A CAS Registry Number, also referred to as CASRN or CAS Number, is a unique numerical identifier assigned by the Chemical Abstracts Service (CAS) to every chemical substance described in the open scientific literature (currently including all substances described from 1957 through the present, plus some substances from the early or mid 1900s), including organic and inorganic compounds, minerals, isotopes, alloys and nonstructurable materials (UVCBs, substances of unknown or variable composition, complex reaction products, or biological origin).
The registry maintained by CAS is an authoritative collection of disclosed chemical substance information. It currently identifies more than 144 million unique organic and inorganic substances and 67 million protein and DNA sequences, plus additional information about each substance. It is updated with around 15,000 additional new substances daily.
Historically, chemicals have been identified by a wide variety of synonyms. Frequently these are arcane and constructed according to regional naming conventions relating to chemical formulae, structures or origins. Well-known chemicals may additionally be known via multiple generic, historical, commercial, and/or (black)-market names.
CAS Registry Numbers (CASRN) are simple and regular, convenient for database searches. They offer a reliable, common and international link to every specific substance across the various nomenclatures and disciplines used by branches of science, industry, and regulatory bodies. Almost all molecule databases today allow searching by CAS Registry Number.
On the other hand, CASRNs are not related to chemistry, are proprietary and unrelated to any previous systems, and do not readily form phonetic analogs or synonyms.
A CAS Registry Number has no inherent meaning but is assigned in sequential, increasing order when the substance is identified by CAS scientists for inclusion in the CAS REGISTRY database.
A CASRN is separated by hyphens into three parts, the first consisting from two up to seven digits, the second consisting of two digits, and the third consisting of a single digit serving as a check digit. This current format gives CAS a maximum capacity of 1,000,000,000 unique identifiers.
The check digit is found by taking the last digit times 1, the preceding digit times 2, the preceding digit times 3 etc., adding all these up and computing the sum modulo 10. For example, the CAS number of water is 7732-18-5: the checksum 5 is calculated as (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) = 105; 105 mod 10 = 5.
To find the CAS number of a compound given its name, formula or structure, the following free resources can be used:
(–)-18-Methylaminocoronaridine (18-MAC) is a second generation synthetic derivative of ibogaine developed by the research team led by the pharmacologist Stanley D. Glick from the Albany Medical College and the chemist Martin E. Kuehne from the University of Vermont. In animal studies it has shown around twice the efficacy of the related compound 18-methoxycoronaridine (18-MC) at reducing self-administration of morphine when administered in an equivalent dose, although it is less effective than 18-MC at reducing methamphetamine administration. Similarly to 18-MC itself, 18-MAC acts primarily as a selective α3β4 nicotinic acetylcholine antagonist, and is even more selective than 18-MC with very little activity as an NMDA antagonist and only slight affinity for the delta opioid receptor.2,3,4,5-Tetramethoxyamphetamine
Tetramethoxyamphetamine, or 2,3,4,5-tetramethoxyamphetamine, is a lesser-known psychedelic drug and a substituted amphetamine. Tetramethoxyamphetamine was first synthesized by Alexander Shulgin. In his book PiHKAL (Phenethylamines i Have Known And Loved), the minimum dosage is listed as 50 mg, and the duration unknown. Tetramethoxyamphetamine produces a threshold, mydriasis, and a headache. Very little data exists about its pharmacological properties, metabolism, and toxicity.2-Methyl-3-phenylpiperidine
2-Methyl-3-phenylpiperidine is a psychostimulant.4-Caffeoyl-1,5-quinide
4-Caffeoyl-1,5-quinide (4-caffeoylquinic-1,5-lactone or 4-CQL) is found in roasted coffee beans. It is formed by lactonization of 4-O-caffeoylquinic acid during the roasting process.
It is reported to possess opioid antagonist properties in mice.D-161
D-161 is a chemical known in research circles as a triple reuptake inhibitor. Although this compound has lent support to the inclusion of dopamine in the monoamine hypothesis of depression, D-161 has not been tested in clinical trials.Dihydrochandonium
Dihydrochandonium is an aminosteroid non-depolarizing neuromuscular blocking agent.Eugenodilol
Eugenodilol is a beta blocker derived from eugenol.F-2 (drug)
F-2, or 6-(2-aminopropyl)-5-methoxy-2-methyl-2,3-dihydrobenzofuran, is a lesser-known psychedelic drug. F-2 was first synthesized by Alexander Shulgin. In his book PiHKAL (Phenethylamines i Have Known And Loved), the minimum dosage is listed as 15 mg, and the duration unknown. F-2 produces few to no effects at this dose, and it is unknown what (if any) effects it would produce if a higher dose were to be tried. Very little data exists about the pharmacological properties, metabolism, and toxicity of F-2.Flusoxolol
Flusoxolol is a selective beta 1-adrenoblocker.GBR-13119
GBR-13119 is a psychostimulant and dopamine re-uptake inhibitor.Hydroxytertatolol
Hydroxytertatolol is a beta blocker. It is a derivative of tertatolol.Leptacline
Leptacline (INN) (developmental code name SD 210-32) is a drug described as a respiratory stimulant that was never marketed. It has a similar chemical structure to various piperidine and piperazine psychostimulants.Metazosin
Metazosin is an antihypertensive alpha-adrenergic antagonist.Phendioxan
Phendioxan is an alpha 1-adrenoreceptor antagonist.Piperacetazine
Piperacetazine (Quide) is an antipsychotic prodrug, most notably used for schizophrenia.Procinolol
Procinolol is a beta adrenergic receptor antagonist.RB-3007
RB-3007 is an orally active analogue of RB-101. It acts as an enkephalinase inhibitor, which is used in scientific research.Ritipenem
Ritipenem is a penem class antimicrobial agent. Ritipenem is manufactured by Tanabe Seiyaku in the ritipenem acoxil prodrug form, which can be taken orally . It is not FDA approved in the United States as of 2008.Tetrahydropapaveroline
Tetrahydropapaveroline (norlaudanosoline) is a benzyltetrahydroisoquinoline alkaloid.It can be formed in trace amounts in the brain by a condensation reaction of dopamine and dopaldehyde (a metabolite of dopamine).It inhibits dopamine uptake within the cerebral cortex.