TY - JOUR
T1 - Absolute configuration of tropane alkaloids from Schizanthus species by vibrational circular dichroism
AU - Reina, Matías
AU - Burgueño-Tapia, Eleuterio
AU - Bucio, María A.
AU - Joseph-Nathan, Pedro
N1 - Funding Information:
This work was partially supported by the Ministerio de Educación y Ciencia, Spain (CTQ2006-15597-C02-01PPQ), SIP-IPN-Mexico, CONACYT-Mexico and CYTED.
PY - 2010/5
Y1 - 2010/5
N2 - The absolute configuration (AC) of 6β-hydroxy-3α-senecioyloxytropane (1), 3α-hydroxy-6β-tigloyloxytropane (2), 3α-hydroxy-6β-senecioyloxytropane (3), and 3α-hydroxy-6β-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 1H 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 3α,6β-tropanediol derivatives.
AB - The absolute configuration (AC) of 6β-hydroxy-3α-senecioyloxytropane (1), 3α-hydroxy-6β-tigloyloxytropane (2), 3α-hydroxy-6β-senecioyloxytropane (3), and 3α-hydroxy-6β-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 1H 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 3α,6β-tropanediol derivatives.
KW - 3α,6β-Tropanediol alkaloids
KW - Absolute configuration
KW - S. pinnatus
KW - Schizanthus grahamii
KW - Schizanthus species
KW - Solanaceae
KW - Vibrational circular dichroism
UR - http://www.scopus.com/inward/record.url?scp=77950367825&partnerID=8YFLogxK
U2 - 10.1016/j.phytochem.2010.02.004
DO - 10.1016/j.phytochem.2010.02.004
M3 - Artículo
SN - 0031-9422
VL - 71
SP - 810
EP - 815
JO - Phytochemistry
JF - Phytochemistry
IS - 7
ER -