Phytoalexin elicitors

Scheme 4.21 Mukaiyama s one-pot synthesis of phytoalexin-elicitor active heptasaccharide.

In 1997 Nicolaou et al. published the assembly of a heptasaccharide phytoalexin elicitor (HPE, 16) on a solid support (Schemes 5.2-5.4).29 This oligosaccharide... 

Scheme 5.4 Photolytic cleavage of resin-bound heptasaccharide 15 and deprotection to yield the heptasaccharide phytoalexin elicitor 16.29...

P. FOgedi, W. Birberg, P. J. Garegg, and A. Pilotti, Synthesis of a branched heptasaccharide having phytoalexin-elicitor activity, Carbokydr. Res 164 797 (1987). 

Filippini, F., Lo Schiavo, F., Terzi, M., Branca, C., Bellincampi, D., Salvi, G., Desiderio, A., de Lorenzo, G., Cervone, F. (1992). Phytoalexin elicitor-active a-l,4-D-oligogalacturonides reduce auxin perception by plant cells and tissues. Progress in Plant Growth Regulation (Karssen, C.M., Van Loon, L.C., Vreugdenhil, D., Eds.), pp. 517-521. Kluwer Academic, The Netherlands. 

Borie B, Jeandet P, Parize A, Bessis R, Adrian M. 2004. Resveratrol and stylbene synthase mRNA production in grapevine leaves treated with biotic and abiotic phytoalexin elicitors. Am J Enol Vitic 55 160-164. 

Takeuchi, Y., Yoshikawa, M., Takeba, G., Kunisuke, T., Shibata, D. Florino, O. (1990). Molecular cloning and ethylene induction of mRNA encoding a phytoalexin elicitor-releasing factor P-l,3-glu-canase, in soybean. Plant Physiology 93, 673-82. 

The phytoalexin elicitor (PE) family of /1-D-glucans (Fig. 5) was selected as a target because these oligosaccharides had been synthesized previously in solution48,49 and on the solid support.50,51 It was our intention to investigate not only the application of glycosyl phosphates to automated solid-phase synthesis, but also to compare our method to the previously described reports of PE syntheses. 

Nicolau, K. C., Winssinger, N., Pastor, J., and DeRoose, F. (1997) A general and highly efficient solid phase synthesis of oligosaccharides. Total synthesis of a heptasaccharide phytoalexin elicitor (HPE)../. Am. Chem. Soc. 119,449—450. 

The addition of a second, reducing end acceptor and a thiophilic promoter (NIS) resulted in trisaccharide formation. Yields as high as 84% for the overall process were reahzed, showcasing the efficiency of this strategy as well as the promoter compatibility, which can be a problem (Fig. 3). The method has been extended to branched structures as well (34). Takahashi has advanced the orthogonal OPG strategy in an impressive synthesis of the heptasaccharide phytoalexin elicitor (HPE) in 24% overall yield (35). 

GA, van Boom JH. Polymer-supported solution synthesis of a heptaglucoside having phytoalexin elicitor activity. Reel. Trav. 94. 

SCHEME 27. Steric hindrance-facilitated synthesis157 of phytoalexin-elicitor active oligosaccharide 149. 

R. Geurtsen, F. Cote, M. G. Hahn, and G.-J. Boons, Chemoselective glycosylation strategy for the convergent assembly of phytoalexin-elicitor active oligosaccharides and their photoreactive derivatives, /. Org. Chem., 64 (1999) 7828-7835. 

The second example is a solid-phase synthesis of a heptasaccharide phytoalexin elicitor. Here, attachment of the polymer was to the reducing end of the oligosaccharide. The structure was chosen as an example for the development of... 

Eilert et al. (95) reported the treatment of five different cell lines of C. roseus with homogenates of various fungi as well as with chemically defined phytoalexin elicitors. It was found that a Pythium aphanider-matum homogenate concentration of 5% and a Rhodotorula rubra homogenate concentration of 0.5% affected alkaloid yields. The response of the cells to elicitor treatment revealed a temporary increase of alkaloid content in the cells and in the culture medium 12-24 hr following addition. 

Scheme 7. Automated solid phase synthesis of a protected phytoalexin elicitor.

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