Anthranilic acid Methaqualone

The illicit manufacture of methaqualone still persists in South Africa. Authorities in that country seized 7,200 litres of acetic anhydride and 450 kg of anthranilic acid during 2003. A further 550 kg of anthranilic acid were seized in 2004. The uncovered laboratories appear to have been operating on a smaller scale than those previously encountered. In fact, from the information available to the Board, it now appears that large-scale manufacture of methaqualone is taking place mainly in China. 

The key precursors, or ingredients, in the manufacture of methaqualone are the chemicals N-acetylanthran-lic acid and anthranilic acid. Because methaqualone is produced illegally, the drug is frequently cut, or adulterated, with other substances called fillers, ranging from talcum powder to heroin. 

Anthranilic acid (151) and o-toluidine are the intermediates used to make Methaqualone (152), an important hypnotic (Scheme 32)83. It was introduced as a daytime sedative and... 

During 2004, the detection of methaqualone laboratories declined in South Africa in terms of both the number of illicit laboratories dismantled and the capacity of those laboratories. During that period, seven such laboratories were dismantled and 20 kg of anthranilic acid were seized. At the same time, detections of methamphetamine/methcathinone laboratories increased in the country. The Board is therefore attempting to determine whether the methaqualone laboratories have relocated outside the country or whether amphetamine-type stimulants have now replaced methaqualone as the drug of choice in the country. 

Some new facile syntheses for 2-methyl-3-(o-tolyl)quinazolin-4-one (methaqualone) " and 3-aryl-2-mercapto-quinazolin-4-ones have been announced. The former synthesis can be carried out in high yield in one pot by allowing isatoic anhydride to react sequentially with aniline in toluene and pentane-2,5-dione in ethanolic hydrogen chloride. The latter preparation consists of condensing aryl isothiocyanates with anthranilic acid in hot acetic acid-sodium acetate mixture. 

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