Absolute configuration of tropane alkaloids from Schizanthus species by vibrational circular dichroism

作者：Reina Matias; Burgueno Tapia Eleuterio; Bucio Maria A; Joseph Nathan Pedro^*

来源：Phytochemistry, 2010, 71(7): 810-815.

DOI：10.1016/j.phytochem.2010.02.004

• Schizanthus grahamii
• S. pinnatus
• Solanaceae
• Absolute configuration
• Vibrational circular dichroism
• 3 alpha,6 beta-Tropanediol alkaloids
• Schizanthus species

The absolute configuration (AC) of 6 beta-hydroxy-3 alpha-senecioyloxytropane (1), 3 alpha-hydroxy-6 beta-tigloyloxytropane (2), 3 alpha-hydroxy-6 beta-senecioyloxytropane (3), and 3 alpha-hydroxy-6 beta-angeloyloxytropane (4) was assigned as (1R,3R,5S,6R) using density functional theory (DFT) calculations at the B3LYP/DGDZVP level of theory in combination with experimental vibrational circular dichroism (VCD) measurements and comparison with the spectra of similar tropanes. The AC of 1 followed from a sample isolated from Schizanthus grahamii, while those of the mixture of 2 and 3, isolated from the same source, were determined by comparing the VCD measurement to a weighted calculation of the individual VCD spectra according to a 69:31 ratio of 2:3 determined by (1)H NMR signal integration. In turn, Schizanthus pinnatus provided a 7:3 mixture of 1:4 whose AC was determined using the experimental VCD absorptions in the 1150-950 cm(-1) spectral region which were compared with those observed for 1-3 and with those described for other 3 alpha,6 beta-tropanediol derivatives.

• 出版日期2010-5