Chemistry:Abietic acid

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Abietic acid
Names
IUPAC name
Abieta-7,13-dien-18-oic acid
Systematic IUPAC name
(1R,4aR,4bR,10aR)-1,4a-Dimethyl-7-(propan-2-yl)-1,2,3,4,4a,4b,5,6,10,10a-decahydrophenanthrene-1-carboxylic acid
Other names
Abietinic acid; Sylvic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
EC Number
  • 208-173-3
KEGG
RTECS number
  • TP8580000
UNII
Properties
C20H30O2
Molar mass 302.458 g·mol−1
Appearance Colorless solid
Density 1.06 g/mL
Melting point 172–175 °C (342–347 °F; 445–448 K)[1]
Insoluble[1]
Solubility in other solvents Very soluble in acetone, petroleum ether, Et2O, and ethanol
Hazards
Main hazards Irritant
Safety data sheet MSDS
GHS pictograms GHS07: Harmful
GHS Signal word Warning
H317
P261, P272, P280, P302+352, P321, P333+313, P363, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondFlammability code 0: Will not burn. E.g. waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Tracking categories (test):

Abietic acid (also known as abietinic acid or sylvic acid) is a diterpenoid found in coniferous trees. It is supposed to exist to defend the host plant from insect attack or various wounds. Chemically, it is a complicated molecule featuring two alkene groups and a carboxylic acid within a chiral tricyclic framework. As the major component of rosin, it is commercially important. Historically speaking, it was a major component of naval stores. It is the most common of the resin acids. Another common resin acid is pimaric acid, which converts to abietic acid upon heating.

Characteristics and occurrence

Abietic acid is found in rosin obtained from pine trees.[2] Pure abietic acid is a colorless solid, but commercial samples are usually a glassy or partly crystalline yellowish solid that melts at temperatures as low as 85 °C (185 °F).[3] Abietic acid is soluble in alcohols, acetone, and ethers. Its esters and salts are called an abietates, e.g. ethyl abietate and sodium abietate.[4]

The ancient presence of abietic acid (and other resin acids), being abundant and resilient, can inferred by analysis of rocks and archeological samples. Through the process of diagenesis, abietic acid changes into a collection of simpler compounds called abietanes.

Biosynthesis

Route from copalyl pyrophosphate to abietadiene, precursor to abietic acid (PP = pyrophosphate).

Abietic acid is derived from the diterpene abietadiene, which in turn is made from copalyl pyrophosphate (CPP), which is derived from geranylgeranyl pyrophosphate ( GGPP), the precursor to many diterpenoids. In air and in the presence of certain cytochrome P450 enzymes, abietadiene is oxidized to abietic acid. An entire family of so-called resin acids form similarly. Together with abietic acid, these resin acids are a major portion of rosin, the solid portion of the oleoresin of coniferous trees.

Abietenes are synthesized from geranylgeranyl diphosphate via a copalyl diphosphate intermediate by class 2 diterpene cyclases and class 1 diterpene syntheses.[5]

The conformation of the GGPP molecule dictates the stereochemistry of the CPP intermediate after cyclization. The stereochemistry of the typical abietane skeleton suggests a GGPP precursor with its fused cyclohexyl rings in a chair-chair ("normal") conformation, although some abietanes with alternative stereochemistry may be cyclized from CCP isomers containing alternative combinations of boat 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 methyl migration and dehydrogenation steps yield the abietene isomers.[5]

Preparation

Abietic acid is extracted from tree rosin. Laboratory procedures illustrate the nature of the extraction, which is the basis of a substantial industry, formerly known as naval stores.[6]

Uses

As a component of rosin and one of the principal resin acids, abietic acid has many uses, e.g. in some paints, soaps, foods, soldering flux,

Safety

  • Abietic acid is considered a "nonhazardous natural substance" in tall oil ("liquid rosin").[4]
  • In the U.S., abietic acid is listed in the inventory of the Toxic Substances Control Act.
  • Abietic acid is the primary irritant in pine wood and resin. As a contact allergen[7] it is the cause of abietic acid dermatitis. (However, compounds resulting from its oxidation by air elicit stronger responses.) [8]
  • 50% ethanol extracts from Resina pini of Pinus sp. (Pinaceae) showed inhibitory activity against testosterone 5α-reductase prepared from rat prostate. The fraction responsible for this activity was purified, and the active constituent was isolated and identified as abietic acid, which exhibited potent inhibitory activity against testosterone 5α-reductase in vitro.[9]

References

  1. ↑ 1.0 1.1 Merck Index, 12th Edition, 3. Abietic Acid
  2. ↑ "Abietic Acid". Dr. Duke's Phytochemical and Ethnobotanical Databases. http://www.ars-grin.gov/cgi-bin/duke/chemical.pl?ABIETICACID. Retrieved 13 January 2012. 
  3. ↑ Hoiberg, Dale H., ed (2010). "abietic acid". Encyclopædia Britannica. I: A-ak Bayes (15th ed.). Chicago, Illinois: Encyclopædia Britannica Inc.. pp. 32. ISBN 978-1-59339-837-8. https://archive.org/details/newencyclopaedia2009ency/page/32. 
  4. ↑ 4.0 4.1 Lars-Hugo Norlin "Tall Oil" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a26_057
  5. ↑ 5.0 5.1 Peters, Reuben J. (2010). "Two rings in them all: The labdane-related diterpenoids". Natural Product Reports 27 (11): 1521–1530. doi:10.1039/c0np00019a. ISSN 0265-0568. PMID 20890488. PMC 3766046. http://dx.doi.org/10.1039/c0np00019a. 
  6. ↑ G. C. Harris and T. F. Sanderson (1963). "Abietic Acid". Organic Syntheses 32: 1. doi:10.15227/orgsyn.032.0001. 
  7. ↑ El Sayed, F; Manzur, F; Bayle, P; Marguery, MS; Bazex, J (1995). "Contact urticaria from abietic acid". Contact Dermatitis 32 (6): 361–2. doi:10.1111/j.1600-0536.1995.tb00628.x. PMID 7554886. 
  8. ↑ Hausen, BM; Krohn, K; Budianto, E (1990). "Contact allergy due to colophony (VII). Sensitizing studies with oxidation products of abietic and related acids". Contact Dermatitis 23 (5): 352–8. doi:10.1111/j.1600-0536.1990.tb05171.x. PMID 2096024. 
  9. ↑ Seong-Soo Roh, Moon-Ki Park and Yong-ung Kim (2010). "Abietic Acid from Resina Pini of Pinus Species as a Testosterone 5α-Reductase Inhibitor". J. Health Sci. 56 (4): 451–455. doi:10.1248/jhs.56.451. 



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