A synthesis of (±)-Δ2-α-Lycoren-7-one, the key intermediate for the total synthesis of (±)-lycorine

Umezawa, Bunsuke; Hoshino, Osamu; Sawaki, Shohei; Sashida, Haruki; Mori, Kazuhiko; Hamada, Y.; Kotera, K.; Iitaka, Yōichi

doi:10.1016/s0040-4020(01)91130-5

Cited by 29 publications

(4 citation statements)

References 15 publications

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“…In the present compound selenium is regarded as in oxidation state +2. The length of the C-Se bonds, 1.919 (3) and 1.952 (3) Ǻ and the angle between these two bonds, C-Se-C are consistent [15]. The Se-C(Ar) bond distance is somewhat shorter than the Se-C(alkyl) distance as expected [16].…”

Section: Hgclsupporting

confidence: 65%

Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide

Rastogi¹,

Srivastava²,

Asolia³

et al. 2013

JCPT

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PhSe − Na + generated in situ by reduction of PhSeSePh, with sodium borohydride on reaction with N-(2-bromoethyl) phthalimide in N 2 atmosphere results in the formation of N-[2-(phenylseleno)ethyl]phthalimide (L 1). The title compound has been characterized by elemental analysis, FT-IR, 1 H and 13 C NMR techniques. The crystal structure of L 1 has been solved by direct methods and refined by full-matrix least squares. The ligand L 1 crystallize in the monoclinic space group. Selenium forms two Se-C linkages, one is due to Se-C alkyl and the other one to Se-C aryl. Further, the ligation reaction of L 1 with complex 1 is also explored whose identities are characterized by spectroscopic techniques.

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Section: Hgclsupporting

confidence: 65%

Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide

Rastogi¹,

Srivastava²,

Asolia³

et al. 2013

JCPT

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“…The compound 6 was reacted with bromoacetyl chloride in the presence of triethylamine, followed by treatment with hydrochloric acid in THF to offer α‐bromoacetamide derivative 7 in 89% yield (2 steps). According to the modified Umezawa’s intramolecular nucleophilic cyclization method,16g the tetracyclic compound 8 was produced as a single isomer with 67% yield from intermediate 7 by using t‐ BuOK as a base in t‐ BuOH at room temperature for 2 h. Finally, one‐pot reduction of both ketone group and amide group of tetracyclic compound 8 under modified Wolff–Kishner reduction conditions18 gave the target molecule (−)‐α‐lycorane in 74% yield with 99% ee (determined by HPLC). The optical rotation of our synthetic (−)‐α‐lycorane is consistent with the reported data in the literature {[α]${{{22\hfill \atop {\rm D}\hfill}}}$ : −29.8 ( c 1.0, EtOH); lit 16a.…”

Section: Resultsmentioning

confidence: 99%

Catalytic Asymmetric Hydrogenation of α‐Arylcyclohexanones and Total Synthesis of (−)‐α‐Lycorane

Xie

Hou

et al. 2013

Adv Synth Catal

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An efficient catalytic asymmetric hydrogenation of racemic a-arylcyclohexanones with an ethylene ketal group at the 5-position of the cyclohexane ring via dynamic kinetic resolution has been developed, giving chiral a-arylcyclohexanols with two contiguous stereocenters with up to 99% ee and > 99:1 cis/trans-selectivity. Using this highly efficient asymmetric hydrogenation reaction as a key step, (À)-a-lycorane was synthesized in 19.6% overall yield over 13 steps from commercially available starting material.

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“…Azalactone 9 , prepared from 2,3-dimethoxybenzaldehyde and N-acetyl glycine, was hydrolyzed to give pyruvic acid 10a and acetylated enamine 100 as a by-product. The 16-step synthesis of 4 was handicapped by the relatively low yield encountered in the preparation of keto-ester 13 from pyruvic acid 1Ou via Robinson annelation with methyl vinyl ketone (8). The cyclization of acid 20 to ketone 21 in I (CF,CO),0/CF3COOH solution was greatly improved in I comparison to previous work (7n) by conducting the reaction at low temperature.…”

Section: Dbch 4 Frorn 23-dimetlzoxybenzaidehyrle (Sche~ne I )mentioning

confidence: 95%

“…Deprotection of 33 was accomplished by quaternization with methyltriflate, reduction of the quaternary salt with sodium borohydride, and hydrolysis with oxalic acid to give aldehyde 34 (16 formed by ring A in a counterclockwise arrangement with a dihedral angle between the planes of ca. 53" (8). This gives an aS assignment to natural (-)-7s-colchicine, after consideration of the order of the ortho-ortho' substituents of the central bond, according to the chirality rules of Prelog and Helmchen ( I I ) .…”

Section: Dbch 6 By Meyers' Biphenyl Sj~~~tlzesis (Scheme 3 )mentioning

confidence: 99%

Natural products. Antitubulin effect of congeners of N-acetylcolchinyl methyl ether: synthesis of optically active 5-acetamidodeaminocolchinyl methyl ether and of demethoxy analogues of deaminocolchinyl methyl ether

Boyé¹,

Brossi²,

Yeh³

et al. 1992

Can. J. Chem.

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This pelper is cleclicclted lo Dt-. Zdetzc.k (Drtztzy) Vtllet~tcl otr the oc.cnsiotl of his 65th birtlzclc~y 0 . BoyL. A. B~ossr, H. J. C. YEH, E. HAMEI-, B. WEGRZYNSKI. and V . TOOME. Can. J. Chcm. 70, 1237 (1992). Trimethoxy-substituted dihydrodibcnzocycloheptenes 4-7, required for a structure-activity study measuring the inhibition of tubulin polymerization in vitro, were synthesized by four different routes: ( I ) Synthesis of 4 was achieved from 2,3-di~nethoxybenzaldehyde via biphenyl aldehyde 17, chain lengthening to propionic acid 20, acid-catalyzed cyclization toward kctone 21, and removal of the carbonyl group. Mapping and full characterization of the colchicine binding site on tubulin remains a challenging and multifaceted research project (1, 2). Modification of natural (-)-(as, 7 s ) colchicine 1 or the parent compound N-acetylcolchinol methyl ether 2 offers a possibility to gain valuable infor~nation on how these lnolecules bind to tubulin and inhibit its polymerization. Phenolic congeners of colchicine 1, especially I-demethylcolchicine, were found to be less potent than '~u t h o r to whom correspondence may be addressed.colchicine itself (1-4) as inhibitors of tubulin polymerization, with activity partially restored on esterification ( 5 , 6). After the finding of the high potency of 6,7-dihydro-l,2,3,9-tetramethoxy-5H-dibenzo[u,c]cycloheptene (DBCH) 3 (7~11, the systematic synthesis of its deinethoxy derivatives 4-7 was undertaken in order to investigate the contribution of each aromatic oxygen atom in the binding process. The acetamido group in 1 and 2 is not required for binding to tubulin, as indicated by the high activity of compound 3 (7u). The investigation included a synthesis of the optically active amides 8 a , 0 , with the acetamido group at C ( 5 ) . Determination of their absolute configurations, a primary factor in tubulin binding ability, was made by ' H NMR and CD. Can. J. Chem. Downloaded from www.nrcresearchpress.com by 34.212.246.108 on 05/11/18For personal use only.

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A synthesis of (±)-Δ2-α-Lycoren-7-one, the key intermediate for the total synthesis of (±)-lycorine

Cited by 29 publications

References 15 publications

Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide

Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide

Catalytic Asymmetric Hydrogenation of α‐Arylcyclohexanones and Total Synthesis of (−)‐α‐Lycorane

Natural products. Antitubulin effect of congeners of N-acetylcolchinyl methyl ether: synthesis of optically active 5-acetamidodeaminocolchinyl methyl ether and of demethoxy analogues of deaminocolchinyl methyl ether

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A synthesis of (±)-Δ2-α-Lycoren-7-one, the key intermediate for the total synthesis of (±)-lycorine

Cited by 29 publications

References 15 publications

Synthesis, Spectral Characterization and Ligation of &lt;i&gt;N&lt;/i&gt;-[2-(Phenylseleno)ethyl]phthalimide

Synthesis, Spectral Characterization and Ligation of &lt;i&gt;N&lt;/i&gt;-[2-(Phenylseleno)ethyl]phthalimide

Catalytic Asymmetric Hydrogenation of α‐Arylcyclohexanones and Total Synthesis of (−)‐α‐Lycorane

Natural products. Antitubulin effect of congeners of N-acetylcolchinyl methyl ether: synthesis of optically active 5-acetamidodeaminocolchinyl methyl ether and of demethoxy analogues of deaminocolchinyl methyl ether

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Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide

Synthesis, Spectral Characterization and Ligation of <i>N</i>-[2-(Phenylseleno)ethyl]phthalimide