Electron‐impact mass spectrometry of Nuphar alkaloids

Abstract

Principal peaks in the mass spectra of deoxynupharidine are accounted for on the basis of high resolution mass spectrometry and peak shifts in the mass spectra of deoxynupharidine-4-d1 and deoxynupharidine-6/3,7,9-d2. Cleavage of the quinolizidit~e ring system of deoxynupharidine occurs predominantly in ring A, giving m/e 136, 107, 98, 94 and 81. The origins of the family of ions [Malkyl]+ and m/e 178 are considered. A comparative survey is made of the occurrence of these ions, and others, in the mass spectra of piperidine, quinolizidine and thiospirane types of Nuphar alkaloids. Attention is directed to ions useful in distinguishing structural types.MASS spectral data have been given for several Nuphar alkaloids in the reports of the structure elucidation of these compounds. However, not all of these reports have given evidence for the origin of the peaks, nor has there been a broad comparison of the spectra of various structural types of Nuphar alkaloids. We present here a comparison of the mass spectra we have obtained for several Nuphar alkaloids and indicate peaks that are useful in distinguishing the various structural types. We also call attention to the origin of principal peaks for those cases where the mass spectra of deuterium labeled compounds* and high resolution spectra are available.Fundamentally Nuphar alkaloids are of two structural types; those containing, respectively, piperidine (I to 111) and quinolizidine ring systems. The latter can be further subdivided into two groups; those having a simple quinolizidine ring system (IV to XVI) and those having two such systems (XVII to XXII). (-)-Deoxynupharidine (DON) (IV) is the parent C,,-quinolizidine type alkaloid whose carbonnitrogen skeleton is found in naturally occurring C,, functional group variations of DON (VII, VIII and X), and incorporated into the C,,-thiospiranes (XVII, XX and XXI) and the 6,7/3-oxidodeoxynupharidine dimer (XXII). Since the structure of DON is central to the class of quinolizidine alkaloids, we shall first discuss its mass spectral characteristics in view of labeling and high resolution data. Thereafter we will indicate the fate of each of the principal ions in the mass spectra of the more complex CI5 and C,,-alkaloids~ as well as pointing out the new peaks which appear.* The preparation of each of the deuterium labeled compounds is reported in the reference cited for that compound. t The mass spectral data for several epimeric alkaloids have been determined but since the low resolution mass spectra of epimers are very similar, we will only give the data for one of the epimers. An exception is the thiospirane alkaloids. Epimeric pairs whose mass spectra have been determined are: deoxynupharidine and 7-epideoxynupharidine, nupharolutine and 7-epinupharolutine, nuphamine and 3-epinuphamine, deoxynupharidin-6, 7a-diol and deoxynupharidin-6,7@-diol, 7@-methylthiodeoxynupharidin-6a-01 and 7a-methylthiodeoxynupharidin-6P-ol, 7,!7-methylthiodeoxynupharidine and 7cc-rnethylthiodeoxynupharidine, 6,7[j-oxidodeoxynupharidine dimer a...

Indolizidines, .alpha.-arylthiohemiaminals, and .alpha.-arylsulfonylhemiaminals from a quinolizidine enamine and an arenesulfonyl chloride

“…29 The frozen contents were warmed to 25 °C, and the persisting solid filtered and washed with 0 2012-08 8, yielding'53 mg of p-tolyl disulfone (2): mp 204 °C dec (lit. 212 °C dec2); ir 6.05 (w), 6.27 (m), 7.48 (s), 7.71 (m), 8.82 (s), 9.41 (m), 12.43 (m), 14.46 µ (m); MS (110 °C) m/e (rel intensity) 310 (7) (M+), 262 (9), 155 (73), 139 (100), 92 (53).…”

“…Fractions D16-D27 (13 mg) were combined with fractions C26-C36 (14 mg) and chromatographed on 10 g of Si02 (activity 2) with 455 ml of CH2C12 in 13 35-ml fractions and then with 10% MeOH in CH2C12 in a single fraction which yielded 15 mg of material which was applied to a 20 X 20 cm plate coated with 0.25 mm of Si02. This was developed twice with 3:2 CaHa-Et20 and the Rf 0.44 band was removed to obtain 12 mg of 7 (0.0298 mmol, 0.64%), an oil: NMR 0.88 (m, 6 H with 0.90 s, C-l CH3), 0.90 (s superposed on 0.88 m, 6 H with 0.88 m, C-7 CH3), 2.45 (s, 3 H, Ar CH3), 3.53-3.95 (m, 2 , 1 H on addition of D20, C-4 H and C-6 OH), 5.03 (br s becoming narrow on addition of D20,1 H, C-6 H), 6.74 (m, 1H, 3-furyl ß H), 7.2-7.8 (m, 6 H, 3 furyl a H and Ar H); ir (CCI4) 2.85 (w), 5.79 (w), 6.00 (w), 6.24 (m), 6.68 (m), 6.87 (s), 6.27 (m), 7.64 (s), 7.71 (s), 8.66 (s), 8.77 (s), 8.93 (s), 11.48 µ (s); MS (130 °C) m/e (rel intensity) 403 (4), 385 (12), 374 (0.4), 370 (0.6), 357 (5), 321 (6), 248 (6), 229 (100), 228 (41), 214 (40), 200 (21), 107 (36.3), 94 (53), 91 (34), 81 (25); CD (c 0.46 mg/ml, neutral 95% EtOH, l = 0.1 dm -14 600°; CD (c 0.13 mg/ml, 95% EtOH, HCIO4 added, l = 0.1 dm) [0]238 -6 1 300°; high-resolution mass spectrum (70 eV, 110 °C) obsd/calcd mass (formula) 385.1709/ 385.1712 and 385.1740/385.1712 (C22H27N03, [M -H20]+).…”

“…This mixture was rechromatographed (C' series, 10 g of A1203, activity 2) using first benzene and collecting four 20-ml fractions (C'l-C'4) and six 35-ml fractions (C'5-C'10). Fractions C'4-C'8 contained a total of 90 mg of the pure title compound, 4 (0.242 mmol, 8.2%), an oil: TLC (CaHa) Rf 0.25; NMR 0.92 (d, J = 5 Hz, 3 H, C-l CH3), 1.14 (s, C-7 CH3), 2.33 (s, 3 H, ArCH3), 3.12 (br s, 1 H, C-6 OH), 3.75 (d of d, «7 = 4 and 8 Hz, 1 H, C-4 H), 4.03 (br s, 1 H, C-6 H), 6.29 (m, 1 H, 3-furyl ß H), 6.93-7.53 (m, 6 H, 3-furyl a H and ArH); ir (liquid film) 2.86 (m), 6.23 (w), 6.72 (m), 6.94 (m), 7.20 (m), 7.34 (m), 11.48 (s), 12.34 (m), 12.72 µ (m); uv (neutral 95% EtOH) Xmax 264 nm (e 452); uv (95% EtOH, HC104 added) Xmaxi 283 nm (e 3270), Xmax2 274 nm (3350), Xmax3 242 nm (5900); CD (c 0.43 mg/ml, neutral 95% EtOH, 1 = 0. Conversion of 7d-(p-Tolylthio)deoxynupharidin-6-ol (4) to Its Immonium Perchlorate.…”

“…Thereafter the MeOH was vacuum evaporated, the residue mixed with CaHa, the solids removed by filtration, and the filtrate concentrated and added to a column of 15 g of A1203 (activity 2) which was eluted successively with 100 ml of CaHa, 50 ml of 9:1 C8H8-Et20, and 50 ml of 3:2 C8H8-Et20 in 20-ml fractions. Fraction 1 yielded 26 mg of 10: mp 88-89 °C; TLC (8:2 C8H8-Et20) Rf 0.9; NMR 0.84 (br s, 3 H, C-l CH3), 1.22 (s, 3 H, C-7 CH3), 1.77 (d, J = 11 Hz, C-6 ax H), 2.29 (s, 3 H, ArCH3), 2.75 (d, J = 11 Hz, 2 H with 2.88 d of d, C-6 eq H), 2.88 (d of d, J = 4 and 8 Hz, 2 H with 2.75, C-4 H), 6.17 (m, 1 H, 3-furyl ß H), 6.78-7.37 (m, 6 H, 3-furyl a H and ArH); ir (liquid film) 3.66 (m), 6.26 (w), 6.68 (m), 6.72 (m), 7.24 (m), 7.28 (m), 11.42 µ (s); MS m/e (rel intensity) 355 (17) (M+), 267 (12), 232 (92), 231 (43), 220 (16), 178 (20), 136 (34), 107 (23), 96 (49), 94 (100), 84 (56), 81 (22).…”

Mass spectrometry of sulfur‐containing compounds in organic and bioorganic fields

“…They are derivatives of the known Nuphar alkaloids thiobinupharidine 30, thionuphlutine B 31, and neothiobinupharidine 32, Fu represents a furane substituent. The mass spectrometry of these C,,-derivatives has been studied in detail (169)(170), and ions at ml'z 178 and 230 have shown to be characteristic and related to the fragmentation of the tetrahydrothiophene and quinolizidine rings, Scheme 31. On the other hand, the mass spectra of hemiaminals (160, [171][172] are characterized by the presence of mlz 176 and 228 ions.…”