Chemical Studies on Growth Self-inhibitors Produced by Phytopathogenic Fungi.

1. Chloromonilicin是樱桃褐腐真菌Momilinia fructicola产生的一种生长自抑制剂。(1)从M. fructicola，其结构具有一个新的七元内酯环的化学和光谱证据的基础上确定。4-还分离并鉴定了可能是I前体的Chloropinselin（II）。I对植物病原真菌表现出较强的抗真菌活性。(2)通过发酵法制备溴同系物-溴青霉素。此外，还从溴代莫尼来霉素发酵液中分离到一种新的二苯甲酮代谢产物莫尼来苯酮（III）.通过使用氘代III的饲养实验揭示了生物合成途径III-> II-> I。(3)从发酵液中分离得到新的内酯还原催化剂，分别命名为氯青霉酸A和B。它们几乎没有表现出抗菌活性。溴代莫尼兰菌素转化为溴代莫尼兰酸B，后者再转化为溴代莫尼兰酸A。2.果糖其他植物病原真菌产生的生长自抑制物质。(1)从轮纹叶斑病菌Mycosphaerella nawae中分离到两个结构上相关的生长自抑制剂。其中一个化合物经鉴定为（-）-松萝酸异甲醇盐。(2)从樱桃炭疽病菌Glomerella cingulata中分离得到一种生长自抑制物质。活性物质不稳定，甲醇分解得到无活性化合物。

1. Chloromonilicin, a growth self-inhibitor produced by cherry brown fungus Momilinia fructicola.(1) A new growth self-inhibitor, chloromonilicin (I), was isolated from M. fructicola, and its structure having a novel seven-membered lactone ring was determined on the basis of chemical and spectroscopic evidence. 4-Chloropinselin (II), a probable precursor of I, was also isolated and identified. I showed strong antifungal activity against phytopathogenic fungi.(2) The bromine congener, bromomonilicin, was prepared by fermentation. In addition, moniliphenone (III), a new benzophenone metabolite, was isolated from the bromomonilicinfe- fermentation broth. The biosynthetic pathway, III-> II-> I, was revealed by feeding experiments using deuterated III.(3) Novel lactone-reduced catabolites of I, which were named chloromonilinic acids A and B, were isolated from the chloromonilicin-fermrntation broth. They hardly showed antimicrobial activity. Bromomonilicin was transformed into bromomonilinic acid B, and then the latter into bromomonilinic acid A by M. fructicola.2. Growth self-inhibiting substances produced by other phytopathogenic fungi.(1) Two structurally related growth self-inhibitors were isolated form circular leaf spot fungus Mycosphaerella nawae. One of them was identified as (-)-usnic acid isomethoxide.(2) A growth self-inhibiting substance was obtained from cherry anthracnose fungus Glomerella cingulata. The active substance was unstable, and gave an inactive compound by methanolysis.