Decahydroquinoline alkaloids

Decahydroquinoline Alkaloids.—Full details of an earlier briefly described synthesis of ( )-pumiliotoxin C have been published.28 Other total syntheses of the same compound have been documented, starting from trans-4-hexenal,29 and from ethyl tra s-buta-l,3-diene-l-carbamate.30 An enantioselective synthesis of natural (-)-pumiliotoxin-C hydrochloride (34) has also been described (Scheme 6),... 

Decahydroquinoline Alkaloids.—A review on the total synthesis of lycopodium alkaloids has appeared it includes syntheses of luciduline.25 Additional total syntheses of ( )-gephyrotoxin26 and ( )-perhydrogephyrotoxin27 have been described, and ( )-depentylperhydrogephyrotoxin has been synthesized via an interesting cyclization of a vinylogous TV-acyliminium ion.28... 

Alkali metal in ammonia reductions of pyrrolobenzodiazepine-5,11-diones give trans-2-aminocyclohexanecarboxylic acid derivatives (e.g., 4) in enantiomerically pure form.2 3 A method for preparation of cis-2-aminocyclohexanecarboxylic acids related to 4 is based on the enantioselective hydrolysis of symmetrical diesters with pig liver esterase.4 cis-2-Aminocyclohexane derivatives have been used for syntheses of aminocyclitol antibiotics.4 5 6-Alkyl-cis-2-aminocyclohexanecarboxylic acids can be prepared by alkali metal in ammonia reduction of pyrrolobenzodiazepine-5,11-diones followed by olefin hydrogenation the cis-decahydroquinoline alkaloid (+)-pumiliotoxin C has been prepared by this methodology.2... 

Decahydroquinoline alkaloids, 206-212 biological activity, 211 occurrence, 211-212 physical and spectral properties, 208-211 structures, 206-211... 

A sequence of tandem-Mannich-Michael reactions and conjugate additions of organocuprates has been used for the synthesis of enantiomerically pure alkaloids such as (—)-dihydro-pinidine 193, the indolizidine alkaloid (5/, 8a/ )-gephyrotoxin 167B 194 and the decahydroquinoline alkaloid 4a- p/-pumiliotoxin C 195 (Figure 10.18) [150]. 

Weymann, M, Schultz-Kukula, M, and Kunz, H, Auxiliary-controlled stereoselective enolate protonation enantioselective synthesis of cis and trans annulated decahydroquinoline alkaloids. Tetrahedron Lett., 39, 7835-7838. 

Decahydroquinoline Alkaloids.—Full details of a synthesis of ( )-pumiliotoxin-C hydrochloride and of its X-ray diffraction analysis, described briefly earlier,have been published. Two new syntheses of the racemic free base (31) have been described the first is outlined in Scheme 7. The final hydrogenation afforded the desired base (31) as major product, a consequence of a high order of stereoselectivity in this step. The second approach (Schemes 8 and 9) uses 1,3-bistrimethylsilyloxy-1,3-dienes as intermediates. In both of the latter pathways the final product is the lactam (32), the conversion of which to ( )-pumiliotoxin-C has already been documented. ... 

Decahydroquinoline "alkaloids" occur in the skins of Neotropical frogs of the Dendrobatidae genus (for a review see J.W. Daly, Fortschr.Chem.Org.Naturst., 1982, 41, 205). These structures, of which purailiotoxin-C (96) is a typical example, are obviously related to the pyridine bases described in Chapter 30. Gephyrotoxin (97) another natural product of this type has also been synthesised (Overman, D. Lesuisse and M. Hashlmoto, J.Amer.chem.Soc., 1983, 105, 5373 J. Royer and H.P. Husson, Tetrahedron Letters, 1985, 26, 1515). 

Overman, L.E., and Jessup. P.J.. Synthetic applications of V-acylamino-l,3-dienes. An efficient stereospecific total synthesis of (//-pumiliotoxin C. and a general entry to cw-decahydroquinoline alkaloids, J. Am. Chem. Soc.. 100. 5179. 1978. 

Decahydroquinoline Alkaloids.—The structure of pumiliotoxin-C (26) has been confirmed by an X-ray diffraction analysis of its hydrochloride/ and by two total syntheses of the racemic base/ The syntheses are outlined in Schemes 5 and 6/ ... 

Decahydroquinoline Alkaloids.—A new decahydroquinoline alkaloid, iso-nitramine (29), has been isolated from Nitraria sibirica, its structure being inferred from spectral measurements. ... 

The decahydroquinoline alkaloid 116 was labeled 195A. Draw a dear three-dimensional representation of 2-ep/-195A. 

Overman, L. E. Jessup. P. J. "Synthetic Applications of A/-Acylamino-1,3-dienes. An Efficient Stereospecific Total Synthesis of c/Z-Pumiliotoxin C, and a General Entry to c/s-Decahydroquinoline Alkaloids" J. Am. Chem. Soc. 1978, 100, 5M9. 

The pumiliotoxins are a group of more than 60 alkaloids isolated from the toxic skin secretions of the frog Dendrobates pumilis and related species. Many of the alkaloids have, as a central feature, the unusual c/s-decahydroquinoline structure, and since they possess interesting neurological activities they are an attractive target for total synthesis. A new total synthesis of rf,/-pumiliotoxin C has been reported. The main feature of the new synthesis is the Diels-Alder reaction of an activated N-acylaminodiene and a crotonaldehyde derivative leading to an intermediate with two chiral centres which can be utilized to control the introduction of the third chiral centre (Scheme 67). The method, which is short and efficient, should be useful in the synthesis of other cis-decahydroquinoline alkaloids. The overall yield of c/,/-pumiliotoxin C was 51%. 

StefFan, B. (1991) Lepadin A, a decahydroquinoline alkaloid from the tunicate Clavelina kpadiformis. Tetrahedron, 47, 8729-8732. 

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