Unequivocal NMR assignments: O -methoxy-methyl esters derivatives of acid chromanones from Calophyllum brasiliense CAMB. (Guanandi)

The present work describes the fractionation of the crude hexane extract (EBHEX) from Calophyllum brasiliense (Clusiaceae) stem bark. Derivatization of DCM 2-9 fraction with diazomethane afforded the chromanones inophylloidic acid, isobrasiliensic acid, as well as, a mixture containing isobrasiliens...

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Published inNatural product research Vol. 22; no. 10; pp. 846 - 853
Main Authors Caneppele, D., Vieira, P. C., Dall'oglio, E. L., da Silva, L. E., Sousa, P. T.
Format Journal Article
LanguageEnglish
Published England Taylor & Francis Group 10.07.2008
Subjects
Acid chromonones
Calophyllum - chemistry
Calophyllum brasiliense
Chromones - chemistry
Esters
Magnetic Resonance Spectroscopy - methods
Molecular Structure
Plant Bark - chemistry
Plant Extracts - chemistry
Unequivocal NMR assignments
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Summary:The present work describes the fractionation of the crude hexane extract (EBHEX) from Calophyllum brasiliense (Clusiaceae) stem bark. Derivatization of DCM 2-9 fraction with diazomethane afforded the chromanones inophylloidic acid, isobrasiliensic acid, as well as, a mixture containing isobrasiliensic and brasiliensic acids, in the form of their more stable O-methoxy-methyl esters derivatives 1, 2, and 3, respectively. The isolation of 1 from C. brasiliense is described for the first time herein. The use of two-dimensional NMR methods ( 1 H-COSY, HMQC, and HMBC) allowed the precise determination of 13 C and 1 H chemical shifts of compounds 1, 2, and 3.
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ISSN:1478-6419
1478-6427
DOI:10.1080/14786410701582282