Difference between revisions of "Kaurane"

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'''Kaurane''' is a [[parent hydride]] used in the [[IUPAC nomenclature of natural products]] and also, distinctly, in [[CAS nomenclature]]. It is a [[diterpene]] with a rigid four-ring structure and six [[Chirality|chiral centres]].
 
'''Kaurane''' is a [[parent hydride]] used in the [[IUPAC nomenclature of natural products]] and also, distinctly, in [[CAS nomenclature]]. It is a [[diterpene]] with a rigid four-ring structure and six [[Chirality|chiral centres]].
  
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[[File:Kaurane numbered.png|thumb|right|The conventional numbering of kaurane: for the numbering of the methyl groups and C-18 and C-19, see text.]]
 
The stereochemistry of the six chiral centres is defined by convention: however, IUPAC and CAS use different conventional stereochemistry, which also leads to a slight difference in numbering between the two systems. IUPAC conventional kaurane has (5''S'',8''S'',9''S'',10''S'',13''S'',15''R'')-stereochemistry, and is drawn with the five-membered ring receding into the plane of the image.<ref name="IUPAC">{{IUPAC natural products 1999}}.</ref> CAS conventional kaurane has (5''S'',8''R'',9''S'',10''S'',13''R'',15''R'')-stereochemistry, and is drawn with the five-membered ring protruding from the plane of the image.<ref name="CAS">{{citation | contribution = 57817-89-7 – Kaur-16-en-18-oic acid, 13-&#91;(2-''O''-β-<small>D</small>-glucopyranosyl-β-<small>D</small>-glucopyranosyl)oxy&#93;-, β-<small>D</small>-glucopyranosyl ester, (4α)- | url = http://www.commonchemistry.org/ChemicalDetail.aspx?ref=57817-89-7 | title = Common Chemistry | publisher = Chemical Abstracts Service | accessdate = 2009-09-05}}.</ref> Carbon-19 (one of the two methyl groups attached to carbon-4) is on the same side of the molecule as the five-membered ring in both systems: hence it is receding into the plane of the image in IUPAC nomenclature and protruding from the plane of the image in CAS nomenclature.
 
The stereochemistry of the six chiral centres is defined by convention: however, IUPAC and CAS use different conventional stereochemistry, which also leads to a slight difference in numbering between the two systems. IUPAC conventional kaurane has (5''S'',8''S'',9''S'',10''S'',13''S'',15''R'')-stereochemistry, and is drawn with the five-membered ring receding into the plane of the image.<ref name="IUPAC">{{IUPAC natural products 1999}}.</ref> CAS conventional kaurane has (5''S'',8''R'',9''S'',10''S'',13''R'',15''R'')-stereochemistry, and is drawn with the five-membered ring protruding from the plane of the image.<ref name="CAS">{{citation | contribution = 57817-89-7 – Kaur-16-en-18-oic acid, 13-&#91;(2-''O''-β-<small>D</small>-glucopyranosyl-β-<small>D</small>-glucopyranosyl)oxy&#93;-, β-<small>D</small>-glucopyranosyl ester, (4α)- | url = http://www.commonchemistry.org/ChemicalDetail.aspx?ref=57817-89-7 | title = Common Chemistry | publisher = Chemical Abstracts Service | accessdate = 2009-09-05}}.</ref> Carbon-19 (one of the two methyl groups attached to carbon-4) is on the same side of the molecule as the five-membered ring in both systems: hence it is receding into the plane of the image in IUPAC nomenclature and protruding from the plane of the image in CAS nomenclature.
  

Revision as of 16:53, 5 September 2009

IUPAC
CAS
The two different structures referred to as kaurane.

Kaurane is a parent hydride used in the IUPAC nomenclature of natural products and also, distinctly, in CAS nomenclature. It is a diterpene with a rigid four-ring structure and six chiral centres.

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The conventional numbering of kaurane: for the numbering of the methyl groups and C-18 and C-19, see text.

The stereochemistry of the six chiral centres is defined by convention: however, IUPAC and CAS use different conventional stereochemistry, which also leads to a slight difference in numbering between the two systems. IUPAC conventional kaurane has (5S,8S,9S,10S,13S,15R)-stereochemistry, and is drawn with the five-membered ring receding into the plane of the image.[1] CAS conventional kaurane has (5S,8R,9S,10S,13R,15R)-stereochemistry, and is drawn with the five-membered ring protruding from the plane of the image.[2] Carbon-19 (one of the two methyl groups attached to carbon-4) is on the same side of the molecule as the five-membered ring in both systems: hence it is receding into the plane of the image in IUPAC nomenclature and protruding from the plane of the image in CAS nomenclature.

The name ent-kaurane is sometimes used to refer to the CAS conventional kaurane,[3] and so to distinguish it from the IUPAC stereochemistry, in particular by the International Union of Biochemistry and Molecular Biology (IUBMB).[4] It is also possible to explicitly specify the stereochemistry at carbons 8 and 13, giving:

  • (8S,13S)-kaurane (IUPAC conventional)
  • (8R,13R)-kaurane (CAS conventional)

Kaurane diterpenes have been extracted from a variety of plant species,[3][5] in particular Stevia sp., the source of the steviol glycosides stevioside and rebaudioside-A that have been used as artificial sweetners.[6] They are intermediates on the gibberellic acid pathway to several plant hormones known as gibberellins:[7] gibberellic acid is biosynthesized from ent-kaurene by six successive oxidations catalyzed by ent-kaurene oxidase (EC 1.14.13.78) and ent-kaurenic acid oxidase (EC 1.14.13.79).[4]

References

  1. ↑ Revised Section F: Natural Products and Related Compounds (IUPAC Recommendations 1999). Pure Appl. Chem., 71 (4), 587–643. DOI: 10.1351/pac199971040587.
  2. ↑ 57817-89-7 – Kaur-16-en-18-oic acid, 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy]-, β-D-glucopyranosyl ester, (4α)-. In Common Chemistry; Chemical Abstracts Service, <http://www.commonchemistry.org/ChemicalDetail.aspx?ref=57817-89-7>. (accessed 5 September 2009).
  3. ↑ 3.0 3.1 Nagashima, Fumihiro; Tanaka, Hironao; Takaoka, Shigeru; Asakawa, Yoshinori Ent-kaurane-type diterpenoids from the liverwort Jungermannia exsertifolia ssp. cordifolia. Phytochemistry 1996, 41 (4), 1129–41. DOI: 10.1016/0031-9422(95)00755-5. Arriaga-Giner, Francisco Javier; Rumbero, Angel; Wollenweber, Eckhard 16α,19-Diacetoxy-ent-kaurane, a New Natural Diterpene from the Exudate of Ozothamnus scutellifolius (Asteraceae). Z. Naturforsch. C 1999, 54, 602–4. Ding, Lan; Zhang, Zhang-Jing; Liu, Guo-An; Yang, Dong-Juan; Guo, Guo-Cong; Wang, Han; Sun, Kun Three New Cytotoxic ent-Kaurane Diterpenoids from Isodon weisiensis C. Y. Wu. Helv. Chim. Acta 2005, 88 (9), 2502–7. DOI: 10.1002/hlca.200590185. Batista, Ronan; García, Pablo A.; Castro, Maria A.; del Corral, José M. Miguel; San Feliciano, Arturo; de Oliveira, Alaíde B. New oxidized ent-kaurane and ent-norkaurane derivatives from kaurenoic acid. J. Braz. Chem. Soc. 2007, 18 (3), 622–27. DOI: 10.1590/S0103-50532007000300020. Zhao, Yong; Pu, Jian-Xin; Huang, Sheng-Xiong; Ding, Li-Sheng; Wu, Ying-Li; Li, Xian; Yang, Li-Bin; Xiao, Wei-Lie, et al. ent-Kaurane diterpenoids from Isodon pharicus. J. Nat. Prod. 2009, 72 (6), 988–93. PMID 19425589. DOI: 10.1021/np9000366.
  4. ↑ 4.0 4.1 EC 1.14.13.78 – ent-kaurene oxidase. In ExPASy Proteomics Server; Swiss Institute of Bioinformatics, <http://www.expasy.org/cgi-bin/nicezyme.pl?1.14.13.78>. (accessed 5 September 2009). EC 1.14.13.79 – ent-kaureneic acid oxidase. In ExPASy Proteomics Server; Swiss Institute of Bioinformatics, <http://www.expasy.org/cgi-bin/nicezyme.pl?1.14.13.79>. (accessed 5 September 2009).
  5. ↑ Nagashima, Fumihiro; Kondoh, Masuo; Uematsu, Toshinari; Nishiyama, Akiko; Saito, Sayaka; Sato, Masao; Asakawa, Yoshinori Cytotoxic and apoptosis-inducing ent-kaurane-type diterpenoids from the Japanese liverwort Jungermannia truncata nees. Chem. Pharm. Bull. 2002, 50 (6), 808–13. DOI: 10.1248/cpb.50.808. Bruno, Maurizio; Piozzi, Franco; Arnold, Nelly Apostolides; Başer, K. Hüsnü Can; Tabanca, Nurhayat; Kirimer, Neşe Kaurane Diterpenoids from Three Sideritis Species. Turk. J. Chem. 2005, 29 (1), 61–64, <http://journals.tubitak.gov.tr/chem/issues/kim-05-29-1/kim-29-1-7-0402-1.pdf>. Kim, Ki Hyun; Choi, Sang Un; Lee, Kang Ro Diterpene glycosides from the seeds of Pharbitis nil. J. Nat. Prod. 2009, 72 (6), 1121–27. PMID 19435339. DOI: 10.1021/np900101t.
  6. ↑ Jaitak, Vikas; Bikram Singh, Bandna; Kaul, V. K. An efficient microwave-assisted extraction process of stevioside and rebaudioside-A from Stevia rebaudiana (Bertoni). Phytochem. Anal. 2009, 20 (3), 240–45. PMID 19358287. DOI: 10.1002/pca.1120.
  7. ↑ Brandle, J. E.; Telmer, P. G. Steviol glycoside biosynthesis. Phytochemistry 2007, 68 (14), 1855–63. DOI: 10.1016/j.phytochem.2007.02.010.

Further reading

External links

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