HREIMHalverton Real Estate Investment Management Ltd. (London, UK)
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The molecular formula C31H62O was determined by HREIMS, which produced the molecular ion peak [M+] at m/z 450.0165 (calcd.
239-241[degrees]C; IR (KBr) v/[cm.sup.-1]: 3427, 3362, 3219, 3162, 2914, 2888, 1605, 1515, 1433, 1282, 1254; [sup.1]H NMR (CD[Cl.sub.3], 300 MHz) [delta]: 0.60 (3H, s, 18-C[H.sub.3]), 0.65 (3H, d, J = 6.6, 21-C[H.sub.3]), 1.21 (3H, s, 19-C[H.sub.3]), 3.56-3.45 (1H, m, [C.sub.3]-H), 5.37 (1H, brs, C6-H), 6.238 (1H, s, -N[H.sub.2]), 7.22 (1H, s, -N[H.sub.2]), 8.51 (1H, s, -NH-); [sup.13]C NMR (CD[Cl.sub.3], 75 MHz) [delta]: 179.0 (-C=S), 153.2 (-C=N), 140.8 (5-C), 121.4 (6-C), 71.1 (3-C), 59.0 (14-C), 56.5 (17-C), 56.4 (9-C), 50.1 (13-C), 42.9 (4-C), 48.8 (12-C), 42.2 (8-C), 37.2 (1-C), 36.5 (10-C), 31.8 (7-C), 31.6 (16-C, 2-C), 24.1 (15-C), 21.0 (11-C), 19.4 (21-C), 17.3 (19-C), 13.2 (18-C); HREIMS: m/z 390.2577 [[M+H].sup.+] (calcd for [C.sub.22][H.sub.36][N.sub.3]OS, 390.2579).
Broussochalcone B (2): yellowish powder; mp 168-169 [degrees]C; EIMS, m/z 324 [[M].sup.+]; HREIMS, m/z 324.1363 (calculated for [C.sub.20][H.sub.20][O.sub.4], 324.1362); [sup.1]H and [sup.13]C NMR data were consistent with previously published data (Ryu et al., 2010).
Compound 1 showed a molecular ion at m/z 418.1270 in its HREIMS and the presence of 21 carbons on the [sup.13]C NMR spectrum suggested a molecular formula [C.sub.21][H.sub.22][O.sub.9].
The HREIMS mass spectrum revealed a [[M + H].sup.+] ion at m/z 590.5124 corresponding to the molecular formula [C.sub.28][H.sub.30][O.sub.14].
The molecular formula was established as, C19H34N2, by HREIMS (m/z 290.2704), requires four degrees of unsaturation.
The HREIMS was recorded on a JEOL-Accu-TOF JMS-T100LC mass spectrometer having a DART source (direct analysis in real time) Column chromatography was carried out using silica gel (Merck, 60-120 mesh).
Their structures were elucidated as 3[beta]-12-ursen-3yl-docosanoate (1) and 3[beta]-12-ursen-3yl-nonacosanoate (2) by 1D-NMR (1H and 13C), 2D-NMR (HMQC, 1H-1H COSY, HMBC and NOESY), EIMS, HREIMS and chemical analyses.
246-248 AdegC; [[alpha]]D20 +55.5 (c = 1.08, CHCl3); IR (KBr) max cm-1 2950, 1755, 1695, 1650, 895; HREIMS, [M+] at m/z 452.3265 (calcd.
The structure of marchantin A (1) was confirmed by NMR and HREIMS. Marchantin A inhibited proliferation of the Plasmodium falciparum strains, NF54 ([IC.sub.50] = 3.41 [micro]M) and K1 ([IC.sub.50] = 2.02 [micro]M) and showed activity against other protozoan species Trypanosoma brucei rhodesiense, T.
The structures were elucidated by the extensive use of sophisticated spectroscopic techniques (1HNMR, 13C-NMR, HMQC, HMBC, 1H-1H COSY, NOESY, EIMS, HREIMS, and IR).