80054-40-6Relevant academic research and scientific papers
Stereochemistry of an alcohol oxidase from the defensive secretion of larvae of the leaf beetle Phaedon armoraciae (Coleoptera: Chrysomelidae)
Veith, Martin,Dettner, Konrad,Boland, Wilhelm
, p. 6601 - 6612 (1996)
Larvae of the leaf beetle Phaedon armoraciae produce the iridoids chrysomelidial 1 and plagiodial 3 from geraniol 6 by an oxidative sequence identical to that known in plants. Following ω-oxidation of geraniol the resulting 8-hydroxygeraniol 7 is oxidised via 8-oxogeraniol 14 and 8-hydroxygeranial 15 and to the dialdehyde 8. In plants this transformation is achieved by NADP+ dependent oxidoreductases. However, in the defensive secretion of several leaf beetles an oxygen-dependent oxidase is present. The enzyme catalyses the removal of the C(1)- and C(8)-H(R) hydrogen atoms (Re-specificity) from the diol 7 yielding 8-oxogeranial 8.
Resolution of an iridoid synthon, gastrolactol, by means of dynamic acetylation and lipase-catalyzed alcoholysis
Santangelo,Rotticci,Liblikas,Norin,Unelius
, p. 5384 - 5387 (2001)
A short synthetic route to asymmetric iridoids was developed. The three key steps were an intramolecular [4 + 2] cycloaddition reaction of an enamine derivative of 8-oxocitral (2), a dynamic acetylation, and an enzymatic resolution of the gastrolactyl acetates 5a and 5b, iridoids with three stereocenters. Some regio- and stereoselective heterogeneous catalytic hydrogenations of double bonds in iridoid aglucones were discussed.
Structures of Iridoid Synthase from Cantharanthus roseus with Bound NAD+, NADPH, or NAD+/10-Oxogeranial: Reaction Mechanisms
Hu, Yumei,Liu, Weidong,Malwal, Satish R.,Zheng, Yingying,Feng, Xinxin,Ko, Tzu-Ping,Chen, Chun-Chi,Xu, Zhongxia,Liu, Meixia,Han, Xu,Gao, Jian,Oldfield, Eric,Guo, Rey-Ting
, p. 15478 - 15482 (2015)
Structures of the iridoid synthase nepetalactol synthase in the presence of NAD+, NADPH or NAD+/10-oxogeranial were solved. The 10-oxogeranial substrate binds in a transoid-O1-C3 conformation and can be reduced by hydride addition to form the byproduct S-10-oxo-citronellal. Tyr178 Oζ is positioned 2.5 ? from the substrate O1 and provides the second proton required for reaction. Nepetalactol product formation requires rotation about C1-C2 to form the cisoid isomer, leading to formation of the cis-enolate, together with rotation about C4-C5, which enables cyclization and lactol production. The structure is similar to that of progesterone-5β-reductase, with almost identical positioning of NADP, Lys146(147), Tyr178(179), and F342(343), but only Tyr178 and Phe342 appear to be essential for activity. The transoid 10-oxogeranial structure also serves as a model for β-face hydride attack in progesterone 5β-reductases and is of general interest in the context of asymmetric synthesis.
Biosynthesis of defensive allomones in leaf beetle larvae: Stereochemistry of salicylalcohol oxidation in Phratora vitellinae and comparison of enzyme substrate and stereospecificity with alcohol oxidases from several iridoid producing leaf beetles
Veith,Oldham,Dettner,Pasteels,Boland
, p. 429 - 443 (2007/10/03)
(7S)-[2H5]-Salicylalcohol (3) and (7R)-[2H1]-salicylalcohol (5) have been synthesized in order to examine the stereospecificity of salicylalcohol oxidase from the defensive secretion of the salicylaldehyde-producing leaf beetle Phratora vitellinae. Oxidation was found to proceed by selective removal of the C(7)-H(R) hydrogen atom (Re-specificity) to yield salicylaldehyde. (7S)-[2H6]-Benzylalcohol (9) was also oxidized Re-specifically to benzaldehyde, but in much lower yield, indicating the importance of the orthohydroxy group of salicylalcohol in substrate enzyme binding. The stereospecificities of terpenoid oxidases from six species of iridoid-producing leaf beetle were examined using (1R,8R)-[2H2]-8-hydroxygeraniol (10), and were all found to oxidize the substrate Re-specifically. Cross-activity of oxidation was found in a number of species, with P. vitellinae able to oxidize terpenoid (10) and two of the iridoid-producing species able to oxidize salicylalcohol analogue (3), again with Re-specificity. However, when the two substrate analogs were presented together, in equal concentrations, preferential oxidation of the natural analog was observed in each case. The kinetics of oxidation for a number of terpenoid and aromatic alcohols by the defensive secretion of the iridoid-producing leaf beetle Phaedon armoraciae have been studied, revealing a large difference between the rate of (primary, allylic) terpenoid alcohol oxidation and the rate of salicylalcohol oxidation, thus accounting for the observed selectivity.
The aphid sex pheromone cyclopentanoids: Synthesis in the elucidation of structure and biosynthetic pathways
Dawson, Glenn W.,Pickett, John A.,Smiley, Diane W. M.
, p. 351 - 361 (2007/10/03)
Identification of a range of aphid sex pheromones as comprising the cyclopentanoids (4aS,7S,7aR)-nepetalactone, (1R,4aS,7S,7aR)-nepetalactol and the (1S)- and (1R,4aR,7S,7aS)-nepetalactols required samples authenticated by 1H and 13C NMR. These and related compounds were provided by small scale synthesis and extraction from plants in the genus Nepeta (Lamiaceae). The subsequent discovery that the synthetic sex pheromones could attract males, and also parasitic wasps that attack aphids, has created a need for large scale syntheses of the cyclopentanoids. This is afforded by cyclisation of the 8-oxo-1-enamine of citronellal as originally developed by Schreiber and co-workers (1986). Investigation into the biosynthesis of the cyclopentanoids by plants for exploiting aphid sex pheromones in crop protection by means of molecular biology required synthesis of putative biosynthetic intermediates, some with radioactive isotopic labelling, particularly 8-oxidised monoterpene alcohols and aldehydes.
Investigations of the Biosynthesis of Indole Alkaloids. Feeding Experiments with Synthetic Radioactively Labelled Monoterpene Aldehydes
Battersby, Alan R.,Thompson, Mervyn,Gluesenkamp, Karl-Heinz,Tietze, Lutz-F.
, p. 3430 - 3438 (2007/10/02)
Oxidation of citral (8a/8b) with selenium oxide using different reaction conditions gave the hydroxy aldehydes 4a/4b and the dialdehydes 5a/b.Reduction of 5a/b with potassium borohydride in the presence of LiCl led to the hydroxy aldehyes 4c/d.Feeding experiments with the corresponding tritiated compounds 4a - d and 5a/b to Catharanthus roseus G.Don indicate that 4a/b, 4c/d, and 5a/b are biogenetic precursors of secologanin (3) and the indole alkaloids of the Corynanthe, Aspidosperma, and Iboga type.
