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.

Synthesis and anticonvulsant activity of some new 2-substituted 3-aryl-4(3H)-quinazolinones.

A series of 4(3H)-quinazolinones structurally related to 2-methyl-3-o-tolyl-4(3H)-quinazolinone (methaqualone, 3) were synthesized and evaluated for anticonvulsant activity. Preliminary screening of these compounds revealed that 2-[2-oxo-2-(4-pyridyl)ethyl]-3-aryl-4(3H)-quinazolinones 6l and 8i, 8k, and 8p-r having a single ortho substituent on the 3-aryl group had the most promising anticonvulsant activity. Compounds 6l and 8i possessing 3-o-tolyl and 3-o-chlorophenyl groups, respectively, showed good protection against MES- and scMet-induced seizures, combined with relatively low neurotoxicity after intraperitoneal administration in mice. They also exhibited low toxicity in tests for determining the mean hypnotic dose (HD50) and the median lethal dose (LD50). Although these compounds were markedly more potent as anticonvulsants when administered orally in mice and rats, they were also more neurotoxic. This neurotoxicity was particularly acute in oral tests with rats, which resulted in marginal protective indices. In drug differentiation tests, compound 6l was ineffective against seizures induced by bicuculline, picrotoxin, and strychnine, while 8i showed some protection against picrotoxin-induced seizures.

The isolation and identification of precursors and reaction products in the clandestine manufacture of methaqualone and mecloqualone.

Abuse of the hypnotic quinazolinone is well recognized and increasing. Clandestine laboratories producing methaqualone (2-methyl-3-ortho-tolyl-4(3H) quinazolinone) and mecloqualone (2-methyl-3-ortho-chlorophenyl-4(3H) quinazolinone) have been discovered throughout the United States. These laboratories utilize one of many synthesis routes to produce the illicit quinazolinone. Frequently, the clandestine chemist has little, if any, formal education in chemistry; does not keep notes; and does not label flasks and beakers containing solutions. The forensic chemist may be asked to analyze unmarked reaction mixtures that were seized in a clandestine laboratory raid. As a result, a rapid method of isolation and identification of the precursors and products of such a mixture is presented.

The clandestine drug laboratory situation in the United States.

Clandestine, or illegal, laboratories are operated by the criminal element to circumvent legal requirements with the goal of supplying drugs of abuse to the illicit market. Investigation of clandestine drug manufacturing laboratories is a high priority of the U.S. Drug Enforcement Administration (DEA) because elimination of these laboratories will prevent drugs of abuse from reaching the illicit drug traffic. One of the important responsibilities of forensic chemists assisting in investigations of clandestine drug laboratories is to be familiar with the methods of synthesis being used by clandestine laboratory operators. A review of clandestine laboratory seizures during the period of 1978 through 1981 will be provided to familiarize forensic chemists with current information on the types of laboratories being seized in the United States and the methods of synthesis being used.

[On derivatives of 4-oxo-3,4-dihydropyrido[2,3-d]pyrimidine (author's transl)]. / Uber Derivate des 4-Oxo-3,4-dihydro-pyrido[2,3-d]pyrimidin.

A typical representative of the hypnotic and anticonvulsive 4-quinazoline group is methaqualone (1). A number of new derivatives of 4-oxo-3,4-dihydropyrido[2,3-d]pyrimidine (10) were synthetized by substituting the benzene ring in the quinazolone molecule by the pyridine ring. The synthesis was achieved by the condensation of 2-acetaminonicotinic acid (9) and a primary amine or by the reaction of 2-aminonicotinic acid (8) with acetic acid and a primary amine. These new compounds were tested on animals for antiphlogistic, analgetic and antipyretic activities and for effects on the central nervous system as well. It was tried to establish, on the basis of the results obtained, relations between the chemical constitution and the pharmacological efficacy. It was found that, depending on the nature of the substituents in the position 3; either the antiphlogistic, analgetic and antipyretic effects or the anticonvulsive action will prevail.

Synthesis of methaqualone and its diphasic titration in pure and tablet forms.

A one-step synthesis of methaqualone from N-acetylanthranilic acid and o-toluidine in the absence of a catalyst is described. A rapid diphasic titration procedure for its microestimation in pure and tablet forms, using dioctyl sodium sulfosuccinate and dimethyl yellow screened with oracet blue B, is proposed. The data were compared with those obtained from nonaqueous titration methods.

Synthesis and central nervous system activity of quinazolones related to 2-methyl-3-(o-tolyl)-4(3H)-quinazolone (methaqualone).

A number of derivatives of 2-methyl-3-(o-tolyl)-4(3H)-quinazolone bearing new substituents on the 2-methyl group have been synthesized. It was established that most substitutions at this position reduce or remove the CNS depressant activity of methaqualone. From the series prepared only the 2-fluoromethyl derivative or certain isothiouronium salts, which could be hydrolyzed in vivo to the 2-mercaptomethyl derivative, showed activity of the same magnitude as methaqualone.