57 植物毒Cyl-2のアナローグ合成と立体構造

概要

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Cyl-2 inhibits the root growth of lettuce seedlings, and its structure is shown to be a cyclotetrapeptide (1). The configuration of Ape residue in 1 is unknown. We synthesized simple analogs, 2, 3, 4, And 5. In case of 2, a dipeptide derivative 6 was synthesized at first and peptide bonds were extended to both N and C directions. Compound 13 was subjected to cyclization reaction and yielded monomer 2 (50%). Other analogs were prepared similarly, silica gel chromatography being used for purification. ^1H-n.m.r. spectra of 2, 4, and natural Cyl-2 showed a similar pattern. On the contrary, 3 and 5 showed different patterns. These results suggest the configuration of Aoe in natural Cyl-2 to be L and the conformation of Cyl-2 to be similar to those of 2 and 4. Based on the results of ^1H- and ^<13>C-n.m.r. studies, differential N-methylation and model buildings, the backbone structure of 2 is proposed to be a unique trans-trans-cis-trans conformation, the L-Ile-L-Pro bond being cis.
天然有機化合物討論会の論文
1979-09-20