Table 1 Key correlations from 2 D in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Table 1 Key correlations from 2D NMR experiments in the structure elucidation of undescribed alkaloid 9 (HMBC interaction – blue arrow; H2BC and COSY interaction – red bond) and its 1 H and 13 C NMR chemical shifts assigned to the related position in ppm with coupling constants (in parenthesis, reported in Hz).. Positionvincaminorudeine 9500 MHz, CDCl3125 MHz, CDCl32139.134.39, dd (4.1, 2.7)38.742.63–2.55, m31.11.92, dd (14.3, 4.1)542.961.36–1.21, m31.71.06, td (12.5, 5.5)71.52–1.39, m22.31.36–1.21, m82.38–2.22, m55.2102.63–2.55, m53.62.38–2.22, m113.05–2.85, m22.312110.313127.0147.53, dd (7.8, 1.1)118.1157.09, dd (7.8, 1.1)118.5167.19, dd (7.8, 1.1)120.7177.27, dd (7.8, 1.1)108.618136.7193.75–3.70, m, overlap56.61.64, d (12.5)203.47, q (6.5)74.2211.29, d, overlap (6.5)17.6C= O177.03-COOCH33.72, s, overlap52.7N CH33.54, s30.3