NMR Spectra of Sparteine N1-oxide and α-Isosparteine N-oxide

Abstract

Sparteine N1-oxide and α-isosparteine N-oxide were prepared and their structures determined for the first time by 1H- and 13C-NMR spectroscopy using two-dimensional techniques. The N-oxide effects were also calculated.

The observed and calculated 1H and 13C chemical shifts of tertiary amines and their N‐oxides

“…In the literature, there are several examples of the combination of experimental NMR data with calculated NMR parameters (shielding nuclear constants and scalar couplings) addressing various stereochemical problems, e.g. the conformation of sparteine N ‐oxides,14, 15 the conformation and configuration of tertiary amines via GIAO‐derived 13 C chemical shifts and a multiple independent variable regression analysis,16 the conformation of N ‐substituted piperidines and pyrrolidines17 or the relevance of the calculated 1 H, 13 C and 15 N shieldings in amines in conformational analysis 18. GIAO NMR calculations combined with probability analysis were also used for the assignment of stereochemistry when the NMR data were available only for one diastereoisomer 19…”

Quinolizidine Alkaloids with Antitomato Spotted Wilt Virus and Insecticidal Activities from the Seeds of Thermopsis lanceolata R. Br

“…Thermseedline M (13) had a molecular formula of C 15 H 20 N 2 O 4 as determined by its HRESIMS (m/z: 261.1590 [M + H] + ; calcd for 261.1598). The NMR data showed that 13 was a hydroxyl analog of thermopsine (25). The 1 H-1 H COSY correlations of H 2 -13/H-14/H 2 -15 demonstrated that the hydroxyl group was connected to C-14 (δ C 64.4) (Figure 2).…”

“…The NMR spectroscopic data of 11 showed signals for five methylenes, eight methines, and three quaternary carbons. The aforementioned data suggested that 11 was a homolog of thermopsine (25). 20 The downfield shifts of C-12 (δ C 54.9, 4).…”

“…In addition, known analogues were identified as N-(β-D-glucopyranosyl) cytisine ( 17), 12 cytisine (18), 13 N-methylcytisine (19), 14 (−)-12-hydroxycytisine (20), 15 N-formylcytisine (21), 16 N-acylcytisine (22), 17 methyl ester of N-cytisinylacetic acid (23), 18 cytisine-12carbamide (24), 19 thermopsine (25), 20 13β-hydroxythermopsine (26), 21 anagyrine ( 27), 21 epibaptifoline (28), 22 baptifoline (29), 22 (+)-5,6-dehydrolupanine (30), 23 (−)lupanine (31), 24 and sparteine N1-oxide (32). 25 Structure Elucidation of New Compounds. Thermseedline A ( 1 The absolute configuration of 1 was established as (7R, 9R) by the biosynthetic pathway and NMR data analyses.…”

“…Thermseedline L (12) had a molecular formula of C 15 H 18 N 2 O 2 ([M + H] + m/z 259.1437). The NMR spectroscopic data suggested that 12 was the oxidation product of thermopsine (25), and the key HMBC correlations from H-7, H-11, and H 2 -15 to C-17 (δ C 167.4) demonstrated that 12 was 17-oxothermopsine (Figure 2).…”