title: Chiral resolution and absolute configuration of 3alpha,6beta-dicinnamoyloxytropane and 3alpha,6beta-di(1-ethyl-1H-pyrrol-2-ylcarbonyloxy)tropane, constituents of Erythroxylum species.
abstract: Chiral resolution of (+/-)-3alpha,6beta-dicinnamoyloxytropane (1) and (+/-)-3alpha,6beta-di(1-methyl-1H-pyrrol-2-ylcarbonyloxy)tropane (2), prepared by esterification of (+/-)-3alpha,6beta-tropanediol (3), was achieved using an amylose-derived HPLC stationary phase and normal phase conditions. The corresponding vibrational circular dichroism (VCD) spectra provided the absolute configuration of the enantiomers as (-)-(3R,6R)-1, (+)-(3S,6S)-1, (-)-(3R,6R)-2 and (+)-(3S,6S)-2. In each case, characteristic VCD bands for the absolute configuration determination of the 3alpha,6beta-tropandiol esters were observed. While the absolute configuration of natural 1, previously isolated from Erythroxylum hypericifolium, could not be established due to the lack of literature optical rotation values, that of catuabine E, previously isolated from E. vacciniifolium, is now assigned as (-)-(3R,6R)-2 by comparison with the optical rotation values of the prepared samples and the reported rotation of the natural product.
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Muñoz
authors.forename: Solange
authors.initials: S
authors.lastname: Arriagada
authors.forename: Pedro
authors.initials: P
authors.lastname: Joseph-Nathan
mesh_terms: D002934:Cinnamates / Q000737:chemistry*; D002942:Circular Dichroism; D030921:Erythroxylaceae / Q000737:chemistry*; D008968:Molecular Conformation; D014326:Tropanes / Q000737:chemistry*
chemical_list: C587759:3alpha,6beta-di(1-ethyl-1H-pyrrol-2-ylcarbonyloxy)tropane; C587758:3alpha,6beta-dicinnamoyloxytropane; D002934:Cinnamates; D014326:Tropanes