Abstract
Four modified cyclic hexapeptides, tenuecyclamides A-D (1-4), were isolated along with the known antibiotic, borophycin (5), from the methanol extract of Nostoc spongiaeforme var. tenue (TAU strain IL-184-6). The planar structure of tenuecyclamides A-D (1-4) was determined by homonuclear and inverse-heteronuclear 2D-NMR techniques as well as by high-resolution mass spectrometry measurements. The absolute configuration of the asymmetric centers was studied by Marfey's method for HPLC. The stereochemistry of the asymmetric centers in tenuecyclamides A and B (1 and 2) could not be fully determined, while that of tenuecyclamides C and D (3 and 4) was unambiguously determined.
Original language | English |
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Pages (from-to) | 1248-1251 |
Number of pages | 4 |
Journal | Journal of Natural Products |
Volume | 61 |
Issue number | 10 |
DOIs | |
State | Published - Oct 1998 |