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Sceletium alkaloids synthesis

Scheme 11.29. Total synthesis of the Sceletium alkaloid (—)-mesembrine 112 [75],... Scheme 11.29. Total synthesis of the Sceletium alkaloid (—)-mesembrine 112 [75],...
Sceletium Alkaloids.—Another synthesis of ( )-mesembrine has been described,9 and also the first total synthesis of (—)-mesembranone (ll),10 summarized in Scheme 1. [Pg.31]

A review entitled General Methods of Alkaloid Synthesis includes pyrrolidine, pyridine, and Sceletium alkaloids.1 Another summarizes nitrogen-containing compounds in tobacco and tobacco smoke, and includes some pyrroles, pyrrolidines, pyridines, and alkaloids related to nicotine.2... [Pg.37]

Sceletium Alkaloids.—A new synthesis of (+)-mesembrine has been reported it uses a chiral y-lactone as a synthon." An alternative synthesis of ( )-sceletium alkaloid A4 has also been described.12... [Pg.38]

Confalone has successfully utilized the deprotonation route (Section II,D) for the synthesis of sceletium alkaloid A4 (84JA7175). Deprotonation of... [Pg.341]

The synthesis of mesembrine-type alkaloids belonging to the Sceletium alkaloid family has been carried out extensively in order to seek a... [Pg.402]

Sceletium Alkaloids.—Full details of an earlier briefly reported synthesis of ( )-mesembrine (3) have been published and a new synthesis has been described. The latter is outlined in Scheme 1 A new Sceletium alkaloid has been isolated from S. namaquense. It has been formulated as (4) on spectral evidence, the assignment of structure being confirmed by direct spectral comparison between the natural base and racemic (4), synthesized earlier. Channaine, another alkaloid of this family, from S. tortuosum, has structure (5) on the basis of an X-ray diffraction analysis of its hexahydrate. It may be an artefact arising from the condensation of a pair of iV-desmethylmesembrenone molecules (6) during isolation. ... [Pg.31]

Sceletium Alkaloids.— The total synthesis of ( )-sceletium alkaloid A4 (10) has been described (Scheme 1). A parallel sequence afforded the 3 -demethoxy-alkaloid. ... [Pg.36]

Alkaloids of the group have been reviewed/ and an account of lactone alkaloids of the Amaryllidaceae has been published/ A concise account of recent developments in the synthesis of Amaryllidaceae alkaloids has appeared/ Contrary to previous practice, Sceletium alkaloids and related compounds are classified as pyrrolidine derivatives and discussed in Chapter 2. The Amaryllidaceae alkaloid cherylline is included in the account of isoquinoline alkaloids (Chapter 8). [Pg.137]

The synthesis of 1-arylcyclopropylimines has been improved (34), and their conversion to A - or A -pyrrolines for further elaboration wiA methyl vinyl ketone and methyl vinyl ketone analogs has been brilliantly employed by Stevens and his co-workers for eflScient syntheses of not only Sceletium alkaloids and the structurally related alkaloids of the Amaryllidaceae family, but alkaloids of diverse structure representing other alkaloid families (46). [Pg.38]

The application of the annelation of endocyclic enamines to the Sceletium alkaloids is exemplified in the synthesis of ( )-Joubertiamine (33), ( )-0-... [Pg.38]

Stevens and co-workers (40) have extended their fundamental approach from the earlier described synthesis of Sceletium alkaloids by employing the... [Pg.51]

Scheme 29. Synthesis of Sceletium alkaloid and a related dihydropyridtme via the endocyclic enamine route. Scheme 29. Synthesis of Sceletium alkaloid and a related dihydropyridtme via the endocyclic enamine route.
Stevens, R. V. Lesko, P. M. Lapalme, R. General Methods of Alkaloid Synthesis. XI. Total Synthesis of the Sceletium Alkaloid A-4 and an Improved Synthesis of ( )-Mesembrine J. Orjf. Chem. 1975, 40, 3495-3498. [Pg.244]

Confalone et al. (85) also made use of an intramolecular cycloaddition step in the construction of a range of tri- and tetracyclic products. Phenyl allyl ethers, of the type shown in Scheme 3.94, underwent dehydrative condensation with the requisite amine to furnish the intermediate ylides, which suffered cycloaddition resulting in 285 and 286 in essentially quantitative yield. The ratio of cis/trans fused products was in the range of 10 1. Such a process has been developed to construct the alkaloid (+ / ) sceletium A4 by reaction of the intermediate 287 with amine 288 via the cycloaddition protocol already developed, followed by further chemical manipulation, in an efficient five step synthesis (Scheme 3.94). [Pg.231]

Mesembrine (-)-Mesembrine (12) is an octahydroindole alkaloid isolated from certain plants of the Sceletium genus, namely S. namaquense, S. strictum and S. tortuosum The mesembrine sttucture has been established as 12. Mesembrine was synthesized from noncarbohydrate, and its synthesis from D-mannitol has been presented herein. [Pg.364]

The spectral data, in conjunction with comparisons with the structural features of Sceletium A4, suggested that the new base was represented by structure 53. A racemic compound possesing this structure had been previously synthesized by Stevens and co-workers (40) in their studies leading to the synthesis of the A4 alkaloid. A direct comparison of samples of the two alkaloids revealed their identity and vihdicated Professor Stevens prediction that the dihydropyridone alkaloid would indeed occur as a natural product (40). [Pg.31]


See other pages where Sceletium alkaloids synthesis is mentioned: [Pg.582]    [Pg.1]    [Pg.33]    [Pg.33]    [Pg.241]    [Pg.872]    [Pg.928]   
See also in sourсe #XX -- [ Pg.45 , Pg.341 ]

See also in sourсe #XX -- [ Pg.333 ]




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Sceletium alkaloids

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