- Concise synthesis of (±)-cytisine via lithiation of N-Boc-bispidine
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(Chemical Equation Presented) (±)-Cytisine has been synthesized in 19% overall yield via a six-step approach from commercially available materials. Key features of this new strategy are as follows: (i) initial construction of the bispidine core, (ii) lithiation-transmetalation-allylation of an N-Boc-bispidine, and (iii) a Pd/C-mediated dihydropyridone oxidation-N- debenzylation process.
- Stead, Darren,O'Brien, Peter,Sanderson, Adam J.
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- (-)-Cytisine: Access to a stereochemically defined and functionally flexible piperidine scaffold
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N-Benzyl cytisine undergoes an efficient C(6)-N(7) cleavage via directed C(6) lithiation, borylation and oxidation to provide a "privileged" heterocyclic core unit comprising a highly functionalised, cis-3,5-disubstituted piperidine in enantiomerically pure form. The potential offered by this unit as a means to explore chemical space has been evaluated and methods have been defined (and illustrated) that allow for selective manipulation of N(1), C(3′), and the pyridone N. The pyridone core can also be diversified via bromination (at C(3′′) and C(5′′)) which is complementary to direct C-H activation based on Ir-catalyzed borylation to provide access to C(4′′). The use of a boronate-based 1,2-migration as an alternative trigger to mediate C(6)-N(7) cleavage of cytisine was evaluated but failed. However, the stability of the intermediate boronate opens a new pathway for the elaboration of cytisine itself using both Matteson homologation and Zweifel olefination.
- Niwetmarin, Worawat,Rego Campello, Hugo,Sparkes, Hazel A.,Aggarwal, Varinder K.,Gallagher, Timothy
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- Synthesis and biological activity of N-benzyl derivatives of cytisine
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The reductive alkylation of cytisine by various aromatic aldehydes was studied. Preliminary pharmacological investigations of the synthesized compounds were performed.
- Rakhimov,Vinogradova,Mirzaev,Vypova,Kazantseva
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- Simple Synthesis of Complex Amines from the Diels-Alder Adducts of (-)-Cytisine
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The Diels Alder reaction of N-benzylcytisine with N-methyland N-benzylmaleimides is 100% endo-selective and gives the corresponding syn- and anti-diastereomers in 11-42% isolated yields. The studies of the reaction progress with LCMS and NMR along with de
- Chuyko, Alexey,Dolgonos, Grygoriy,Fetyukhin, Volodymyr,Lukin, Oleg,Shivanyuk, Alexander
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- Evaluation of sparteine-like chiral diamines in the enantioselective lithiation-electrophilic trapping of an O-alkyl carbamate
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Seven (+)-sparteine-like diamines and (-)-sparteine were evaluated in the diamine-mediated asymmetric lithiation-trapping of an O-alkyl carbamate. The (+)-sparteine-like diamines (≥98: 2 er by chiral shift NMR spectroscopy) were prepared from (-)-cytisine
- Genet, Cedric,McGrath, Matthew J.,O'Brien, Peter
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p. 1376 - 1382
(2007/10/03)
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- Regio- and diastereoselective functionalization of (-)-cytisine
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(-)-N-Benzyl cytisine has been stereoselectively substituted in moderate to high yields on its carbon 6 (Csp3 α to the pyridone nitrogen). The reaction involved the in situ trapping of the carbanion formed by reaction of lithium diisopropyl ami
- Houllier, Nicolas,Gouault, Sonia,Lasne, Marie-Claire,Rouden, Jacques
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p. 11679 - 11686
(2007/10/03)
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- A short synthesis of (±)-cytisine
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The synthesis of racemic cytisine 1 has been completed using (i) N-selective alkylation of 6-bromopyridone with bromide 6 and (ii) Pd(o) mediated intramolecular a-arylation of lactam 8 as key steps to achieve rapid assembly of the tricyclic core skeleton of the lupin alkaloids.
- Botuha, Candice,Galley, Carl M. S.,Gallagher, Timothy
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p. 1825 - 1826
(2007/10/03)
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- Total synthesis of (±)-cytisine
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(equation presented) The nicotine partial agonist cytisine was prepared in five steps featuring an "in situ" Stille or Suzuki biaryl pyridine coupling. Differentiation of the pyridyl rings was accomplished via selective benzylation and then reduction of a pyridinium ring. The penultimate diazabicyclo[3.3.1]-nonane intermediate was obtained with high diastereoselectivity. A similar sequence has been employed for the synthesis of novel derivative 9-methoxycytisine.
- O'Neill, Brian T.,Yohannes, Daniel,Bundesmann, Mark W.,Arnold, Eric P.
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p. 4201 - 4204
(2007/10/03)
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- Synthesis and preliminary pharmacological evaluation of some cytisine derivatives
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Thirty-one N-derivatives of cytisine were prepared in order to modify its pharmacological profile and to obtain compounds of potential therapeutic interest either at a peripheral or central level, particularly as nicotinic ligands with improved ability to cross the blood-brain barrier. Actually, with the introduction of different kinds of substituent on the basic nitrogen of cytisine a variety of activities were observed, both in vivo (analgesic, dopamine antagonism, antihypertensive, inhibition of stress-induced ulcers, antiinflammatory, protection from PAF-induced mortality, hypoglycemic) and in vitro (positive cardio-inotropic, β-adrenergic antagonism, α1- and α2-antagonism, inhibition of PAF-induced platelet aggregation). Six randomly selected compounds were tested for the ability to recognize a central nicotinic receptor and four of them exhibited K(i) values in the range 30-163 nM.
- Canu Boido, Caterina,Sparatore, Fabio
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p. 438 - 451
(2007/10/03)
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