Identification of C-24 alkyl epimers of marine sterols by <sup>13</sup>C nuclear magnetic resonance spectroscopy

Sright, J. L. C.; McInnes, A. G.; Shimizu, Susana; Smith, Donald G.; Walter, John A.; Idler, D. R.; Khalil, Wagdy K. B.

doi:10.1139/v78-308

Cited by 294 publications

(202 citation statements)

References 12 publications

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“…The 'H nrnr spectrum displayed signals for C3H, C6H, and C8H, virtually identical with those of 9, while the 28CH3 gave rise to a doublet at 8 0.88 ppm, as does the corresponding 28CH, in the known compound 1 (3,4). The most remarkable of the polar sterols isolated from H.…”

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confidence: 85%

“…The five major monohydroxylated sterols were separated and identified by comparison of their spectral characteristics with literature data. The major sterol (85%) of this fraction proved to be (22E,24S)-24-methylcholesta-5,22-dien-3P-ol (22-dehydrocampesterol), 1 (3,4), while other components were identified as (22Z)-24-norcholesta-5,22-dien-3P-ol(4) (1.5%), 24-methylene-5-cholesten-3P-01 (5) (2.4%), 24-isoethylidene-5-cholesten-3P-01 (isofucosterol) (4) (2.9%), and (22E)-24-norcholesta-5,22-dien-3P-01 (4) (0.8%).…”

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confidence: 99%

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Novel sterols from the finger sponge Haliclonaoculata

Findlay¹,

Patil²

1985

Can. J. Chem.

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From the finger sponge, Haliclona oculata (Linnaeus), six new polar sterols have been isolated and their structures determined by chemical and spectroscopic means. These are 3P-hydroxy-cholesta-5,25-dien-24-one (2), 3P-hydroxy-24-methylene-5-cholesten-7-one (6), 24-methylene-5-cholesten-3P,7P-diol (9), 24-methylcholesta-5,22-dien-3P,7P-diol ( l l ) , 24-methylene-5-cholesten-3P,7a-diol (12), and 5~,6-epoxy-24-methylene-cholestan-3~-ol(16). Also shown to be present are the known monohydroxysterols (22E,24S)-24-methylcholesta-5,22-dien-3P-ol (I), (22Z)-24-norcholesta-5,22-dien-3P-ol, 24-methylene-5-cholesten-3p-01, 24-isoethylidene-5-cholesten-3P-01, (22E)-24-norcholesta-5,22-dien-3P-ol and (23E)-cholesta-5.23-dien-3P,25-diol. The structure 14 is tentatively proposed for a novel CZ4 sterol and 8 is suggested for the structure of a compound accompanying 6. JOHN A. FINDLAY et ASHOK D. PATIL. Can. J. Chem. 63, 2406Chem. 63, (1985.On a is016 six nouveaux sttrols polaires de 1'Cponge Haliclona oculata (Linnaeus) et on a determink leurs structures par des mCthodes chimiques et spectroscopiques. I1 s'agit de I'hydroxy-3P cholestadikne-5,25 one-24 (2), de l'hydroxy-3P mCthyl2ne-24 cholesti?ne-5 one-7 (6), du mCthylkne-24 cholestkne-5 diol-3P,7P (9), du mCthyl-24 cholestadi6ne-5,22 diol-3P,7P (11), du mCthylkne-24 cholestkne-5 diol-3P,7a (12) Chemical studies on sponges have shown that they often are a source of novel sterols of biogenetic interest (1, 2). As part of a continuing study of marine natural products from Bay of Fundy organisms, we have examined the sterols of the abundant finger sponge Haliclona oculata (Linnaeus) and now report our findings.Thin-layer chromatography (tlc) of fractions from silica gel column chromatography of a methanol extract of H. oculata showed the presence of substantial amounts of compounds more polar than the monohydroxylated sterol fraction. The five major monohydroxylated sterols were separated and identified by comparison of their spectral characteristics with literature data. The major sterol (85%) of this fraction proved to be (22E,24S)-24-methylcholesta-5,22-dien-3P-ol (22-dehydrocampesterol), 1 (3, 4), while other components were identified as (22Z)-24-norcholesta-5,22-dien-3P-ol(4) (1.5%), 24-methylene-5-cholesten-3P-01 (5) (2.4%), 24-isoethylidene-5-cholesten-3P-01 (isofucosterol) (4) (2.9%), and (22E)-24-norcholesta-5,22-dien-3P-01 (4) (0.8%).Purification of the more polar sterols was achieved by a combination of column chromatography, preparative tlc, and high pressure liquid chromatography (hplc) on silica gel and reverse phase systems. In some cases it was necessary to separate mixtures after acetylation. In this manner we have succeeded in isolating and characterizing the six new sterols 2, 6, 9, 11, 12, and 16, plus the previously reported diene diol4 (6).The novel ketone 2 was purified as its acetate 3 whose ir spectrum (CHCl,) displays strong bands at 1730 and 1670 cm-' attributed to the ester and a,P-unsaturated ketone, respec- For personal use only.

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confidence: 85%

mentioning

confidence: 99%

Novel sterols from the finger sponge Haliclonaoculata

Findlay¹,

Patil²

1985

Can. J. Chem.

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“…The hydroxyl group at C-5 was determined to be α-oriented (Holland & Jahangir, 1983) from the signals observed in the 13 C NMR for C-6 (δ = 133.9) and C-7 (δ = 132.2). The absolute configuration at C-24 was determined to be R (Wright et al, 1978) on the basis of the comparison of 13 C NMR of 1 (δ C = 46.4) and β-sitosterol-3-O-β-D-glucopyranoside (11) (δ C = 46.4, having an R configuration at C-24) in pyridine-d 5 . The configuration of the anomeric carbon was defined as β from the coupling constant of 8.0 Hz.…”

Section: Resultsmentioning

confidence: 99%

Constituents of Nelumbo nucifera leaves and their antimalarial and antifungal activity

Agnihotri

ElSohly

Khan

et al. 2008

Phytochemistry Letters

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From the leaves of Nelumbo nucifera (an aquatic plant), one new compound, 24(R)-ethylcholest-6-ene-5α-ol-3-O-β-D-glucopyranoside (1), along with 11 known metabolites (2-12), were isolated and identified by spectroscopic methods including 1D-and 2D NMR. Antifungal activity for (R)-roemerine (3) (IC 50 /MIC = 4.5/10 μg/mL against Candida albicans) and antimalarial activity for (R)-roemerine (3) and N-methylasimilobine (5) (IC 50 = 0.2 and 4.8 μg/mL for the D6 clone, respectively, and 0.4 and 4.8 μg/mL for the W2 clone, respectively) was observed. None of the compounds were cytotoxic to Vero cells up to a concentration of 23.8 μg/mL. NMR data for 10-eicosanol (7) and 7,11,15-trimethyl-2-hexadecanone (10) are presented for the first time. An analysis of the structure-activity relationship shows that the substituents in position C-1 and C-2 of aporphine alkaloids are crucial for the antimalarial activity.

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“…Os esteróides, o éster 1 e o alcalóide harmana (2) foram identificados através da análise dos dados fornecidos pelos espectros IV e RMN 1 H e 13 C comparados com valores registrados na literatura [9][10][11][12][13][14][15] 16 , como descrito na literatura 8 . A formação deste produto serviu como um dado adicional para confirmação da estrutura proposta.…”

Section: Resultsunclassified

“…Do extrato hexânico foi identificada a mistura de sitostenona e estigmastenona. Os derivados 4a e 5 estão sendo registrados pela primeira vez na literatura.Os esteróides, o éster 1 e o alcalóide harmana (2) foram identificados através da análise dos dados fornecidos pelos espectros IV e RMN 1 H e 13 C comparados com valores registrados na literatura [9][10][11][12][13][14][15] . O espectro de RMN 1 H de 3 mostrou sinais de seis hidrogênios aromáticos da unidade b-carbolínica.…”

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Constituintes químicos isolados de simira glaziovii (K. schum) steyerm. e a atribuição dos deslocamentos químicos dos átomos de carbono e hidrogênio do alcalóide ofiorina e seus derivados

Bastos¹,

Carvalho²,

Velandia³

et al. 2002

Quím. Nova

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Recebido em 18/12/00; aceito em 10/9/01 CHEMICAL CONSTITUENTS FROM SIMIRA GLAZIOVII (K. SCHUM) STEYERM. AND 1 H AND 13 C NMR ASSIGNMENTS OF OPHIORINE AND ITS DERIVATIVES. Chromatographic fractionation of bark extracts from Simira glaziovii (Rubiaceae) afforded the steroids b-sitostenone, stigmastenone, b-sitosterol and stigmasterol, methyl trans-4-hidroxy-3-methoxycinamate (1), the alkaloids harmane (2) and the new stereoisomer of ophiorine B (3). The structures were established by 1 H and 13 C NMR, including 2D techniques and mass spectral analysis, of the natural products and pentaacetyllyalosidic acid (4a) and b-carboline monoterpene tetraacetylglucoside (5, 1,22-lactamlyaloside) derivatives obtained by chemical transformations.Keywords: Simira glaziovii; Rubiaceae; steroids; harmane; (-)-ophiorine. INTRODUÇÃOPlantas do gênero Simira vem despertando interesse devido principalmente às atividades fototóxicas apresentadas por alguns de seus constituintes químicos e pelas informações etnomédicas sobre o tratamento de manchas na cavidade oral e dentária 1 com cascas frescas de S. rubescens. A literatura registra resultados de estudos químicos das espécies S. Maxonii 2-4 , S. mexicana 5 , S. Salvadorensis 6 e S. rubra 6 . Foram identificados, além de policetídeos, alcalóides fotossenbilizantes furoquinolínicos e b-carbolínicos 5,6 . Os alcalóides harmana, maxonina e estrictosamida aparecem como os mais comuns neste gênero 7 .Este artigo descreve o primeiro estudo fitoquímico de um espécimen de S. glaziovii (K. Schum) Steyerm, que permitiu o isolamento e a caracterização dos esteróides b-sitostenone, estigmastenone, b-sitosterol and estigmasterol, 3,4-dimetoxicinamato de metila (1), o alcalóide harmana (2), conhecido como 1-metil-b-carbolina, aribina, loturina ou passiflorina, isolado anteriormente de Arariba rubra e Passiflora incarnata 7 , e o alcalóide ofiorina B (3), encontrado em Ophiorrhiza japonica e O. kuroiwai (Rubiaceae) 8 . Com exceção do alcalóide harmana, os demais constituintes estão sendo caracterizados pela primeira vez no gênero Simira.O tratamento do alcalóide ofiorina (3), epímero no átomo de carbono C-16 da ofiorina A (3a), com diazometano (CH 2 N 2 ) forneceu o produto rearranjado conhecido como lialosídeo (4). A preparação dos dois novos derivados da ofiorina B (4a e 5) e a análise dos dados espectrométricos de RMN 1 H e 13 C (1D e 2D) permitiu caracterizar o alcalóide 3 e estabelecer a completa atribuição dos deslocamentos químicos dos átomos de hidrogênio e carbono, eliminandose inclusive equívocos registrados na literatura. RESULTADOS E DISCUSSÃOO fracionamento cromatográfico do extrato metanólico das cascas de S. glaziovii forneceu além dos alcalóides harmana (2) e (-)-ofiorina (3), a mistura de b-sitosterol, estigmasterol e 3,4-dimetoxicinamato de metila (1). O alcalóde 3 apresentou dados espectrométricos semelhantes aos da (+)-ofiorina B já registrada na literatura 8 e, levando em consideração de que se trata de um glicosideo natural, identificou-o como o novo estereoisômero deste alcalói...

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Identification of C-24 alkyl epimers of marine sterols by ¹³C nuclear magnetic resonance spectroscopy

Cited by 294 publications

References 12 publications

Novel sterols from the finger sponge Haliclonaoculata

Novel sterols from the finger sponge Haliclonaoculata

Constituents of Nelumbo nucifera leaves and their antimalarial and antifungal activity

Constituintes químicos isolados de simira glaziovii (K. schum) steyerm. e a atribuição dos deslocamentos químicos dos átomos de carbono e hidrogênio do alcalóide ofiorina e seus derivados

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Identification of C-24 alkyl epimers of marine sterols by 13C nuclear magnetic resonance spectroscopy

Cited by 294 publications

References 12 publications

Novel sterols from the finger sponge Haliclonaoculata

Novel sterols from the finger sponge Haliclonaoculata

Constituents of Nelumbo nucifera leaves and their antimalarial and antifungal activity

Constituintes químicos isolados de simira glaziovii (K. schum) steyerm. e a atribuição dos deslocamentos químicos dos átomos de carbono e hidrogênio do alcalóide ofiorina e seus derivados

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Identification of C-24 alkyl epimers of marine sterols by ¹³C nuclear magnetic resonance spectroscopy