- Irigermanal and Iridogermanal: Two New Triterpenoids from Rhizomes of Iris germanica L.
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α-Irigermanal (8a), γ-irigermanal (8b), and iridogermanal (12) are the major extractable lipids of the rhizomes of Iris germanica, constituting about 1percent of their fresh weight.The structure of the compounds was determined by detailed spectral analysis, chemical degradation, and X-ray crystallography. 8b crystallizes as a methanol solvate in the space group P21 with a = 13.05 (1) Angstroem, b = 8.84 (2) Angstroem, c = 13.78 (1) Angstroem, β = 105.84 (5) deg, and Z = 2.The irigermanals are the first known bicyclic triterpenoids, and iridogermanal is the firstmonocyclic triterpenoid found so far.The compounds are closely related to ambreine.
- Marner, Franz-Josef,Krick, Wolfgang,Gellrich, Bernhard,Jaenicke, Lothar,Winter, Werner
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- STEREOCHEMISTRY OF THE CYCLIZATION OF PSEUDOIRONE AT ELEVATED TEMPERATURE
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The cyclization of pseudoirone (6,9,10-trimethyl-3,5,9-undecatrien-2-one) in the presence of a catalytic amount of phosphoric acid at 110 deg C gives a high yield and leads to the preferential formation of α-irone.It was established that if the reaction was conducted in the presence of protic acids 1-(1,3,4-trimethyl-3-cyclohexenyl)-1-penten-4-one was formed in addition to the α, β, and γ isomers.
- Kron, A. A.,Fedotova, Z. M.,Novikov, N. A.
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p. 534 - 536
(2007/10/02)
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- Internal Nucleophilic Termination in Acid-Mediated Polyene Cyclisations: Synthetic Access to Methyl Homologs of (+/-)-Ambrox and its Diastereoisomers
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Treatment of ten monocyclic dienols 8-11 with an excess of fluorosulfonic acid in 2-nitropropane at -90 deg C afforded diastereoisomeric mixtures of racemic tricyclic ethers 12-14 in 81-91percent yield (see Tables 1 and 2).These transformations represent
- Snowden, Roger L.,Eichenberger, Jean-Claude,Giersch, Wolfgang,Thommen, Walter,Schulte-Elte, Karl H.
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p. 1608 - 1618
(2007/10/02)
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