 | |
| Names | |
|---|---|
| Preferred IUPAC name Acridine[3] | |
| Other names | |
| Identifiers | |
| |
3D model (JSmol) | |
| 120200 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.005.429 |
| EC Number |
|
| 143403 | |
| RTECS number |
|
| UNII | |
| UN number | 2713 |
| |
| |
| Properties | |
| C13H9N | |
| Molar mass | 179.222 g·mol−1 |
| Appearance | White powder |
| Odor | Irritating |
| Density | 1.005 g/cm3 (20 °C)[1] |
| Melting point | 106–110 °C (223–230 °F; 379–383 K) atstandard pressure[1] |
| Boiling point | 344.86 °C (652.75 °F; 618.01 K) atstandard pressure[1] |
| 46.5 mg/L[1] | |
| Solubility | Soluble inCCl4,alcohols,(C2H5)2O,C6H6[1] |
| logP | 3.4[1] |
| Vapor pressure | 0.34 kPa (150 °C) 2.39 kPa (200 °C) 11.13 kPa (250 °C)[4] |
| Acidity (pKa) | 5.58 (20 °C)[1] |
| UV-vis (λmax) | 392 nm[5] |
| −123.3×10−6 cm3/mol | |
| Thermochemistry | |
| 205.07 J/mol·K[4] | |
Std molar entropy(S⦵298) | 208.03 J/mol·K[4] |
Std enthalpy of formation(ΔfH⦵298) | 179.4 kJ/mol[1] |
Std enthalpy of combustion(ΔcH⦵298) | 6581.3 kJ/mol[4] |
| Hazards | |
| GHS labelling: | |
 [5] | |
| Danger | |
| H302,H312,H315,H319,H332,H335[5] | |
| P261,P264,P270,P271,P280,P301+P312,P302+P352,P304+P312,P304+P340,P305+P351+P338,P312,P321,P322,P330,P332+P313,P337+P313,P362,P363,P403+P233,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 500 mg/kg (mice, oral)[2] |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 0.2 mg/m3 (benzene-soluble fraction)[6] |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Acridine is anorganic compound and anitrogen heterocycle with the formula C13H9N. Acridines are substituted derivatives of the parent ring. It is a planar molecule that is structurally related toanthracene with one of the central CH groups replaced by nitrogen. Like the related moleculespyridine andquinoline, acridine is mildly basic. It is an almost colorless solid, which crystallizes in needles. There are few commercial applications of acridines; at one time acridine dyes were popular, but they are now relegated to niche applications, such as withacridine orange. The name is a reference to the acrid odour and acrid skin-irritating effect of the compound.
Carl Gräbe andHeinrich Caro first isolated acridine in 1870 fromcoal tar.[7] Acridine is separated from coal tar by extracting with dilutesulfuric acid. Addition ofpotassium dichromate to this solutionprecipitates acridine bichromate. The bichromate isdecomposed usingammonia.
Acridine and its derivatives can be prepared by many synthetic processes. In theBernthsen acridine synthesis,diphenylamine is condensed withcarboxylic acids in the presence ofzinc chloride. Whenformic acid is the carboxylic acid, the reaction yields the parent acridine. With the higherlarger carboxylic acids, the derivatives substituted at themeso carbon atom are generated.
Other older methods for theorganic synthesis of acridines include condensing diphenylamine withchloroform in the presence ofaluminium chloride, by passing the vapours of orthoaminodiphenylmethane over heatedlitharge, by heatingsalicylaldehyde withaniline andzinc chloride or by distillingacridone (9-position acarbonyl group) overzinc dust.[8] Another classic method for the synthesis of acridones is theLehmstedt-Tanasescu reaction.
Inenzymology, anacridone synthase (EC2.3.1.159) is anenzyme thatcatalyzes thechemical reaction
Thus, the twosubstrates of this enzyme aremalonyl-CoA andN-methylanthraniloyl-CoA, whereas its threeproducts areCoA,1,3-dihydroxy-N-methylacridone, andCO2.[9]
Acridine displays the reactions expected of an unsaturatedN-heterocycle. It undergoesN-alkylation withalkyl iodides to form alkyl acridinium iodides, which are readily transformed by the action of alkalinepotassium ferricyanide toN-alkylacridones.
Acridine and its homologues are weakly basic. Acridine is a photobase which has a ground statepKa of 5.1, similar to that ofpyridine, and an excited state pKa of 10.6.[10] It also shares properties withquinoline.
Acridines can be reduced to the 9,10-dihydroacridines, sometimes called leucoacridines. Reaction withpotassium cyanide gives the 9-cyano-9,10-dehydro derivative. On oxidation withpotassium permanganate, it yields acridinic acid (C9H5N(CO2H)2) otherwise known asquinoline-1,2-dicarboxylic acid.[8] Acridine is easilyoxidized byperoxymonosulfuric acid to the acridineamine oxide. The carbon 9-position of acridine is activated foraddition reactions.[11]
Severaldyes and drugs feature the acridine skeleton.[12] Many acridines, such asproflavine, also haveantiseptic properties. Acridine and related derivatives (such asamsacrine) bind toDNA andRNA due to their abilities tointercalate.Acridine orange (3,6-dimethylaminoacridine) is anucleic acid-selective metachromaticstain useful for cell cycle determination.
At one time acridine dyes were commercially significant, but they are now uncommon because they are notlightfast. Acridine dyes are prepared by condensation of1,3-diaminobenzene derivatives. Illustrative is the reaction of2,4-diaminotoluene with acetaldehyde:[13]
9-Phenylacridine is the parent base ofchrysaniline or 3,6-diamino-9-phenylacridine, which is the chief constituent of the dyestuff phosphine (not to be confused withphosphine gas), a byproduct in the manufacture ofrosaniline. Chrysaniline forms red-coloured salts, which dyesilk andwool in a fine yellow; and the solutions of the salts are characterized by their fine yellowish-green fluorescence. Chrysaniline was synthesized by O. Fischer and G. Koerner by condensingo-nitrobenzaldehyde with aniline, the resultingo-nitro-p-diaminotriphenylmethane being reduced to the correspondingo-amino compound, which on oxidation yields chrysaniline.
Benzoflavin, an isomer of chrysaniline, is also a dyestuff, and has been prepared by K. Oehler fromm-phenylenediamine andbenzaldehyde. These substances condense to form tetraaminotriphenylmethane, which, on heating with acids, loses ammonia and yields 3,6-diamino-9,10-dihydrophenylacridine, from which benzoflavin is obtained by oxidation. It is a yellow powder, soluble in hot water.[8]
Acridine is known to induce small insertions or deletions in nucleotide sequences, resulting inframeshift mutations.[14] This compound was useful to identify the triplet nature of thegenetic codes.[14]
As established byX-ray crystallography, acridine has been obtained in eightpolymorphs. All feature very similar planar molecules with nearly identical bond lengths and bond distances.[15][16]
Acridine is a skin irritant. ItsLD50 (rats, oral) is 2,000 mg/kg and 500 mg/kg (mice, oral).[2]
One or more of the preceding sentences incorporates text from a publication now in thepublic domain: Chisholm H, ed. (1911). "Acridine".Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. p. 155.
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