88(P-12) タバコ野火病原因菌由来の非選択的植物毒素tabtoxinine-β-lactamの合成研究(ポスター発表の部)

概要

論文の詳細を見る
Tobacco wildfire disease, caused by infection of tobacco wildfire disease fungus Pseudomonas tabaci, has been the most serious pest for tobacco, and tabtoxin (1) was isolated from the fungus as a phytopathogenic toxin. 1 is converted by host plant peptidases to tabtoxinine-β-lactam (2), which inactivates glutamine synthetase irreversibly. 1 can be a selective pesticide when crops resistant to 1 are developed. We began the synthetic studies of 2 to supply samples to its biological tests and to develop an efficient synthetic route. Zinc mediated coupling of iodide 4b with ester 6 and silyl ether 9 gave 10b and 13b, respectively. Sharpless asymmetric dihydroxylation of the double bonds of each compound afforded 19b (20-30%de) and 21b (81-91%de), respectively. The primary hydroxy group of the diol 19b was converted to amino group, and magnesium mediated β-lactam formation and deprotection gave 2. However, the diastereomeric selectivity of the dihydroxylation of 19b had not improved. So, we tried the conversion of 21b. Oxidation of the primary hydroxy group of 21b gave acid 32b. The corresponding benzyloxy amide 33b was converted to mesylate 35b. The key β-lactam formation using NaH afforded 36b. The last deprotection steps are now in progress.
天然有機化合物討論会の論文
2003-09-01