Prolinimines: N-Amino- l -Pro-methyl Ester (Hydrazine) Schiff Bases from a Fish Gastrointestinal Tract-Derived Fungus, Trichoderma sp. CMB-F563

A rice cultivation of a fish gastrointestinal tract-derived fungus, Trichoderma sp. CMB-F563, yielded natural products incorporating a rare hydrazine moiety, embedded within a Schiff base. Structures inclusive of absolute configurations were assigned to prolinimines A–D ( 1 – 4 ) on the basis of detailed spectroscopic and C 3 Marfey’s analysis, as well as biosynthetic considerations, biomimetic total synthesis, and chemical transformations. Of note, monomeric 1 proved to be acid labile and, during isolation, underwent quantitative transformation to dimeric 3 and trimeric 4 . Prolinimines are only the second reported natural products incorporating an N -amino-Pro residue, the first to include l -Pro, the first to occur as Schiff bases, and the first to be isolated from a microorganism.