The Absolute Configuration of Halosaline.

Michel, Karl-Heinz; Sandberg, F; Haglid, F.; Norin, T.; Chan, Rosalind P. K.; Craig, J. Cymerman

doi:10.3891/acta.chem.scand.23-3479

Cited by 27 publications

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“…If ring-closure proceeds through a chair-like transition state (e.g. 18,20) the hydrogen atoms at C-5 and C-11 of the newly formed ring in 19 and in 23 5The numbering system for matrine which is adopted in this paper was introduced by Schiitte er al. (3).…”

Section: The Biosynthesis Of Matrinementioning

confidence: 99%

“…Furthermore, an aldotripiperideine of unknown stereochemistry occurs naturally (20). The aldotripiperideine (22) which yields the "prematrine trimer" by intramolecular cyclization is accessible from tetrahydroanabasine and A'-piperideine not only by the route which is forbidden since it is a variant of Only one of these carbons, C-15, has been obtained directly, in the form.of benzoic acid, by treatment of matrine with phenylmagnesium bromide (2) or phenyl lithium (3, 4), followed by chromic acid (2) or permanganate (3, 4) oxidation of the phenyldihydro derivative.…”

Section: The Biosynthesis Of Matrinementioning

confidence: 99%

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Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine

Leeper¹,

Grue-Sørensen²,

Spenser³

1981

Can. J. Chem.

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Label from [6-14C]-Δ1-piperideine is incorporated nonrandomly into the carbon skeleton of the quinolizidine alkaloid, matrine, in Sophora tetraptera and S. microphylla. The distribution of radioactivity was determined by a new chemical degradation sequence. On the basis of the results, one of two previously postulated biogenetic schemes must be discarded. A modified biogenetic scheme is presented which is consistent with the present results and also leads to the correct stereochemistry of matrine.

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Section: The Biosynthesis Of Matrinementioning

confidence: 99%

Section: The Biosynthesis Of Matrinementioning

confidence: 99%

Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine

Leeper¹,

Grue-Sørensen²,

Spenser³

1981

Can. J. Chem.

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“…-11.4 (chloroform, c 1)) is, however, clearly in error. R configurations, inter alia through correlation with pipecolic acid (10,11,13). We assign the homologous levorotatory ketones 4d and 4e the same R absolute configuration from the sign of the rotation and from the similar chromatographic behaviour of the diastereomer isoxazolines throughout the series.…”

mentioning

confidence: 93%

“…1n ref. 11, an optical purity of 90% was determined for a sample of 4c prepared from natural halosaline; the specific rotation value quoted ([a]? -11.4 (chloroform, c 1)) is, however, clearly in error.…”

mentioning

confidence: 99%

Synthesis of enantiomeric β-amino ketones via 1,3-dipolar cycloaddition and chromatographic resolution

Louis¹,

Mill²,

Mancuso³

et al. 1994

Can. J. Chem.

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. 72, 1347 (1994). The cycloaddition reactions of 3,4,5,6-tetrahydropyridine I-oxide 1 with the homochiral alkynyl sulfoxides 60-e proceed in high yield to afford, with low asymmetric induction, mixtures of diastereomeric isoxazolines that are readily separated by column chromatography. ' The resolved isoxazolines can be subsequently converted, by hydrogenolysis, to enantiomeric p-amino ketones.CHANTAL LOUIS, SIBEL MILL, VINCENT MANCUSO et CLAUDE HOOTEL~. Can. J. Chem. 72, 1347Chem. 72, (1994. Les rCactions de cycloaddition entre la 3,4,5,6-tktrahydropyridine I-oxyde 1 et les sulfoxydes acCtylCniques homochiraux 6a-e conduisent avec de bons rendements et une induction asymetrique faible a des mtlanges d'isoxazolines diasttrtoisom&res facilement sCparables par chromatographie sur colonne. Les isoxazolines rCsolues peuvent &tre converties, par hydrogtnolyse, en p-aminocCtones Cnantiomkres.[Traduit par la RCdaction] Introduction ene (6) (Scheme 2). Based on the fact that Grignard reactions p -~~i~~ ketones an important ,-lass o~c o m p o u n~s with chiral sulfinate esters proceed stereospecifically with for which the synthesis deserves interest. In this regard, we preinversion of configuration at the sulfur atom (7), the acet~lenic viously reported a new efficient synthesis based on the observasulfoxides 6a-e are assigned the S configuration; the optical tion that 4-isoxazolines 3 can be viewed as masked p-amino purity and the absolute configuration of 6c-e were previously ketones, which could be released by hydrogenolysis of the confirmed by their conversion into the corresponding alkenyl N-0 bond (1) (Scheme 1). Although 4-isoxazolines have derivatives (6).2 proven to be thermally labile heterocycles and display an arrayThe reaction nitrone 1 with the alkynyl sulfoxides 6a-e of rearrangements (2, 31, we established that under carefully gave mixtures of the diastereomeric isoxazolines 7a-e and 8a-e controlled conditions they can be prepared in good yield by (Scheme 3); the large differences in the R,s allowed the comnitrone-alkyne cycloaddition. ~~~~~~~ of the N-0 plete separation of the individual diastereomers of each pair by bond can be performed by hydrogen in the presence of P d C .flash chromatography silica gel. Typical results are PreApplication of this procedure to the synthesis of sented in and deserve some 2-phenacylpiperidine, for example (4, R = C6H,), proceedsAll the cycloadditions proceed with excellent yields. It from nitrone 1 and pheny lacety lene with 70% overall yield. In

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“…[4][5][6] A methanolic extract of this plant showed strong cytotoxicity in brine shrimp lethality test. 7) On further fractionation, the major cytotoxicity was detected in the chloroform-soluble fraction.…”

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confidence: 99%

Haloxylines A and B, Antifungal and Cholinesterase Inhibiting Piperidine Alkaloids from <i>Haloxylon salicornicum</i>

et al. 2005

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Haloxylon salicornicum (MOQ.-TAND.) Boiss belongs to the family Chenopodiaceae which comprises 100 genera and 1200 species. Most of the members of this family are weedy and grow in waste and unfertile areas of soil. In Pakistan, this family is represented by 35 genera. Only five species of genus Haloxylon are found in Pakistan. Haloxylon salicornicum is a diffuse shrub, pale, much branched, almost leafless, 25-60 cm tall, with woody stem. It is widely distributed in Egypt, Palestine, Jordan, Iraq, Kuwait, Iran, and Pakistan.1) The plant is traditionally reported for its toxicity and applied externally on insect stings.2) The ash of the plant is used for internal ulcers.3) Three alkaloids and a pyranone derivative have so far been reported from this species. [4][5][6] A methanolic extract of this plant showed strong cytotoxicity in brine shrimp lethality test. 7) On further fractionation, the major cytotoxicity was detected in the chloroform-soluble fraction. Further pharmacological screening of this fraction revealed strong antifungal and cholinesterase inhibiting activities. This prompted us to carry out bioassay-guided isolation of bioactive compounds from the chloroform-soluble fraction. As a result of these studies we have isolated two new piperidine alkaloids named as haloxylines A (1) and B (2). Both 1 and 2 showed antifungal and cholinesterase inhibiting activities. Results and DiscussionThe methanolic extract of the whole plant of H. salicornicum was processed as described in Experimental to afford new piperidine alkaloids named as haloxylines A (1) and B (2). Haloxyline A (1) was isolated as colorless crystals (14 mg). The high-resolution (HR) EI-MS of (1) showed the molecular ion peak at m/z 419.3749 (Calcd for C 27 H 49 NO 2 , 419.3763) possessing four degrees of unsaturation. The IR spectrum of 1 showed an amide carbonyl at 1640 cm Ϫ1 and conjugated double bonds at 1620 cm (C-4). All the assignments were confirmed by hetronuclear multiple quantum coherence (HMQC). The cumulative evidences allowed us to assign the structure of haloxyline A (1) as (Z,Z)-1-(22-hydroxy-1-oxo-2,4-docosadienyl) piperidine. The heteronuclear multiple-bond correlations (HMBC) were in exact agreement to the assigned structure.Haloxyline B (2) was also obtained as colorless crystals (12 mg). The molecular formula was established by HR-EI-MS showing molecular ion peak at m/z 435.3701 (Calcd for C 27 H 49 NO 3 , 435.3712) with four degrees of unsaturation. The UV and IR spectrum were almost superimposable to those of 1. The presence of hydroxy substituted piperidine ring was revealed by peaks in EI-MS and HR-EI-MS at m/z 100 and 100.0058 respectively. Therefore, haloxyline B (2) differs from (1) in having additional alcoholic group in the piperidine ring. In 1 H-NMR spectrum the signals of piperidine differed from those of 1. The hydroxymethine proton * To whom correspondence should be addressed. Haloxylines A (1) and B (2), new piperidine alkaloids, have been isolated from the chloroform soluble fraction of Haloxylon salicorni...

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The Absolute Configuration of Halosaline.

Cited by 27 publications

References 0 publications

Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine

Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine

Synthesis of enantiomeric β-amino ketones via 1,3-dipolar cycloaddition and chromatographic resolution

Haloxylines A and B, Antifungal and Cholinesterase Inhibiting Piperidine Alkaloids from <i>Haloxylon salicornicum</i>

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The Absolute Configuration of Halosaline.

Cited by 27 publications

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Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ1-piperideine into matrine

Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ1-piperideine into matrine

Synthesis of enantiomeric β-amino ketones via 1,3-dipolar cycloaddition and chromatographic resolution

Haloxylines A and B, Antifungal and Cholinesterase Inhibiting Piperidine Alkaloids from <i>Haloxylon salicornicum</i>

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Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine

Biosynthesis of the quinolizidine alkaloids. Incorporation of Δ¹-piperideine into matrine