<unk>  is a methyl homolog of the mammalian neurotransmitter phenethylamine with the chemical formula . The carbon atom adjacent to the primary amine is a stereogenic center, and<unk>  is composed of a racemic 1:1 mixture of two enantiomers. This racemic mixture can be separated into its optical isomers: levoamphetamine and dextroamphetamine. At room temperature, the pure free base of<unk>  is a mobile, colorless, and volatile liquid with a characteristically strong amine odor, and acrid, burning taste. Frequently prepared solid salts of<unk>  include<unk>  adipate, aspartate, hydrochloride, phosphate, saccharate, sulfate, and tannate. Dextroamphetamine sulfate is the most common enantiopure salt.<unk>  is also the parent compound of its own structural class, which includes a number of psychoactive derivatives. In organic chemistry,<unk>  is an excellent chiral ligand for the stereoselective synthesis of . Substituted derivatives The substituted derivatives of<unk> , or "substituted<unk> s", are a broad range of chemicals that contain<unk>  as a "backbone"; specifically, this chemical class includes derivative compounds that are formed by replacing one or more hydrogen atoms in the<unk>  core structure with substituents. The class includes<unk>  itself, stimulants like methamphetamine, serotonergic empathogens like MDMA, and decongestants like ephedrine, among other subgroups. Synthesis Since the first preparation was reported in 1887, numerous synthetic routes to<unk>  have been developed. The most common route of both legal and illicit<unk>  synthesis employs a non-metal reduction known as the Leuckart reaction (method 1). In the first step, a reaction between phenylacetone and formamide, either using additional formic acid or formamide itself as a reducing agent, yields . This intermediate is then hydrolyzed using hydrochloric acid, and subsequently basified, extracted with organic solvent, concentrated, and distilled to yield the free base. The free base is then dissolved in an organic solvent, sulfuric acid added, and<unk>  precipitates out as the sulfate salt. A number of chiral resolutions have been developed to separate the two enantiomers of<unk> . For example, racemic<unk>  can be treated with to form a diastereoisomeric salt which is fractionally crystallized to yield dextroamphetamine. Chiral resolution remains the most economical method for obtaining optically pure<unk>  on a large scale. In addition, several enantioselective syntheses of<unk>  have been developed. In one example, optically pure is condensed with phenylacetone to yield a chiral Schiff base. In the key step, this intermediate is reduced by catalytic hydrogenation with a transfer of chirality to the carbon atom alpha to the amino group. Cleavage of the benzylic amine bond by hydrogenation yields optically pure dextroamphetamine. A large number of alternative synthetic routes to<unk>  have been developed based on classic organic reactions. One example is the Friedel–Crafts alkylation of benzene by allyl chloride to yield beta chloropropylbenzene which is then reacted with ammonia to produce racemic<unk>  (method 2). Another example employs the Ritter reaction (method 3). In this route, allylbenzene is reacted acetonitrile in sulfuric acid to yield an organosulfate which in turn is treated with sodium hydroxide to give<unk>  via an acetamide intermediate. A third route starts with which through a double alkylation with methyl iodide followed by benzyl chloride can be converted into acid. This synthetic intermediate can be transformed into<unk>  using either a Hofmann or Curtius rearrangement (method 4). A significant number of<unk>  syntheses feature a reduction of a nitro, imine, oxime, or other nitrogen-containing functional groups. In one such example, a Knoevenagel condensation of benzaldehyde with nitroethane yields . The double bond and nitro group of this intermediate is reduced using either catalytic hydrogenation or by treatment with lithium aluminium hydride (method 5). Another method is the reaction of phenylacetone with ammonia, producing an imine intermediate that is reduced to the primary amine using hydrogen over a palladium catalyst or lithium aluminum hydride (method 6).<unk>  synthetic routes Detection in body fluids<unk>  is frequently measured in urine or blood as part of a drug test for sports, employment, poisoning diagnostics, and forensics. Techniques such as immunoassay, which is the most common form of<unk>  test, may cross-react with a number of sympathomimetic drugs. Chromatographic methods specific for<unk>  are employed to prevent false positive results. Chiral separation techniques may be employed to help distinguish the source of the drug, whether prescription<unk> , prescription<unk>  prodrugs, (e.g., selegiline), over-the-counter drug products that contain levomethamphetamine, or illicitly obtained substituted<unk> s. Several prescription drugs produce<unk>  as a metabolite, including benzphetamine, clobenzorex, famprofazone, fenproporex, lisdexamfetamine, mesocarb, methamphetamine, prenylamine, and selegiline, among others. These compounds may produce positive results for<unk>  on drug tests.<unk>  is generally only detectable by a standard drug test for approximately 24 hours, although a high dose may be detectable for days. For the assays, a study noted that an enzyme multiplied immunoassay technique (EMIT) assay for<unk>  and methamphetamine may produce more false positives than liquid chromatography–tandem mass spectrometry. Gas chromatography–mass spectrometry (GC–MS) of<unk>  and methamphetamine with the derivatizing agent chloride allows for the detection of methamphetamine in urine. GC–MS of<unk>  and methamphetamine with the chiral derivatizing agent Mosher's acid chloride allows for the detection of both dextroamphetamine and dextromethamphetamine in urine. Hence, the latter method may be used on samples that test positive using other methods to help distinguish between the various sources of the drug.
Amphetamine
Benzphetamine
Methamphetamine
Benzocaine
Nicotine
3,4-Methylenedioxyamphetamine
Heroin
Cannabis 