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Revision as of 19:42, 16 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 473965417 of page Abietane for the Chem/Drugbox validation project (updated: 'CASNo').		Latest revision as of 10:51, 24 January 2024 edit Maxim Masiutin (talk | contribs)Extended confirmed users, IP block exemptions, Pending changes reviewers30,619 edits Used lowercase "cite" template everywhere for consistency.
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	{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}}
	{{Chembox		{{Chembox
			| Verifiedfields = changed
⚫	| verifiedrevid = 455530742
			| Watchedfields = changed
⚫	| ImageFile = Abietane.svg
		⚫	| verifiedrevid = 477237178
⚫	| ImageSize = 200px
		⚫	| ImageFile = Abietane.svg
⚫	| IUPACName =
		⚫	| ImageSize = 200px
⚫	| OtherNames = 13α-Isopropylpodocarpane
		⚫	| IUPACName = Abietane
⚫	| Section1 = {{Chembox Identifiers
			| SystematicName = (4a''R'',4b''S'',7''S'',8a''S'',10a''S'')-1,1,4a-Trimethyl-7-(propan-2-yl)tetradecahydrophenanthrene
	| CASNo = <!-- blanked - oldvalue: 19407-12-6 -->
		⚫	| OtherNames = 13α-Isopropylpodocarpane
⚫	| CASNo_Ref = {{cascite|correct|??}}
		⚫	| Section1 = {{Chembox Identifiers
⚫	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
			| CASNo = 19407-12-6
		⚫	| CASNo_Ref = {{cascite|changed|??}}
		⚫	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChI = 1S/C20H36/c1-14(2)15-7-9-17-16(13-15)8-10-18-19(3,4)11-6-12-20(17,18)5/h14-18H,6-13H2,1-5H3/t15-,16-,17-,18-,20+/m0/s1		| StdInChI = 1S/C20H36/c1-14(2)15-7-9-17-16(13-15)8-10-18-19(3,4)11-6-12-20(17,18)5/h14-18H,6-13H2,1-5H3/t15-,16-,17-,18-,20+/m0/s1
	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}		| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChIKey = STIVVCHBLMGYSL-ZYNAIFEFSA-N		| StdInChIKey = STIVVCHBLMGYSL-ZYNAIFEFSA-N
	| PubChem = 6857485		| PubChem = 6857485
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 5256821		| ChemSpiderID = 5256821
	| ChEBI_Ref = {{ebicite|correct|EBI}}		| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 35673		| ChEBI = 35673
	| SMILES = 12(C(C(C)C)CC2)()CC3()C(C)(C)CCC31C		| SMILES = 12(C(C(C)C)CC2)()CC3()C(C)(C)CCC31C
	}}		}}
	| Section2 = {{Chembox Properties		| Section2 = {{Chembox Properties
	| C=20|H=36		| C=20 | H=36
	| Appearance =		| Appearance =
	| Density =		| Density = 0.876 g/ml
	| MeltingPt =		| MeltingPtC =
	| BoilingPt =		| BoilingPt = 338
	| Solubility =		| Solubility =
	}}		}}
	| Section3 = {{Chembox Hazards		| Section3 = {{Chembox Hazards
	| MainHazards =		| MainHazards =
	| FlashPt =		| FlashPt =
	| Autoignition =		| AutoignitionPt =
	}}		}}
	}}		}}
			'''Abietane''' is a ] that forms the structural basis for a variety of ] such as ],<ref>{{cite journal | author = San Feliciano, Arturo | author2 = Gordaliza, Marina | author3 = Salinero, Miguel A. | author4 = Miguel del Corral, Jose M | title = Abietane acids: sources, biological activities, and therapeutic uses | journal = Planta Medica | year = 1993 | volume = 59 | issue = 6 | pages = 485–490 | doi = 10.1055/s-2006-959744 | pmid = 8302943| doi-access = free }}</ref> ], and ] which are collectively known as '''abietanes''' or '''abietane diterpenes'''.
			Abietanes are found in the tissues and resins of certain higher plants, particularly ]s.<ref name=":2">{{cite journal|last1=Otto|first1=A.|last2=Walther|first2=H.|last3=Püttmann|first3=W.|date=January 1997|title=Sesqui- and diterpenoid biomarkers preserved in Taxodium-rich Oligocene oxbow lake clays, Weisselster basin, Germany|url=http://dx.doi.org/10.1016/s0146-6380(96)00133-7|journal=Organic Geochemistry|volume=26|issue=1–2|pages=105–115|doi=10.1016/s0146-6380(96)00133-7|bibcode=1997OrGeo..26..105O |issn=0146-6380}}</ref><ref name=":1">{{cite journal|date=2012-05-15|title=Distribution and carbon isotope patterns of diterpenoids and triterpenoids in modern temperate C3 trees and their geochemical significance|url=https://www.sciencedirect.com/science/article/abs/pii/S0016703712001032|journal=Geochimica et Cosmochimica Acta|language=en|volume=85|pages=342–356|doi=10.1016/j.gca.2012.02.016|issn=0016-7037|last1=Diefendorf|first1=Aaron F.|last2=Freeman|first2=Katherine H.|last3=Wing|first3=Scott L.|bibcode=2012GeCoA..85..342D}}</ref> Although the functions of terpenes are not fully understood, ]s appear to produce abietane diterpenoids as a form of defense against insect and microbial attack.<ref name=":6">{{Citation|last1=Freeman|first1=K.H.|title=Biomarkers for Terrestrial Plants and Climate|date=2014|url=http://dx.doi.org/10.1016/b978-0-08-095975-7.01028-7|work=Treatise on Geochemistry|pages=395–416|publisher=Elsevier|isbn=978-0-08-098300-4|access-date=2021-05-10|last2=Pancost|first2=R.D.|doi=10.1016/b978-0-08-095975-7.01028-7}}</ref><ref>{{cite journal|last1=Mason|first1=Charles J.|last2=Klepzig|first2=Kier D.|last3=Kopper|first3=Brian J.|last4=Kersten|first4=Philip J.|last5=Illman|first5=Barbara L.|last6=Raffa|first6=Kenneth F.|date=June 2015|title=Contrasting Patterns of Diterpene Acid Induction by Red Pine and White Spruce to Simulated Bark Beetle Attack, and Interspecific Differences in Sensitivity Among Fungal Associates|url=http://link.springer.com/10.1007/s10886-015-0588-4|journal=Journal of Chemical Ecology|language=en|volume=41|issue=6|pages=524–532|doi=10.1007/s10886-015-0588-4|pmid=26003180|bibcode=2015JCEco..41..524M |s2cid=1506353 |issn=0098-0331}}</ref> Some abietane diterpenoids, especially aromatic abietenes, are of interest to the ] and ]s communities for their potential biological activities.<ref name=":9" /> In the rock record, abietanes are commonly found in ] as well as in ], sometimes in the form of the mineral ]. Additionally, abietanes are observed in sediments—both riverine and marine—and in ]s, where they are often interpreted as geochemical biomarkers for terrestrial input from conifers.<ref name=":2" /><ref name=":3">{{cite journal|last1=Simoneit|first1=Bernd R.T.|last2=Grimalt|first2=J.O.|last3=Wang|first3=T.G.|last4=Cox|first4=R.E.|last5=Hatcher|first5=P.G.|last6=Nissenbaum|first6=A.|date=January 1986|title=Cyclic terpenoids of contemporary resinous plant detritus and of fossil woods, ambers and coals|url=http://dx.doi.org/10.1016/s0146-6380(86)80025-0|journal=Organic Geochemistry|volume=10|issue=4–6|pages=877–889|doi=10.1016/s0146-6380(86)80025-0|bibcode=1986OrGeo..10..877S |issn=0146-6380}}</ref><ref name=":6" /><ref name=":4" /><ref name=":0" />
			== Chemical structure and properties ==
			]
			Abietanes are tricyclic 20-carbon ] characterized by three fused six-membered rings and alkyl functional groups at carbons 4, 10, and 13. In higher plants, abietanes and other ] are synthesized from four five-carbon ] units. Abietanes are generally nonpolar, volatile, and less dense than ]. The presence of one or more polar functional groups (typically a ] or ]) tends to increase the polarity and boiling point of a given abietane relative to its unsubstituted hydrocarbon form.
			== Biological sources and synthesis ==
			]
			In higher plants, abietanes are synthesized from ] (GGPP) via a copalyl diphosphate (CPP) intermediate. First, GGPP is cyclized by a class II diterpene cyclase enzyme to CPP. The conformation of the GGPP molecule dictates the ] of the CPP intermediate after cyclization. The ] of the typical abietane skeleton suggests a GGPP precursor with its fused ] rings in a ]-chair ("normal") conformation, although some abietanes with alternative ] may be cyclized from CCP isomers containing alternative combinations of ] and chair cyclohexane conformers. After the initial cyclization to CPP, which forms rings A and B in the abietane skeleton, the C ring is formed with the help of a class I diterpene synthase enzyme. Subsequent ] and ] steps yield the abietene isomers.<ref name=":5" />
			== Preservation and diagenesis ==
			]
			]
			] transformation of biomolecules is not fully understood, but several broad diagenetic patterns are hypothesized to affect the transformation of abietanes as they are heated and pressurized in sediments. The first of these patterns is defunctionalization. In particular, the reducing conditions of diagenesis are believed to cause abietanes to lose oxygen-containing functional groups, including ]s and ], as well as ]s.<ref name=":4">{{cite book|last=Killops|first=S. D.|url=https://www.worldcat.org/oclc/27895324|title=An introduction to organic geochemistry|date=1993|publisher=Longman Scientific & Technical|others=V. J. Killops|isbn=0-582-08040-1|location=Harlow, Essex, England|oclc=27895324}}</ref> In addition to defunctionalization, abietanes likely undergo dehydrogenation and aromatization reactions to form more energetically stable systems of ] in their characteristic three ring structure. The hypothesized diagenetic pathway of ] is illustrative of these general patterns. ] is dehydrogenated to dehydroabietic acid, which then loses its carboxylic acid functional group to become dehydroabietin. Loss of the 5-Me group and further dehydrogenation form the aromatic 1,2,3,4-tetrahydroretene molecule. Final aromatization produces ], a common biomarker molecule observed in sedimentary samples.<ref name=":4" />
			== Measurement techniques ==
			Abietanes found in modern gymnosperm resins as well as in the rock record are separated and characterized by ] (GC-MS). Because polar functional groups reduce molecular volatility and make separation by ] difficult, abietane derivatives containing ] and ] moieties are often derivatized with ] groups by treatment with ] prior to GC-MS analysis.<ref name=":7">{{cite journal|last1=Azemard|first1=Clara|last2=Menager|first2=Matthieu|last3=Vieillescazes|first3=Catherine|date=2016-09-01|title=Analysis of diterpenic compounds by GC-MS/MS: contribution to the identification of main conifer resins|url=https://doi.org/10.1007/s00216-016-9772-9|journal=Analytical and Bioanalytical Chemistry|language=en|volume=408|issue=24|pages=6599–6612|doi=10.1007/s00216-016-9772-9|pmid=27449645|s2cid=8264935 |issn=1618-2650}}</ref> More oxidized abietane derivatives have been studied using thermally assisted methylation using ] (TMAH) followed by GC-MS analysis.<ref name=":8" /> MS-MS analysis has been used to elucidate fragmentation mechanisms for mass spectrum peaks of interest.<ref name=":7" /> Mass spectra for ] and some other common abietanes are publicly available in the ] database.<ref>{{cite web|title=Abietic acid|url=https://webbook.nist.gov/cgi/cbook.cgi?ID=C514103&Mask=200#Mass-Spec|access-date=2021-05-22|website=webbook.nist.gov|language=en}}</ref> The spectrum for ] possesses characteristic peaks at m/z = 256 and 241.<ref name=":7" />
			== Use as a biomarker ==
			Abietanes preserved in geological settings are typically interpreted to derive from ]s, specifically ]s.<ref name=":0" /><ref name=":4" /><ref name=":6" /> Although both modern angiosperms and modern gymnosperms synthesize terpenoids, gymnosperm tissues tend to contain significantly higher terpenoid concentrations than angiosperm tissues.<ref name=":1" /> Additionally, the relative abundances of di-, tri-, and penta-cyclic ] varies between gymnosperms and angiosperms. Although some angiosperm families (notably ], ] and ]) are also known to produce abietanes, in general, tricyclic diterpenoids, including abietanes, are much more abundant in gymnosperms.<ref name=":1" /><ref name=":2" /> For these reasons, and because conifers produce significant biomass relative to other gymnosperms, abietanes preserved in geological settings are typically interpreted as conifer biomarkers. It is important to note, however, that such interpretations rely on the assumption that terpenoid distributions and abundances in ancient plants were similar to those in modern plants. Loss of more volatile ]- and ] during diagenetic heating may help explain the different relative abundance of ], including abietanes, in ancient resins and the rock record compared to modern conifer samples.<ref name=":0">{{Citation|title=Source- and age-related biomarker parameters|date=2004-12-16|url=http://dx.doi.org/10.1017/cbo9781107326040.004|work=The Biomarker Guide|pages=483–607|publisher=Cambridge University Press|doi=10.1017/cbo9781107326040.004|isbn=978-0-521-83762-0|access-date=2021-05-10}}</ref>
			=== Examples from archaeology ===
			* Abietenes from ], tar, and pitch have been identified in caulking used on ancient ships.<ref name=":0" />
			* Abietanes have been used to identify conifer resins associated with Egyptian mummies.<ref name=":0" />
			* The ratio of oxidation products of abietanes including dehydroabietic acid and de-7-oxo-dehydroabietic acid and 15-hydroxyl-7-oxo-dehydroabietic acid have been used to estimate the oxidation state of varnish on ] famous painting, "]."<ref name=":8">{{cite journal|date=1997-08-01|title=Analysis of oxidised diterpenoid acids using thermally assisted methylation with TMAH|url=https://www.sciencedirect.com/science/article/abs/pii/S0165237097000582|journal=Journal of Analytical and Applied Pyrolysis|language=en|volume=43|issue=1|pages=41–57|doi=10.1016/S0165-2370(97)00058-2|issn=0165-2370|last1=Pastorova|first1=I.|last2=Van Der Berg|first2=K.J|last3=Boon|first3=J.J|last4=Verhoeven|first4=J.W}}</ref>
			=== Examples from geochemistry ===
			* Carbon isotopic measurements of abietanes and other di- and tri-terpenoids have been made in modern plants, as well as in ancient samples, where they reveal a carbon isotope excursion during the ] (PETM).<ref name=":1" /><ref>{{cite journal|last1=Schouten|first1=Stefan|last2=Woltering|first2=Martijn|last3=Rijpstra|first3=W. Irene C.|last4=Sluijs|first4=Appy|last5=Brinkhuis|first5=Henk|last6=Sinninghe Damsté|first6=Jaap S.|date=June 2007|title=The Paleocene–Eocene carbon isotope excursion in higher plant organic matter: Differential fractionation of angiosperms and conifers in the Arctic|url=http://dx.doi.org/10.1016/j.epsl.2007.04.024|journal=Earth and Planetary Science Letters|volume=258|issue=3–4|pages=581–592|doi=10.1016/j.epsl.2007.04.024|bibcode=2007E&PSL.258..581S |hdl=1874/385783 |s2cid=129625887 |issn=0012-821X|hdl-access=free}}</ref>
			*Abietanes found in marine sediments have been used as evidence of ancient terrigenous input.<ref>{{cite journal|last=Simoneit|first=Bernd R.T|date=April 1977|title=Diterpenoid compounds and other lipids in deep-sea sediments and their geochemical significance|url=http://dx.doi.org/10.1016/0016-7037(77)90285-x|journal=Geochimica et Cosmochimica Acta|volume=41|issue=4|pages=463–476|doi=10.1016/0016-7037(77)90285-x|bibcode=1977GeCoA..41..463S |issn=0016-7037}}</ref>
			*Abietane diterpenoids have been attributed to resinous vascular plants in samples dating to the ].<ref name=":3"/>
			== See also ==
			* ]
			* ]
			*]
			*]
			*]
			*]
			==References==
			{{reflist}}
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