Unequivocal NMR assignments: O -methoxymethyl esters derivatives of acid chromanones from Calophyllum brasiliense CAMB. (Guanandi)
Unequivocal NMR assignments: O -methoxymethyl esters derivatives of acid chromanones from Calophyllum brasiliense CAMB. (Guanandi)
- Natural Products Research, 22(10), 846-853, 2008 .
Artículo
The present work describes the fractionation of the crude hexane extract (EBHEX) from Calophyllum brasiliense (Clusiaceae) stem bark. Derivatization of DCM2-9 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 13C and 1 H chemical shifts of compounds 1, 2, and 3.
CALOPHYLLUM BRASILIENSE
ACID CHROMONONES
UNEQUIVOCAL NMR ASSIGNMENTS
Artículo
The present work describes the fractionation of the crude hexane extract (EBHEX) from Calophyllum brasiliense (Clusiaceae) stem bark. Derivatization of DCM2-9 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 13C and 1 H chemical shifts of compounds 1, 2, and 3.
CALOPHYLLUM BRASILIENSE
ACID CHROMONONES
UNEQUIVOCAL NMR ASSIGNMENTS