Structure and synthesis of leontidine

Iskandarov, S.; Shaimardanov, R. A.; Yunusov, S. Yu.

doi:10.1007/bf00568420

Cited by 2 publications

(2 citation statements)

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“…The synthesis of epibaptifoline ( B ) and baptifoline ( A ) started with 11‐allylcytisine ( 12 , Scheme ), prepared according to Scheme , . Following Bohlmann's original procedure, the tricyclic alkaloid 12 was simply treated with aqueous formaldehyde in a phosphate buffer (pH = 5), which delivered synthetic epibaptifoline ( B ) in high 86 % yield as a single diastereomer ( dr > 98:2, structure 5b , assignment see below).…”

Section: Resultsmentioning

confidence: 99%

The Hydroxylated, Tetracyclic Bisquinolizidine Alkaloids Baptifoline and Epibaptifoline: Enantioselective Synthesis and Unambiguous Assignment of their Configuration at C‐13

2018

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The epimeric bisquinolizidines baptifoline and epibaptifoline are C‐13 hydroxylated derivatives of the well‐known lupine alkaloid anagyrine. We synthesized both compounds from 11‐allylcytisine and determined their uncertain configuration at the C‐13 stereocenter by NMR, chemical transformation, and X‐ray. The alcohol function was found to be in endo (α) position in baptifoline (configuration: 7R, 9R, 11R, 13R) and in exo (β) position in epibaptifoline (configuration: 7R, 9R, 11R, 13S).

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Section: Resultsmentioning

confidence: 99%

The Hydroxylated, Tetracyclic Bisquinolizidine Alkaloids Baptifoline and Epibaptifoline: Enantioselective Synthesis and Unambiguous Assignment of their Configuration at C‐13

2018

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“…The first syntheses of these alkaloids were done in the context of their (stereo)structure elucidation. Santamaria and Khuong‐Huu prepared camoensidine ( 11 ) from lupanine ( 2 ) by formal ring contraction (4 steps, 7 % yield), [6g] while Yunusov's route from cytisine ( 3 ) to leontidine ( 7 ) included an unintended epimerization (4 steps, 0.4 % yield) [6e,g] . The synthesis of camoensine ( 10 ) by Ohmiya and coworkers is illustrated in Scheme 1 (bottom) [10] .…”

Section: Introductionmentioning

confidence: 99%

Diastereodivergent Synthesis of the Quinolizidine‐Indolizidine Alkaloids of the Leontidine/Camoensine Family

et al. 2021

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Leontidine and camoensine, the main representatives of the small quinolizidine‐indolizidine alkaloid subgroup, are characterized by an inner bispidine system to which a 2‐pyridone and a pyrrolidine are fused on opposite sides. We efficiently synthesized both natural products from the commercially available and abundant alkaloid cytisine, which was converted into the key intermediate, N‐Boc‐11‐oxocytisine, by iodine oxidation and protection. Grignard addition, Paal‐Knorr type cyclization, and hydrogenation delivered endo‐pyrrolidine fused leontidine, while the reversed reaction order, viz. reduction, Sakurai allylation, and ring closure, afforded exo‐pyrrolidine annulated camoensine. Hydrogenation and deoxygenation of the pyridone moieties provided four further alkaloids, tetrahydroleontidine, camoensidine, 11‐epileontidane and leontidane. In addition, the artificial alkaloid isoleontidine, carrying an endo‐fused pyrrolidine on the same side as the pyridone, was prepared from C‐13 oxidized cytisine.

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Structure and synthesis of leontidine

Cited by 2 publications

References 4 publications

The Hydroxylated, Tetracyclic Bisquinolizidine Alkaloids Baptifoline and Epibaptifoline: Enantioselective Synthesis and Unambiguous Assignment of their Configuration at C‐13

The Hydroxylated, Tetracyclic Bisquinolizidine Alkaloids Baptifoline and Epibaptifoline: Enantioselective Synthesis and Unambiguous Assignment of their Configuration at C‐13

Diastereodivergent Synthesis of the Quinolizidine‐Indolizidine Alkaloids of the Leontidine/Camoensine Family

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