Syntheses of isosophoramine and lycopodinoid hydrojulolidines

A seven-step, stereoselective, total synthesis of the ladybug defensive substance myrrhine (5) from 2,4,6-collidine is presented. Successive alkylation and acylation of 2,4,6-collidine followed by ketalization provides 2-(3-[2-(1,3-dioxolanyl)]propyl)-6-(2-methyl-2-[1,3-dioxolanyl]methyl)-4-methylpyridine (14). Sodium–alcohol reduction gives the corresponding all-cis piperidine 17. Hydrolysis of 17 followed by acid-catalyzed cyclization provides ketone 26. Reduction of the carbonyl group in 26 gives myrrhine (5). Cyclization using pyrrolidine – acetic acid gives a mixture of ketones (26 and 31). Reduction of 31 gives (±)-hippodamine (4). Oxidation of (±)-hippodamine with peracid gives (±)-convergine (3).

mentioning

confidence: 85%

“…Une alkylation et une acylation de lacollidine-2,4,6 suivies par une acCtalisation fournit la ([(dioxolanyl-l,3)-21-3 propy1)-2 (rnithyl-2[dioxolanyl-1,3]-2 mCthyl)-6 methyl-4 pyridine (14). La rCduction par le sodium dans I'Cthanol conduit h la piperidine toute cis correspondante (17). L'hydrolyse de 17, suivie par une cyclisation acido catalysie, fournit la cCtone 26.…”

unclassified

A total synthesis of myrrhine, (±)-hippodamine, and (±)-convergine

Ayer¹,

Dawe²,

Eisner³

et al. 1976

“…The less intense set of signals shows two signals at 6 40.0 and 44.6 ppm. Signals in this spectral region are absent from the spectra of the trans fused free base (14)(15)(16)(17)(18) or the trans fused salt (15) but are present in the cis fused salt (15). The signal set of lower intensity is thus due to the cis fused salt, which is the less abundant (ca.…”

Section: Figmentioning

confidence: 98%

Biosynthesis of the lupine alkaloids. I. Lupinine

Golebiewski¹,

Spenser²

1985

The mode of incorporation into lupinine of cadaverine, intramolecularly doubly labelled with,15N and with,13C at the C-atom adjacent to 15N, i.e., 13C, 15N-"bond-labelled", was determined by,13C nmr spectroscopy; lupinine is generated from two cadaverine-derived C5-units by a route which excludes a "dimeric" intermediate with C2v symmetry. The mode of incorporation of 2H from L-(2-2H)lysine, from (R)- and (S)-(1-2H)cadaverine, and from (2-2H)-Δ1-piperideine into lupinine was determined by 2H nmr spectroscopy. The results corroborate the conclusions from the 13C,15N experiment and they establish the stereochemistry of six of the steps in the biosynthetic conversion of L-lysine into lupinine.

“…Carbon-13 magnetic resonance (c.m.r.) is now emerging as a most attractive complimentary technique for structural elucidation (3,4) of the alkaloids because of the sensitivity of the I3C shielding parameter to slight geometric alterations.…”

Section: Introductionmentioning

confidence: 99%

Carbon-13 Nuclear Magnetic Resonance Studies of Some Lycopodium Alkaloids

Nakashima¹,

Singer²,

Browne³

et al. 1975

Chem. 53,1936 (1975).The natural abundance 13C magnetic resonance spectra of some Lycopodium alkaloids have been determined at both 25.15 and 22.63 MHz. By using standard techniques it has been possible to make self-consistent assignments of almost all of the resonances. The results suggest some interesting conclusions regarding the stereochemistry of some of the alkaloids and have been used to confirm the stereochemical assignment at C-12 in sauroxine and to assign the preferred conformation (axial) of the N-methyl group in the obscurines and N-methyllycodine. THOMAS T. NAKASHIMA, PETER P. SINGER, LOIS M. BROWNE et WILLIAM A. AYER. Can. J. Chem. 53,1936Chem. 53, (1975.On a determine, i 25.15 et 22.63 MHz, les spectres de resonance magnetique nucleaire du 13C en abondance naturelle de quelques alkaloides Lycopodium. Utilisant les techniques habituelles, on a pu faire des attributions cohkrentes de pratiquement toutes les resonances. Les resultats obtenus suggkrent quelques conclusions interessantes concernant la stereochimie de quelqu'uns des alkaloides et ces rCsultats ont etC utilisb pour confirmer I'attribution stereochimiqueen C-12 dans la sauroxine et pour attribuer la conformation priviligik (axiale) du groupe N-methyle des obscurines et de la N-methyllycodine.[Traduit par le journal]