Lysergic acid received its name as it was a product of the lysis of various ergot alkaloids.[4]
Synthesis
Laboratory
Lysergic acid is generally produced by hydrolysis[5] of natural lysergamides, but can also be synthesized in the laboratory by a complex total synthesis, for example by Robert Burns Woodward's team in 1956.[6] An enantioselective total synthesis based on a palladium-catalyzed domino cyclization reaction has been described in 2011 by Fujii and Ohno.[7] Lysergic acid monohydrate crystallizes in very thin hexagonal leaflets when recrystallized from water. Lysergic acid monohydrate, when dried (140 °C at 2 mmHg or 270 Pa) forms anhydrous lysergic acid.
Biosynthesis
The biosynthetic route is based on the alkylation of the amino acid tryptophan with dimethylallyl diphosphate (isoprene derived from 3R-mevalonic acid) giving 4-dimethylallyl-L-tryptophan which is N-methylated with S-adenosyl-L-methionine. Oxidative ring closure followed by decarboxylation, reduction, cyclization, oxidation, and allylic isomerization yields D-(+)-lysergic acid.[4] The biosynthetic pathway has been reconsituted in transgenic baker's yeast.[8]
Isomers
Lysergic acid is a chiral compound with two stereocenters. The isomer with inverted configuration at carbon atom 8 close to the carboxyl group is called isolysergic acid. Inversion at carbon 5 close to the nitrogen atom leads to L-lysergic acid and L-isolysergic acid, respectively.
^Brown, H. C.; et al. (1955). Braude, E. A.; Nachod, F. C. (eds.). Determination of Organic Structures by Physical Methods. New York, NY: Academic Press.
^Martínková, L.; Kren, V.; Cvak, L.; Ovesná, M.; Prepechalová, I. (Nov 17, 2001). "Hydrolysis of lysergamide to lysergic acid by Rhodococcus equi A4". J. Biotechnol. 84 (1): 63–6. doi:10.1016/s0168-1656(00)00332-1. PMID11035188.
^Kornfeld, Edmund C.; Fornefeld, E. J.; Kline, G. Bruce; Mann, Marjorie J.; Morrison, Dwight E.; Jones, Reuben G.; Woodward, R. B. (1956). "The Total Synthesis of Lysergic Acid". J. Am. Chem. Soc. 78 (13): 3087–3114. doi:10.1021/ja01594a039.
^Inuki, S.; Iwata, A.; Oishi, S.; Fujii, N.; Ohno, H. (2011). "Enantioselective Total Synthesis of (+)-Lysergic Acid, (+)-Lysergol, and (+)-Isolysergol by Palladium-Catalyzed Domino Cyclization of Allenes Bearing Amino and Bromoindolyl Groups". J. Org. Chem. 76 (7): 2072–2083. doi:10.1021/jo102388e. PMID21361331.