The Carbon-13 NMR Spectra of Aporphine Alkaloids

14‐Membered Cyclopeptides from Paliurus ramosissimus and P. hemsleyanus

“…The models for these 14-membered bases, as represented by 6 and 9 in Fig. 2, revealed an endocyclic Hbond between amido C(7)O and HÀN(3) in addition to an exocyclic one between amido C(1')O and HÀN (6). Inspection of these models indicated that their peptide torsion angles (f and f) conform to that of an a-helix.…”

“…To enrich the chemical bank of these cyclopeptides, we also studied the chemical constituents of a related plant, P. hemsleyanus Rehd., a deciduous tree widely distributed in southern China [5]. This work resulted in the isolation of four 14-membered cyclopeptides 7 ± 10, and an aporphine nuciferine [6], in addition to the reported ceanothic acid esters [7]. In the present paper, we report the structure characterization of these compounds.…”

“…and then partitioned with CHCl 3 (3 Â 2 l) to give the free bases (2.17 g) [3]. Part of this fraction (808 mg) was chromatographed (silica gel (230 ± 400 mesh, 40 g), 0 ± 2% i PrOH/cyclohexane): 9 (20.4 mg), 10 (7.1 mg), 7 (40.1 mg), and nuciferine [6] 9), C(19); HÀC(2') 3 C(3'), C(4'), Me 2 N; HÀC(6') 3 C(4'), C(5'), C(8'), C(10'); HÀC(9') 3 C(5'), C(7'); HÀC(12') 3 C(4'), C(5'), C(10'); Me 2 N 3 C(2'). FAB-MS (pos.…”

Oxazine‐ and oxazole‐fused derivatives of the alkaloid boldine and their complete structural and spectral assignments by HMQC and HMBC experiments

“…This, in turn, proves that the precursor of the annellated boldine derivatives is 8-aminoboldine (3), and that therefore electrophilic nitrosation in acetic acid occurred regioselectively at C-8 to afford 2, unlike halogenation with N-halosuccinimides in trifluoroacetic acid, which occurs preferentially at C-3. 3 The complete assignments of the 1 H and 13 C NMR spectra of boldine 10,11 and some of its halogenated derivatives have been published previously. The structures of 8-nitrosoboldine (2), 8-aminoboldine (3), 1,11-dimethoxy-2-hydroxy-6-methyloxazolo[4,5-k]-5,6, 6a,7-tetrahydro-4H-dibenzo[de,g]quinoline (4), 1,12-dimethoxy-2-hydroxy-6-methyl-9-phenyl-10H-oxazin[5,6-k]-5,6,6a, 7-tetrahydro-4H-dibenzo[de,g]quinolin-10-one (5) and 1,11-dimethoxy-2-hydroxy-6-methyl-9-phenyloxazolo[4,5-k]-5,6, 6a,7-tetrahydro-4H-dibenzo[de,g]quinoline (6) are shown in Fig.…”

New Benzenoids from the Roots of Lindera aggregata

“…Previous phytochemical studies on Wu Yao have led to the isolation of sesquiterpenes [6], alkaloids [7,8], flavonoids [9] and lignans [10]. In this study, two new benzenoids, linderagatin-A (1) and linderagatin-B (2), were isolated from L. aggregata, as well as 27 known compounds, N-trans-feruloyltyramine (3) [11], N-cisferuloyltyramine (4) [11], N-trans-feruloylmethoxytyramine (5) [12], thalifoline (6) [13], yuzirine (7) [14], linderaggrine-A (8) [8], northalifoline (9) [15], (+)-boldine (10) [16], (+)-Nmethyllaurotetanine (11) [17], (+)-isoboldine (12) [11], 3-hydroxy-1-(4-hydroxyphenyl)propan-1-one (13) [18] , p-hydroxybenzoic acid (14) [12], 4-hydroxy-3-methoxy acetophenone (15) [19], methyl 3,5-dimethoxy-4-hydroxy-benzoate (16) [20], vanillic acid (17) [12], tyrosol (18) [21], 2-(4-hydroxy-3-methoxyphenyl)ethanol (19) [22], 2-(4-hydroxy-3,5-dimethoxyphenol)ethanol (20) [23], 3hydroxy-1-(4-hydroxyphenyl)propan-1-one (21) [18], rel-(2α, 3β)-7-O-methylcedrusin (22) [24], (-)-lyoniresinol (23) [25], hydroxylindestrenolide (24) [6], 2,6-dimethoxy-p-quinone (25) [26], evofolin-B(26) [27], (-)-boscialin (27) [28], methyl dihydrophaseate (28) [29], and 6′-O-vanilloyltachioside (29) [30]. Here, we report the structure elucidation of the two new benzenoids.…”