Conformational analysis of the dibenzo [<i>a</i>,<i>g</i>]‐quinolizidines by spectroscopic means. II—The use of high resolution 270 MHz proton magnetic resonance

Tourwé, Dirk; Binst, G. Van; Kametani, T.

doi:10.1002/mrc.1270090612

Cited by 21 publications

(10 citation statements)

References 14 publications

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“…For paper XXII, see Likhitwitayawuid et al (1). [1} (7,8), (-)-asimilobine-2-0^-D-glucoside [2}, (-)-anonaine [3} ( 9), (-)-isolaureline [4} (10), (-)-xylopine [5} (10), (-)-roemeroline [6} (11), (-)-dicentrine [7} (12)(13)(14), ( -)-nordicentrine [8}, ( -)-phanostenine [9} (15), cassythicine [10} (14,16), and magnoflorine [11} (17)(18)(19)(20); (b) the tetrahydroprotoberberines (-)-tetrahydropalmatine {12} (21-23), (-)-capaurine [13} (24-27), ( -)-thaicanine [14} (23), (-)-corydalmine [15} (25,26), ( -)-N-methyltetrahydropalmatine [16} (28), (-)-xylopinine [17} (22), and (-)-tetrahydrostephabine [18} (29); (c) the tetrahydrobenzylisoquinolines (+)reticuline [19} (30,31), (+)-codamine [20} (32,33), and (±)-oblongine [21} (34,35); (d) the hasubanan ( -)-delavaine [22} (36) and the morphinan (-)-salutaridine [23} (37,38). Compounds 2 and 8 are hitherto unknown alkaloids.…”

Section: Resultsmentioning

confidence: 99%

“…Fractions 19 to 2 2 were pooled, dried in vacuo, and recrystallized from Me2CO to give (-)-tetrahydropalmatine [12] (8.4 g). Fraction 24 was further purified by preparative tic eluting with toluene-diethylamine (DEA) (96:4) to afford (-)-xylopinine [22] (15 mg). Fractions 25 to 31 were combined and subjected to preparative tic, using cyclohexane-EtOAc-DEA (5:4:1) as the solvent.…”

Section: Resultsmentioning

confidence: 99%

“…Fractions 25 to 31 were combined and subjected to preparative tic, using cyclohexane-EtOAc-DEA (5:4:1) as the solvent. The lower band, after usual workup, afforded (-)delavaine [22] (25 mg). The upper band was removed and further separated by preparative tic eluting with cyclohexane-EtOAc-DEA (7:2:1) to give (-)-capaurine [13] (9 mg) and (-)-thaicanine [14] (12 mg).…”

Section: Resultsmentioning

confidence: 99%

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Cytotoxic and Antimalarial Alkaloids from the Tubers of Stephania pierrei

Likhitwitayawuid

Angerhofer²,

Chai³

et al. 1993

J. Nat. Prod.

107

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Biological evaluation of extracts prepared from the tubers of Stephania pierrei revealed cytotoxic and antimalarial activity. During the course of separation, two new aporphine alkaloids, (-)-asimilobine-2-O-beta-D-glucoside [2] and (-)-nordicentrine [8], in addition to twenty-one known isoquinoline alkaloids, were isolated. Each isolate was assessed for cytotoxic and antimalarial activities. It was found that the cytotoxicity of S. pierrei was mainly due to the presence of the aporphine alkaloids containing the 1,2-methylenedioxy group 3-10, whereas the antimalarial activity was attributed to the nonquaternary aporphine alkaloids 1, 3-10 and the tetrahydroprotoberberines possessing a phenolic functionality, 13-15, 18. None of the isolates showed a degree of selectivity comparable to that of antimalarial drugs such as chloroquine, quinine, mefloquine, and artemisinin. Comparison of the alkaloid content of S. pierrei and Stephania erecta strongly suggested separate identities for the two plants.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Cytotoxic and Antimalarial Alkaloids from the Tubers of Stephania pierrei

Likhitwitayawuid

Angerhofer²,

Chai³

et al. 1993

J. Nat. Prod.

107

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“…Further comparison of other physical properties (see Experimental section) confirmed that the isolate was indeed 4. Although portions of the 'H-nmr spectrum of 4 have been reported (16), in Table 1 we have indicated the assignment for each resonance in the 400 MHz spectrum. Determination of the optical rotation of 4 established that it was ( -)-tetrahydropalmatine with the (5) absolute configuration as depicted in Scheme 1 (17,18).…”

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confidence: 99%

Constituents of Parabaena sagittata. Two New Tetrahydroprotoberberine Alkaloids

Ruangrungsi¹,

Lange²,

Lee³

1986

J. Nat. Prod.

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The plant is a climber indigenous to northern Thailand and has been used by the hill tribes for medicinal purposes. Three of the components are known natural products: the cyclohexanepentol, (+ )-protoquercitol (1); the tetrahydroprotoberberine, (-)-tetrahydropalmatine (4); and the protoberberine, berberíne. The other two components are previously unreported tetrahydroprotoberberines and have been given the names (-)-0-methylthaicanine ( 2) and ( -)-thaicanine (3)• Their structures were assigned after detailed analysis of their 'Hand 13C-nmr spectra. Methylation of 3 was shown to yield 2; 2 and 3 are the first reported examples of protoberberines with substituents at the 4-position.Parabaena sagittata Miers (Menispermaceae) is a lofty climber indigenous to the northern part of Thailand and has been used by the hill tribes of this region for medicinal purposes (2). A decoction of stems and leaves affords a treatment for jaundice, indigestion, and painful intestinal disturbances. All parts of the plant may be used as a febrifuge and tonic. There have been no previous reports of any phytochemical or pharmacological studies on this species, but a recent tic screening of P. sagittata Mooney suggested the presence of magnoflorine in the petiole (3). In this report, we describe the structural elucidation of five components isolated from the leaves of P. sagittata Miers. Two of these components are alkaloids not previously reported.The colorless crystalline solid, 1, was isolated as described in the Experimental section and was found to be the cyclohexanepentol (+ )-protoquercitol (1) on the basis of the data reported below. Our 400 MHz 'H-nmr spectrum of this cyclitol was essentially the same as that previously reported at 220 MHz (4). The 13C-nmr spectrum of 1 was reported recently ( 5), but two of the six carbon resonances could not be assigned unambiguously. We have found that 1H-13C shift-correlated 2-D nmr spectroscopy (6,7)showed clearly that the multiplet at 3.59 ppm assigned to -1 (4) was associated with the 13C resonance at 68.9 ppm and that the doublet of doublets at 3.85 for H-5 was attached to the carbon resonating at 68.6. Thus, we have been able to assign all six resonances, and these are reported in the Experimental section. The isolation of ( + )-protoquercitol from the family Menispermaceae has been reported previously (8,9)•

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“…um 10 ppm (3a-c) und 13 pprn (3g-i) gefunden werden. Charakteristisch iat die Signalfolge der Protonen in den Positionen C(5) und C (7) des heterocyclischen Sechsringes, fur den in Analogie zum Cyclohexen eine Halbsesselkonformation diskutiert werden kann. Von diesen Protonen, die aufgrund ihrer Stellung magnetisch nicht aquivalent sind, ergibt H-7ax zwischen 3,79-3,98 pprn jeweils ein leicht verbreitertes Singulett.…”

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