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

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• 作者：Matí ; as Reina ; Eleuterio Burgueñ ; o-Tapia ; Marí ; a A. Bucio ; Pedro Joseph-Nathan
• 关键词：Schizanthus grahamii ; S. pinnatus ; Solanaceae ; Absolute configuration ; Vibrational circular dichroism ; 3α ; ; 6β ; -Tropanediol alkaloids ; Schizanthus species
• 刊名：Phytochemistry
• 出版年：2010
• 出版时间：May 2010
• 年：2010
• 卷：71
• 期：7
• 页码：810-815
• 全文大小：526 K

文摘

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.