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Complete stereochemistry of neamphamide A and absolute configuration of the beta-methoxytyrosine residue in papuamide B.

ABSTRACT: The absolute stereochemistry of the three unresolved structural components in neamphamide A (1) was determined to be (R)-beta-methoxy-L-tyrosine, (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid, and (2R,3R,4R)-3-hydroxy-2,4,6-trimethylheptanoic acid. Stereochemical assignments were made by chemical degradation of 1, derivatization of the resulting products, and then spectroscopic and chromatographic comparison of the derivatives with synthetically prepared standards. Using the same analytical protocol developed for 1, the beta-methoxytyrosine residue in papuamide B (2) was found to be (R)-beta-methoxy-D-tyrosine. This represents a rare example of divergent stereochemistry in an unusual amino acid residue that is present in two closely related classes of peptides.

SUBMITTER: Oku N

PROVIDER: S-EPMC1513540 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature

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Complete stereochemistry of neamphamide A and absolute configuration of the beta-methoxytyrosine residue in papuamide B.

Oku Naoya N Krishnamoorthy Ravi R Benson Alan G AG Ferguson Robert L RL Lipton Mark A MA Phillips Lawrence R LR Gustafson Kirk R KR McMahon James B JB

The Journal of organic chemistry 20050801 17

The absolute stereochemistry of the three unresolved structural components in neamphamide A (1) was determined to be (R)-beta-methoxy-L-tyrosine, (2R,3R,4S)-4-amino-7-guanidino-2,3-dihydroxyheptanoic acid, and (2R,3R,4R)-3-hydroxy-2,4,6-trimethylheptanoic acid. Stereochemical assignments were made by chemical degradation of 1, derivatization of the resulting products, and then spectroscopic and chromatographic comparison of the derivatives with synthetically prepared standards. Using the same an ...[more]

PMID: 16095304

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