Showing papers on "Lyngbya majuscula published in 1995"
136 citations
TL;DR: The absolute stereochemistry of the cyclohexenone moiety of malyngamide H was deduced by a combination of 2D NOESY and exciton chirality circular dichroism spectroscopy.
Abstract: Guided by ichthyotoxic activity against goldfish, a new lipopeptide, malyngamide H [1], and its corresponding free acid, 7-methoxytetradec-4(E)-enoic acid [2], have been isolated from the tropical marine cyanobacterium Lyngbya majuscula. The structure of the new carbon skeleton borne by malyngamide H was elucidated on the basis of spectroscopic analysis, mainly 2D nmr. The absolute stereochemistry of the cyclohexenone moiety of malyngamide H [1] was deduced by a combination of 2D NOESY and exciton chirality circular dichroism spectroscopy.
64 citations
64 citations
TL;DR: The complete relative and absolute configuration of curacin A is defined by comparison of products obtained from chemical degradation of the natural product with the same substances prepared by synthesis.
52 citations
TL;DR: An ichthyotoxic amide of 7(S )-methoxytetradec-4(E )-enoic acid was isolated from an Okinawan collection of Lyngbya majuscula as mentioned in this paper.
45 citations
TL;DR: Two new and potent antimitotic metabolites were isolated from a Curacao collection of Lyngbya majuscula and the absolute stereochemical configuration of 2 was deduced to be 2R,13R,19R,21S by its thermally induced interconversion with 1.
Abstract: Two new and potent antimitotic metabolites, curacins B [2] and C [3], were isolated from a Curacao collection of Lyngbya majuscula. The structures of 2 and 3, geometrical isomers of the known compound curacin A [1], were determined by detailed spectroscopic analysis in comparison with 1. The absolute stereochemical configuration of 2 was deduced to be 2R,13R,19R,21S by its thermally induced interconversion with 1.
44 citations
16 citations
TL;DR: In this article, the metabolite of the marine cyanophyte Lyngbya majuscula (4E,7S)-(−)-7-methoxy-4-tetradecenoic acid (1) has been synthesized for the first time in optically active form in eight steps in 20% overall yield, Heptyloxirane (3) and the alkyne 4 containing the carboxyl group masked as a tricyclic orthoester were prepared by known methods from 5 and 6 as starting materials.
Abstract: The metabolite of the marine cyanophyte Lyngbya majuscula (4E,7S)-(−)-7-methoxy-4-tetradecenoic acid (1) has been synthesized for the first time in optically active form in eight steps in 20% overall yield, Heptyloxirane (3) and the alkyne 4 containing the carboxyl group masked as a tricyclic orthoester were prepared by known methods from 5 and 6 as starting materials. Reaction of lithiated 4 with 3 afforded in 74% yield the alkyne 2 which could easily be transformed into the target molecule. Hydrogenation with Lindlar catalyst produced 7 which could be isomerized to 8 with (E) configuration. Methylation of the 7-hydroxy group in 8 gave 9 which could be transformed into the methyl ester 10 and the (4E,7S)-acid 1 in high yield.
16 citations
TL;DR: In this article, the relative and absolute configuration of Curacin A is defined by comparison of products obtained from chemical degradation of the natural product with the same substances prepared by synthesis.
Abstract: Curacin A is a structurally novel antimitotic agent isolated from the Caribbean cyanobacterium Lyngbya majuscula. Its planar structure has been previously determined from a spectroscopic investigation. Here, we define the complete relative and absolute configuration of curacin A by comparison of products obtained from chemical degradation of the natural product with the same substances prepared by synthesis. Curacin A is shown to have 2R, 13R, 19R, 21S absolute configuration.
6 citations
2 citations
TL;DR: In this paper, a new lipopeptide, malyngamide H, and its corresponding free acid, 7-methoxytetradec-4(E)-enoic acid, have been isolated from the tropical marine cyanobacterium Lyngbya majuscula.
Abstract: Guided by ichthyotoxic activity against goldfish, a new lipopeptide, malyngamide H [1], and its corresponding free acid, 7-methoxytetradec-4(E)-enoic acid [2], have been isolated from the tropical marine cyanobacterium Lyngbya majuscula. The structure of the new carbon skeleton borne by malyngamide H was elucidated on the basis of spectroscopic analysis, mainly 2D nmr. The absolute stereochemistry of the cyclohexenone moiety of malyngamide H [1] was deduced by a combination of 2D NOESY and exciton chirality circular dichroism spectroscopy.