- The pheromone system of the male danaine butterfly, Idea leuconoe
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Male Idea leuconoe butterflies release a complex mixture of volatiles from their pheromone glands (hairpencils) during courtship. The pheromone components geranyl methyl thioether (2), viridifloric β-lactone (3) and 6-hydroxy-4-dodecanolide (10) have been synthesized for the first time. Therefore, the structural assignment of these new natural products could be proved. Related 7-hydroxy-5-alkanolides are also present in the extract. The volatiles are embedded in a lipidic matrix with more than 150 components. This matrix consists of alkanes, alkenes, 2,5-dialkyltetrahydrofurans, secondary alkanols and alkenols as well as alkanones and alkenones. Several regioisomers of the oxidized hydrocarbons occur. The elucidation of double bond positions has been performed by MS using DMDS adducts.
- Schulz,Nishida
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p. 341 - 349
(2007/10/03)
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- Synthesis of pyrrolizidine alkaloids indicine, intermedine, lycopsamine, and analogues and their N-oxides. Potential antitumor agents
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(-)- and (+)-trachelanthic and (-)- and (+)-viridifloric acids were synthesized and their isopropylidene derivatives were regiospecifically coupled, at C-9, with (-)-retronecine (2) obtained by hydrolysis of monocrotaline (1), isolated from Crotalaria spectabilis. Hydrolysis, followed by oxidation, led to the N-oxides of indicine (7), intermedine (13), lycopsamine (15), and the new nonnatural product 16, respectively. Each of these analogues was screened in the P388 lymphocytic leukemia system at the same time as indicine N-oxide, and the results were compared. Other related analogues were prepared and similarly screened and the results compared with those from indicine N-oxide.
- Zalkow,Glinski,Gelbaum,Fleischmann,McGowan,Gordon
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p. 687 - 694
(2007/10/02)
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- STEREOSELECTIVE REDUCTION OF α-ALKOXY-β-KETO ESTERS. SYNTHESIS OF (+/-)-TRACHELANTHIC ACID AND (+/-)-VIRIDIFLORIC ACID.
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Reduction of the isopropylidene derivative of α-hydroxy-α-isopropyl-β-keto-butyric acid 2b with potassium tri(sec.-butyl)-borohydride and zinc borohydride followed by hydrolysis stereoselectivity produces (+/-)-trachelanthic acid, 3, and (+/-)-viridifloric acid, 4, respectively.
- Glass, Richard S.,Shanklin, Michael
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p. 545 - 552
(2007/10/02)
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