Methaqualone
Methaqualone is a synthetic quinazolinone derivative with the chemical formula C₁₆H₁₄N₂O, functioning as a sedative-hypnotic agent that potentiates GABA_A receptors to depress central nervous system activity, producing effects akin to barbiturates.[1] Originally synthesized in 1951 by Indian researchers exploring antimalarial compounds, its sedative properties were identified in the 1950s, leading to medical patents and introduction as a prescription drug for short-term treatment of insomnia and anxiety by the early 1960s.[1][2] Marketed under brand names including Quaalude in the United States, Mandrax in South Africa and Europe, and Sopor elsewhere, methaqualone initially gained approval for its rapid onset of hypnosis and muscle relaxation without the hangover associated with earlier sedatives, peaking in prescription volume during the 1970s.[1] However, its euphoric, disinhibiting effects at recreational doses—often combined with alcohol or other depressants—fueled widespread abuse, contributing to dependency, tolerance buildup, and acute risks such as respiratory depression, convulsions, and fatal overdoses estimated at 8-20 grams orally.[1][3] By the late 1970s, escalating reports of addiction and illicit diversion prompted regulatory scrutiny; in the U.S., it was rescheduled from II to I under the Controlled Substances Act in 1984, classifying it as having no accepted medical use and high abuse liability, resulting in manufacturer withdrawal and a manufacturing ban.[1] Despite global prohibitions, clandestine production persists in regions like South Africa, where Mandrax remains a prevalent street drug often smoked with cannabis, underscoring methaqualone's enduring challenges in enforcement and public health.[2]Chemistry and Pharmacology
Chemical Properties and Synthesis
Methaqualone, chemically known as 2-methyl-3-(2-methylphenyl)-3,4-dihydroquinazolin-4-one, possesses the molecular formula C_{16}H_{14}N_{2}O and a molar mass of 250.30 g/mol.[1] It belongs to the quinazolinone class of heterocyclic compounds.[1] The compound was first synthesized in 1951 by Indian chemists Indra Kishore Kacker and Syed Husain Zaheer as part of research into potential therapeutic agents.[4] In its pure form, methaqualone free base manifests as white crystals with little to no odor and a bitter taste.[1] The melting point of the free base ranges from 113 °C to 116 °C, while the hydrochloride salt melts at 255–265 °C.[5] Methaqualone exhibits low solubility in water but dissolves readily in organic solvents, including 1 part in 12 parts ethanol, 1 part in 1 part chloroform, and 1 part in 50 parts ether.[1][5]| Property | Free Base Value | Hydrochloride Salt Value |
|---|---|---|
| Appearance | White crystals | Crystals |
| Melting Point (°C) | 113–116 | 255–265 |
| Solubility in Water | Practically insoluble | Low |