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Ostatnie postępy w syntezie alkaloidów tropanowych i pochodnych tropanu

Sidorowicz K., Kropiwnicki K., Łaźny R.

Wiadomości Chemiczne

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2015

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[Z] 69, 11-12

1019--1045

EN

Tropane alkaloids are a long-known class of compounds possessing an 8-azabicyclo[ 3.2.1]octane skeleton. Many tropane alkaloids posses biological activity (anticholinergic, anti-Parkinsonian, hypotensive), and as such had a significant influence on medicine and played a notable role in the development of organic chemistry [1]. The most known representatives of biologically active tropane alkaloids are: cocaine, atropine, scopolamine, ecgonine, and Bao Gong Teng A. A number of natural tropane alkaloids are chiral compounds, whose preparation in optically active forms is still a big challeng [2]. The biological activity of enantiomers often differs depending on their configurations. Alkaloids are a subject of an intensive research: scopus database contains nearly 200 thousand publications with the word „alkaloid”, and almost 4,500 publications with the phrase „tropane alkaloids” (about half of them have appeared in the last ten years). About 55 papers are devoted to stereoselective synthesis of tropane derivatives in 2000-2015. About half of this concernes stereoselective methods. The organic synthesis of alkaloids has a long history and numerous synthetic approaches to the tropane skeleton have been developed, from the classical synthesis of tropinone by Willstätter at the beginning of the XX century, to more recent developments dealing with asymmetric deprotonation of tropinone with chiral lithium amide bases for the enantioselective synthesis of a range of tropanes [3, 4]. Owing to extensiveness of the field, the current review presents the most interesting, from a synthetic point of view, approaches to tropane derivatives and tropane analogues. Most of the methods of synthesis are long (often several steps), time- and recourses-intensive, and often required elaborate and hardly available starting materials. But there are also notable exceptions, based on the asymmetric deprotonation approach; e.g., from the syntheses of cocaine described in this article, the most efficient one was reported by Lee in 2000 [5]. The concise synthesis (6 steps) gave the unnatural enantiomer of cocaine starting from commercially available tropinone in 78% overall yield. This approach allows to obtain both enantiomers and racemate, by changing type of one reactant only. However, most strategies provide only one enantiomer or racemic mixture of an alkaloid. As can be seen, despite of advances in chemicall science, there is no general way to synthesize majority of the representatives of this group of structurally related compounds.

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Badania strukturalne cyklicznych β-aminoketonów z wykorzystaniem metod obliczeniowych i analizy NMR

Sidorowicz K., Łaźny R.

Chemik

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2015

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Vol. 69, nr 7

401--410

PL

Przestrzenna konfiguracja na atomie azotu w cyklicznych β-aminoketonach powoduje, że związki te mogą występować w dwóch stereoizomerycznych formach, w których podstawniki na tym atomie mogą przyjmować orientację aksjalną lub ekwatorialną w stosunku do pierścienia piperydonu. Stereochemia N-podstawionych bicyklicznych β-aminoketonów była badana za pomocą metod eksperymentalnych i teoretycznych, m.in.: spektroskopia NMR, spektroskopii mikrofalowa, rentgenografii strukturalnej i obliczeń DFT.

EN

Because of pyramidal configuration of the nitrogen atom, tropanes, granatanes, and their derivatives can exist in two stereoisomeric forms, in which N-substituents can be oriented axial or equatorial with respect to the piperidone ring. The N-invertomer stereochemistry of N-substituted bicyclic β-amino ketones has been investigated using experimental, and theoretical methods, such as NMR, microwave spectroscopy, crystallography, and DFT calculations.

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Narzędzia chemii kombinatorycznej. Cz. 4. Synteza asymetryczna na fazie stałej

Łaźny R., Nodzewska A., Żabicka B.

Wiadomości Chemiczne

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2006

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[Z] 60, 3-4

191-255

EN

Solid Phase Asymmetric Synthesis (SPOS) is a recently introduced term embracing all methods of asymmetric synthesis involving use of solid supported substrates and reagents. This review presents basic definitions of asymmetric synthesis and currently used concepts for enatioselective and diastereoselective transformations involving supported synthesis. The concepts of chiral auxiliary, chiral catalyst and chiral reagent are illustrated with selected but fairly comprehensive overview of methods published till January 2005. In particular use of chiral auxiliaries such as oxazolidine derivatives, amines, hydrazines, sulfoxides, sulfinyl amides, sulfoxy imines, carbohydrates and alcohols is covered. Applications of immobilized chiral catalysts to synthesis of carbon-carbon bonds, carbon-hydrogen bonds, carbon--heteroatom bonds and in phase-transfer catalysis is presented with selected reactions due to huge volume of literature in this field. Moreover applications of chiral catalysts and chiral reagents in reactions of immobilized substrates and use of chiral immobilized reagents is also reviewed. The literature review shows that the most popular methods of supported asymmetric synthesis are the alkylation of enolates, aldol reactions, Grignard reactions, cycloadditions, reduetion of ketones, epoxida-tions, olefin dihydroxylation, and phase-transfer catalyzed reactions. There are numerous applications of immobilized chiral catalysts and a substantial number of applications of immobilized chiral auxiliaries. On the other hand there are only scarce reports of applications of chiral reagents and chiral catalysts to the reactions of achiral immobilized substrates.

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Narzędzia chemii kombinatorycznej. Cz 3. Reakcje w syntezie organicznej na fazie stałej

Łaźny R., Łapińska M., Sienkiewicz M.

Wiadomości Chemiczne

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2005

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[Z] 59, 11-12

881--952

EN

Solid Phase Organic Synthesis (SPOS) is a dynamically growing branch of organic synthesis encompusing methods for synthesis of both small molecules and oligomers on solid supports. Synthetically useful organic reactions of substrates immobilized on solid supports constitute a central part of the methodology of solid phase synthesis. This review article presents a representative and fairly comprehensive overview of reactions of supported substrates published till January 2005. The reactions are classified in synthetic terms into functional group interconvertions (FG1, according to type of functional group reacting and prepared) and C-C bond forming reactions (according to reaction type; usually name reaction). Fn particular preparations of halogens, alcohols, ethers, thiols, aldehydes, ketones, acids, esters, amides, phosphines, amines, poliamines, peptides, peptoids, oligonucleotides, and oligosaccharides is covered. Oxidation reactions of alcohols, aldehydes and ketones as well as reduction reactions of aldehydes, ketones, esters, acids, nitro and nitroso compounds are also presented. Only the selected reactions used for preparation of oligonucleotides, oligosaccharides, and polypeptides are covered due to the large volume of literaturę on this topie. The important C-C bond forming reactions such as Mannich, Michael, aldol, Heck, Suzuki, Stille, Sonogashira, Wittig, Horner-Wad-sworth-Emmons, metathesis, carbonyl compound alkylation and acylation reactions are illustrated with examples. Moreover the multicomponent reactions such as Ugi reaction, Hantzsch reaction and Baylis-Hillman reaction are also included in the review. The literature review shows a spectrum of synthetic organic reactions which can be performed on the immobilized substrates and suggests that in principle every reaction could be performed on solid phase. Howeverthe literature review indicates that reactions of polar organometallic reagents, radical reactions, and enantioselective reactions of achiral immobilized substrates are rather rarely used in SPOS.

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Narzędzia chemii kombinatorycznej : nośniki stosowane w syntezie organicznej związków nisko- i wysokocząsteczkowych

Łaźny R., Nodzewska A.

Wiadomości Chemiczne

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2003

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[Z] 57, 7-8

587--625

EN

Progress in combinatorial chemistry is largely determined by development of specific synthetic organic chemistry tools such as solid supports, linkers, polymer supported reactions and methods of analysis, screening and deconvolution of combinatorial libraries. This review article presents basic terms related to polymer supported synthesis, enumerates major advantages of supported reactions, and gives a comprehensive, up to date, overview of support matrices used for immobilization of small and large molecules. The review covers the literature up to September 2002. The supports reviewed include (i) polymeric gels (Merrifield gel, TentaGel, ArgoGelTM, JandaJelTM, PEGA, PEG-PS, PEG-POP, SPOCC, PS-TTEGDA, CLEAR, DendroGel, Pepsyn, and Sucholeiki paramagnetic gel), (ii) soluble polymers (LPS, PEG, ROMP-polymer, PAMAM-dendrymer, Boltron), (iii) macroporous supports (CPG, Pepsyn K, PolyHIPE, ArgoPoreTM) and other developments including SMART reactors, MicroTubeTM, membranes, pins, and cellulose. For most of the supports reviewed basic characteristics such as swelling in different solvents, solvent usability, typical loading, typical anchoring groups, preparation, and recent applications are given or cited. The reviewed literature suggests that the supports most often used for synthesis of small molecules and peptides are based on gel matrices. The variety of available supports, many of which were introduced in the last years, shows that this area of synthetic methodology may grow dynamically in the future.

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Narzędzia chemii kombinatorycznej. Cz.2. Łączniki stosowane w syntezie organicznej na fazie stałej

Łaźny R., Michalak M.

Wiadomości Chemiczne

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2003

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[Z] 57, 11-12

1061--1091

EN

Linkers constitute fundamental tools of polymer supported synthesis and combinatorial chemistry. Synthesis of any compound on solid support requires an efficient method for binding substrate molecules to solid phase and methods for cleavage of product molecules from the support after completion of the synthetic sequence. This review article presents role of linkers in solid-phase synthesis, analogy between linkers and protecting groups, and properties of linkers that need to be considered when planning synthesis of a particular compound on solid support. Basic concepts of linker methodology are presented and illustrated with selected examples. In addition the role of the linker as protection or activation of functional group of the substrate and an element controlling regio- or chemoselectivity is mentioned. The selected, representative examples of classical and recently elaborated linkers are classified according to the condition of cleavage. These include acid sensitive, base or nucleophile sensitive, photolabile, safety catch linkers, traceless linkers and cyclative cleavage linkers.