Δ5-Dehydroskytanthin und 8-skytanthin in Tecoma stans

ChemInform Abstract: Three New Monoterpene Alkaloids and a New Caffeic Acid Ester from Incarvillea mairei var. multifoliolata

“…suggested that a OH group was attached to C (7). This inference was confirmed by the HMBCs MeN/C(1) and C(3), and HÀC(7)/C(5), C(6), and C (11). The suggested constitution of 3 (5,6-didehydro-7-hydroxyskytanthine Noxide) was confirmed by extensive 2D-NMR experiments, including DQF-COSY, HSQC, and HMBC (Fig.…”

“…The molecular formula was determined as C 11 H 19 NO 2 from the positive-ion-mode HR-ESI-MS (m/z 198.1496 ([M þ H] þ )). Comparison of the 1 H-and 13 C-NMR data of 3 ( Table 1) with those of 5,6didehydroskytanthine [11] suggested that 3 has a similar molecular skeleton as the latter. suggested that a OH group was attached to C (7).…”

“…The relative configuration of 1 was determined by NOESY correlations. The NOESY correlations HÀC(5)/HÀC(4), HÀC(9), and Me (11), and HÀC(9)/Me(11) indicated that HÀC(5), HÀC(9), and Me(11) are b-oriented, while Me(10) is on the opposite face of the molecule (Fig. 3).…”

“…2). The relative configuration of 2 was determined by the NOESY correlations HÀC(5)/HÀC(4), HÀC(5)/HÀC(9), HÀC(5)/CH 2 (11), and HÀC(9)/ CH 2 (11) ( Fig. 3).…”

(-)-δ-N-Normethylskytanthine from Tecoma arequipensis

“…In summary, work in the early 1960s showed the major alkaloid of Skytanthus acutus to be( + )-3-skytanthine [2], with smaller amounts of (+ --skytanthine [31 and (+)-8-skytanthine [4] also being present. Later a (+)-N-normethylskytanthine (7) and (+ )-8-skytanthine (8) were reported from T. stans, along with a variety of other alkaloids. The N-normethylskytanthine was methylated (7) to a skytanthine whose optical rotation and picrate melting point were in close agreement with those for -skytanthine.…”