor monitoring. This paper gives a brief introduction to the current status with regard to methaqualone use and production in South Africa, as well as an extensive review of the synthesis of methaqualone and selected isomers reported since 1946. A table summarizing synthetic routes reported in 32 reference sources is provided.