Studies on the Phytoalexin Elicitor-Active Substance for the Defensive Mechanism in Plants

众所周知，一些植物合成抗菌物质作为抵抗入侵微生物的防御机制。这些合成的抗微生物物质被称为植物抗毒素，它们的诱导物被称为诱导子。松原发现了一种对萌发的松孢球腔菌分生孢子培养滤液中的一种糖蛋白具有激发活性，并确定其结构为糖基链。为了详细研究生物活性糖蛋白的结构要求，我们对糖肽模型的三糖基-丝氨酸和/或三糖基二肽衍生物进行了合成研究。二糖，2，3，4，6-四-OMICRON-乙酰基-BETA-D-吡喃葡萄糖基-（1-6）-2，3，4-rei-OMICRON-乙酰基-ALPHA-D-吡喃单糖基三氯乙酰亚胺酸酯与NU-（carbovenzoxy）-2，3，4，-tri-OMICRON-acetyl-ALPHA-D-mannlpyranosyl）-（1-3）-L-serine methyl ester or NU-（苄氧羰基）-（2，3，4，-三-OMICRON-乙酰基-ALPHA-D-吡喃甘露糖基）-（1-3）-L-丝氨酰基-L-脯氨酸甲酯通过使用AgOTf得到所需的三糖-丝氨酸或三糖-丝氨酰基-脯氨酸衍生物，通过去除NU-苄氧羰基，然后脱酰化，将其转化为BETA-D-吡喃葡萄糖基-（1 - 6）-ALPHA-D-吡喃单糖基-（1-6）-PLPHA-D-吡喃单糖基-（1- 3）-L-丝氨酸和三糖基-（1-3）-L-丝氨酰-L-脯氨酸。这些化合物具有潜在的激发子活性。

It is generally known that some plants synthesize antimicrobial substances as a defende mechanism against invasive microorganism. These antimicrovial substances synthesized are called phytoalexins, and their inducer is called an elicitor. Matsubara found elicitor activity on a aglycoprotein in a culture fitrate of germinating Mycospharella pinodes conidia and determined its structure to ve a glycosyl chain. In order to investigate the structural requirements for bioactive glycoprotein in detail, we have carried out synthetic studies on the triglycosyl-serine and/or trihlycosyl dipeptide derivatives of a model of the glycopeptide. Glycosylation of the disaccharide, 2,3,4,6-tetra-OMICRON-acetyl-BETA-D-glucopyranosyl-(1-6)-2,3,4-rei-OMICRON-acetyl-ALPHA-D-monnopyranosyl trichloroacetimidate, with NU-(carbovenzoxy)-2,3,4, -tri-OMICRON-acetyl-ALPHA-D-mannlpyranosyl)-(1-3)-L-serine methyl ester or NU-(carbobenzoxy)-(2,3,4, -tri-OMICRON-acetyl-ALPHA-D-mannopyranosyl)-(1-3)-L-seryl-L-proline methyl ester by use of AgOTf gave the desired trisaccharide-serine or trisaccharide-seryl-proline derivatives, which were transformed into BETA-D-dlucopyranosyl-(1-6)-ALPHA-D-monnopyranosyl-(1-6)-PLPHA-D-monnopyranosyl-(1-3)-L-serine and triglycosyl-(1-3)-L-seryl-L-proline via removal of NU-carbobenzoxy group, followed by deacylation. These compounds possess potenitial elicitor activity.