Alkaloids of Thalictrum. VIII. Isolation of Thalidasine from Thalictrum rugosum

Alkaloids of Thalictrum. XXXIII. Isolation and Characterization of Alkaloids From the Root of Thalictrum alpinum

“…The nmr spectrum identified one iV-methyl, four O-methyls, and nine aromatic protons, while the ir spectrum showed hydroxyl absorption at 3535 cm-1. The cd curve was similar to that of thalidasine (3). AT-methylation of iY-desmethylthalrugosidine with formaldehyde and sodium borohydride produced thalrugosidine (4), thereby establishing the structure including stereochemistry for this alkaloid, except for the position of the AT-methyl group.…”

“…Methylation of thalpindione (1) with diazomethane gave thalrugosinone (2), proving that the starting material was monophenolic and that its complete structure, as argued for thalrugosinone (2) of the phenolic group, can be given as in 1. The cd spectrum is little changed in going from thalpindione (1) to thalrugosinone (2) and is very similar to that of thalidasine (3), (2,3) and thalrugosidine (4) (4), thus underscoring a similar conformation for these alkaloids. Consequently, the chemical shifts of .V-methyls and O-methyls in the nmr spectra would have relatively fixed positions and could be used for location of substituents.…”

“…49-52 of the ethersoluble nonphenolic tertiary alkaloids was rechromatographed on 30 g of neutral alumina with benzene (200 ml), benzene-chloroform (2:1, 250 ml) and (1:2, 400 ml) as eluents. The last two solvents eluted 485 mg of a homogeneous base that gave identical specific rotation, tic mobility, and uv, ir, nmr and cd spectra as authentic thalidasine (3) (2, 3). Thalrugosidine (4).-.4.…”

Alkaloids of Thalictrum XXX. Eleven Minor Alkaloids From Thalictrum rugosum

“…The last solvent eluted 53 mg of protopine (5) that crystallized from methanol as colorless prisms: mp 203-4°[ lit. (17) mp 207°]; Rf 0.85 on tic with silica gel G and benzene-acetone-ammonium hydroxide solution (20:20:0.6); ir (CHC13) v max 1655 cm""1 (C = 0); nmr (18) (90 MHz, CDC13) 1.91 (s, NMe), 2.52 and 2.84 (2 brm, 2H each, CH2CH2), 3.57 and 3.77 (2s, 2H each, 2 CH2), 5.90 and 5.93 (2s, 2H each, OCH20), 6.66 (s, 2H, o-ArH), 6.63 and 6.89 (2s, 1H each, 2 ArH). Identification was made by comparison of physical properties to those reported in the literature.…”

“…The mass spectrum, however, did exclude the hernandezine-related structure. Comparison of the chemical shifts for the -Y-methyl and -methyl groups of thalrugosinone (2) with those of thalidasine (6) and thalrugosaminine (7) showed only a very small difference from the thalidasine positions (largest difference of 3.6 Hz and average of 1.5 Hz), while with thalrugosaminine, the difference was greater (largest 15 Hz and average 5.3 Hz). Furthermore, the multiplicity pattern of the aromatic protons of thalrugosinone was similar to that of thalidasine, but clearly different from thalrugosaminine.…”