Isoquinoline
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Names | |||
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Preferred IUPAC name
Isoquinoline[1] | |||
Other names
Benzo[c]pyridine
2-benzazine | |||
Identifiers | |||
3D model (
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ChEBI | |||
ChEMBL | |||
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DrugBank | |||
ECHA InfoCard
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100.003.947 | ||
EC Number |
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PubChem CID
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UNII | |||
CompTox Dashboard (EPA)
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Properties | |||
C9H7N | |||
Molar mass | 129.162 g·mol−1 | ||
Appearance | Colorless oily liquid; hygroscopic platelets when solid | ||
Density | 1.099 g/cm3 | ||
Melting point | 26–28 °C (79–82 °F; 299–301 K) | ||
Boiling point | 242 °C (468 °F; 515 K) | ||
Acidity (pKa) | pKBH+ = 5.14[2] | ||
−83.9·10−6 cm3/mol | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Isoquinoline is an individual chemical specimen - a
Properties
Isoquinoline is a colorless
Being an
Production
Isoquinoline was first isolated from coal tar in 1885 by Hoogewerf and van Dorp.[9] They isolated it by fractional crystallization of the acid sulfate. Weissgerber developed a more rapid route in 1914 by selective extraction of coal tar, exploiting the fact that isoquinoline is more basic than quinoline. Isoquinoline can then be isolated from the mixture by fractional crystallization of the acid sulfate.
Although isoquinoline derivatives can be synthesized by several methods, relatively few direct methods deliver the unsubstituted isoquinoline. The Pomeranz–Fritsch reaction provides an efficient method for the preparation of isoquinoline. This reaction uses a benzaldehyde and aminoacetoaldehyde diethyl acetal, which in an acid medium react to form isoquinoline.[10] Alternatively, benzylamine and a glyoxal acetal can be used, to produce the same result using the Schlittler-Müller modification.[11]
Several other methods are useful for the preparation of various isoquinoline derivatives.
In the Bischler–Napieralski reaction an β-phenylethylamine is acylated and cyclodehydrated by a Lewis acid, such as phosphoryl chloride or phosphorus pentoxide. The resulting 1-substituted 3,4-dihydroisoquinoline can then be dehydrogenated using palladium. The following Bischler–Napieralski reaction produces papaverine.
The
In a Pictet–Spengler reaction, a condensation of a β-
a biological Pictect-Spengler synthesis:Intramolecular aza Wittig reactions also afford isoquinolines.
Applications of derivatives
Isoquinolines find many applications, including:
- anesthetics; dimethisoquinis one example (shown below).
- antihypertension agents, such as quinapril and debrisoquine (all derived from 1,2,3,4-tetrahydroisoquinoline).
- antiretroviral agents, such as saquinavir with an isoquinolyl functional group, (shown below).
- vasodilators, a well-known example, papaverine, shown below.
Bisbenzylisoquinolinium compounds are compounds similar in structure to
In the human body
Other uses
Isoquinolines are used in the manufacture of
See also
- Eletefine (1998), an isoquinoline alkaloid
- Naphthalene, an analog without the nitrogen atom
References
- ISBN 978-0-85404-182-4.
- ^ a b Brown, H.C., et al., in Baude, E.A. and Nachod, F.C., Determination of Organic Structures by Physical Methods, Academic Press, New York, 1955.
- ^ Gilchrist, T.L. (1997). Heterocyclic Chemistry (3rd ed.). Essex, UK: Addison Wesley Longman.
- ^ Harris, J.; Pope, W.J. "isoQuinoline and the isoQuinoline-Reds" Journal of the Chemical Society (1922) volume 121, pp. 1029–1033.
- ^ Katritsky, A.R.; Pozharskii, A.F. (2000). Handbook of Heterocyclic Chemistry (2nd ed.). Oxford, UK: Elsevier.
- ^ Katritsky, A.R.; Rees, C.W.; Scriven, E.F. (Eds.). (1996). Comprehensive Heterocyclic Chemistry II: A Review of the Literature 1982–1995 (Vol. 5). Tarrytown, NY: Elsevier.
- ^ Nagatsu, T. "Isoquinoline neurotoxins in the brain and Parkinson's disease" Neuroscience Research (1997) volume 29, pp. 99–111.
- ^ O'Neil, Maryadele J. (Ed.). (2001). The Merck Index (13th ed.). Whitehouse Station, NJ: Merck.
- ^ S. Hoogewerf and W.A. van Dorp (1885) "Sur un isomére de la quinoléine" (On an isomer of quinoline), Recueil des Travaux Chemiques des Pays-Bas (Collection of Work in Chemistry in the Netherlands), vol.4, no. 4, pages 125–129. See also: S. Hoogewerf and W.A. van Dorp (1886) "Sur quelques dérivés de l'isoquinoléine" (On some derivatives of isoquinoline), Recueil des Travaux Chemiques des Pays-Bas, vol.5, no. 9, pages 305–312.
- ISBN 9783319039794.
- ISBN 9783319039794.
- ISBN 978-1-4612-7375-2.
External links
Encyclopædia Britannica. Vol. 22 (11th ed.). 1911. pp. 758–759.
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