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Asymetryczna aminokataliza : użyteczne narzędzie w tworzeniu chemicznej różnorodności

Skrzyńska Anna, Przydacz Artur, Dyguda Mateusz, Topolska Aleksandra, Albrecht Łukasz

Wiadomości Chemiczne

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2020

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[Z] 74, 3-4

255--284

EN

Over the last 20 years asymmetric aminocatalysis has emerged as highly useful and reliable method of asymmetric synthesis. It involves the use of primary or secondary amines as catalysts of various stereoselective transformations of carbonyl substrates. Owing to the diverse activation strategies available in asymmetric aminocatalysis, it became a method of choice when the functionalization of prochiral aldehydes and ketones is considered. As a consequence, a direct and straightforward access to various chiral building blocks is possible that is of relevance to modern stereocontrolled organic synthesis. In the manuscript, the development of various aminocatalytic activation concepts is described and recent, selected contributions to this field of chemistry discussed. Main advantages of these strategies are highlighted providing an overview of this fascinating area of research.

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Anion alkoksyallenowy w syntezie związków naturalnych i ich analogów

Busiak B., Utecht G., Jasiński M.

Wiadomości Chemiczne

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2016

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[Z] 70, 1-2

3--23

EN

Among diverse systems containing multiple bonds, cumulenes are recognized as the most reactive derivatives towards both nucleophilic and electrophilic agents, and for this reason, they are considered as important class of substrates for organic synthesis. Over the last three decades alkoxyallenes have been demonstrated as highly useful C3-building blocks for the construction of numerous N-, O-, and S-containing heterocycles, including enantiomerically pure compounds. Special attention has been paid to lithiated alkoxyallenes as suitable nucleophiles for the reactions with alkyl halides, strained heterocycles, carbonyl compounds and their derivatives. The presence of the allene unit in the initially formed adducts opens up several possibilities in the preparation of more complex systems. In this review, selected applications of lithiated alkoxyallenes in the synthesis of natural products and their analogues are discussed.

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Nowe N-tlenki aldimin jako prekursory związków heterocyklicznych o potencjalnej aktywności biologicznej

Kula K., Dresler E., Demchuk O. M., Jasiński R.

Przemysł Chemiczny

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2015

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T. 94, nr 8

1385-1387

PL

Zsyntezowano serię nowych N-alkilopodstawionych N-tlenków C-(9-antraceno)-imin. Strukturę związków potwierdzono na podstawie danych spektralnych.

EN

N-alkylhydroxyamines were condensed at room temp. With 9-anthracenecarbaldehyde to N-alkyl substituted C-(9-anthracene) imine-N-oxides. The yields of the reaction were 90.5; 94.0 and 67.5% for alkyl substituents Me, PhCH₂ and Bu, resp. The structure of the compds. was confirmed by spectral anal.

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Pochodne pirazolowe : wyzwanie współczesnej chemii akademickiej i przemysłowej

Popielarska H., Myka A., Drabińska B., Gruszeczka A., Kruk J., Kurczab R., Kujawski J.

Przemysł Chemiczny

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2013

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T. 92, nr 6

905--914

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2,4-diphenylthiophene induces mainly base pair mutation in Salmonella Typhimurium

Budzikur K. A., Mielżyńska-Švach D., Góra M., Chachaj A., Pawłowski M., Łuczyński M. K.

Environmental Biotechnology

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2012

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Vol. 8, No. 1

28-31

EN

Heterocyclic aromatic compounds containing sulfur (S-HET), have been detected in air, soil, marine environment and freshwater sediment. Toxicity and mutagenicity data of this class of substances are scarce. The present study focuses on implications of two aryl thiophenes and their mutagenic properties in Salmonella/microsome test. In our experiment only 2,4-diphenylthiophene showed little mutagenic effect in both variants of activaction (+/-S9) in strain TA100. Thiophene ring joined to K-region of phenanthrene did not change the biological activity of 3,6-dimetoxyphenanthro [9,10-c]thiophene and this compound did not show mutagenic potency.

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Physiological characterization of carbazole degrading bacteria isolated from a former gasworks site

Pasternak G., Kołwzan B., Bernard-Baures G, Rybak J, Mrozik A

Environment Protection Engineering

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2012

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Vol. 38, nr 2

121--126

EN

Heterocyclic compounds could remain in the environment as hazardous and resistant pollutants. The aim of this study was to determine the physiological features of Methylobacterium sp. GPE1 strain being able to degrade heterocyclic compounds. Ten various substrates (sugars, alcohols and acids) were used in this assay, for metabolic purposes and eight ones were used as a sole source of carbon and energy. The comparison of the results with data taken from the literature indicated that GPE1 could be a new species of Methylobacterium sp.

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Wykorzystanie kompleksów palladu w syntezie związków heterocyklicznych

Zawisza A.

Wiadomości Chemiczne

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2009

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[Z] 63, 3-4

193-231

EN

Heterocyclic compounds focus an attention for many reasons. Many of them are biologically active compounds, natural products, drugs, synthetic materials and practically useful chemicals [1-5]. Therefore, organic chemists have been making extensive efforts to produce these heterocyclic compounds by developing new and efficient synthetic transformations. Among a variety of new synthetic transformations, transition-metal-catalyzed reactions are very attractive methodologies for synthesis of heterocyclic compounds, since they permit to construct complicated molecules directly from readily accessible starting materials under mild conditions. For this purpose palladium is one of the most widely used transition metals mainly due to the mild reaction conditions used, high yields, a tolerance of a large variety of functional groups, and high regio-, stereo- and enantioselectivity observed [6]. Pd^0-catalyzed allylic alkylations and Pd^II-catalyzed oxidative cyclization of hydroksy(amino)alkene(alkyne)nucleophiles in the intermolecular mode have been particularly notable in this area due to their ability to elicit control in the aforementioned areas, often under very mild conditions. Pd^0-catalyzed intra- or intermolecular heteroannulation through allylic alkylation, the so-called Tsuji-Trost reaction, generally employs allylic acetates [9-14], carbonates [15-29] or vinyl epoxides [30-34] bearing a hydroxy or an amino group as the substrates. Allylsilanes have also been used as precursors of the ?3-allyl intermediates, starting from PdCl2 and CuCl2, affording the corresponding THF and THP derivatives in quite good yields [38-40]. The PdII-catalyzed cyclization of alkenyl alcohols has led to cyclic enols by ?-hydride elimination, or to oxygen heterocycles bearing a vinyl group through a ?-hydroxy elimination, if the alkenol possesses an allyl alcohol moiety. Using this methodology a large variety of oxygen- or nitrogen-containing heterocycles have been obtained even in an asymmetric fashion [51-95].

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A study on the influence of the molecular structure of azines and diazines on retentionin RPHPLC

Baranowska I., Świerczek S.

Zeszyty Naukowe. Chemia / Politechnika Śląska

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1998

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z. 137

95-106

EN

A study was carried out in the retentionof the selected nitrogen heteerocycles in the reversed-phase HP:C mode. The results obtained are in form of the regressional relationship between the retention coefficients and the parameters wich characterize the molecular structure of the analyzed heterocyclic bases. Namely, onecalculated the numericalvalues of logP (considered as a structural descriptor) for 12 heterocyclic bases, and the heterocycles containing 1, 2, and 4 nitrogen atoms in the ring systems, and also for their methyl- and sulphur-substituted derivatives, chromatographed with use of the mixed eluents of different composition. Besides, the relationship between lnk and the contents of the organic modifier (i.e. of methanol) in the binary eluent were regressionally established for the systems emploing the RP-8 and RP-18 stationary phases. An incerease of the affinity of azines and diazines, and also of their methyland sulphur derivatives to stationary phases was established with an increase of the quantitative proportions of water in mobile phase. It was proven that the hydrophobic properties of the analyzed heterocyclic bases mostly depened on the number of the nitrogen atoms in a ring system, whereas the number of the methyl substituents exerts no evident impact on this characteristics.

PL

Praca obejmuje szerokie badania nad retencją związków heterocyklicznych z atomami azotu w pierścieniu w metodzie podziałowej wysoko sprawnej chromatografii cieczowej w układzie odwróconych faz. Przeprowadzone badania pozwalają na określenie zależności pomiędzy współczynikami retencji i parametrami opisującymi strukturę molekularną analizowanych zasad heterocyklicznych. Badania prowadzono na fazach stacjonarnych RP-8 i RP-18 w układzie metanol/woda w różnych stosunkach objętościowych obu składników. W ramach przeprowadzonych w niniejszej pracy badań na RP-8 i RP-18 uzyskano dobre liniowe zależności lnk' od zawartości metanolu w fazie ruchomej. Za pomocą wyznaczonych zależności można w praktyce określić wartości porametru k' dla danego związku stosując fazę ruchomą metanol/woda w dowolnym stosunku objętościowym, gdy znana jest jedynie wartość jego współczynnika k° dla samego metanolu . Ponadto obliczono wartości logP badanych zasad Heterocyklicznych. Parametr ten określa oddziaływania hydrofobowe wpływające w dominującym stopniu na procesy retencji w chromatografii podziałowej. Wyznaczono zależności logP od parametru retencyjnego k dal badanej grupy azyn i diazynna fazach stacjonarnych RP-18 w dwuskładnikowej mieszaninie metanol/woda o różnych stosunkach objętościowych. Stwierdzono zależności liniowe o wysokim współczynniku regresji dla zwiążków zawierających odpowiednio 1, 2 lub 4 atony azotu w pierścieniu.

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Synteza sześcioczłonowych azotowych związków heterocyklicznych w reakcjach cykloaddycji heterodienowej

Bogdanowicz-Szwed K., Krasodomska M.

Wiadomości Chemiczne

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1998

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[Z] 52, 11-12

821--842

EN

In this article we describe new developments in the synthesisof nitrogen heterocycles by hetero-Diels-Alder reaction, covering the literature since 1990. A main point of the discussion is stereoselectivity of the reactions and the preparation of enantiopure compounds either by using dienes and dienophiles carrying a chiral auxiliary or by using Lewis acids. Six-member nitrogen-heterocyclic compounds can be obtained by cycloaddition of aza-1,3-butadienes with carbon dienophiles or by cycloaddition of electron-rich dienes with imines, iminiun ions and nitriles acting as dienophiles. 1-Aza-1,3-butadienes may react as electron-rich as well as electron-deficient dienes in normal cycloaddition or in the cycloaddition with inverse electron demand. E.g. N,N-dimethyl hydrazones prepared from a,b-unsaturated aldehydes 1 reactsmoothly in normal cycloaddition with electron deficient dienophile. However, N-acyl- and N-sulfonyl-imines of a,b-unsaturated aldehydes, e.g. 10, react as electron-deficient dienes in reaction with an inverse electrondermand. Similarly to 1-aza-, 2-aza-1,3-butadienes may react as electron-rich or as electron-deficient components upon appropriate substituation. A versatile approach to functionalized pyrimidines involves the reaction of 1,3-diaza-1,3-butadienes 60 with ketenes. Intramolecular cycloadditions of 1,3-diazadienes 71 efficiently vield complex polycyclic molecules. Theoretical and synthetical studies carried out by van der Plas et al., deal with intramolecular cycloaddition of 5(v-alkynyl)pyrimidines 77. The substrates initially formed bridged adducts, that upon heating release the fused pyridine derivatives and appropriate cyanides by retro Diels-Alder reaction. The second approach to construction of six-membered nitrogen-heterocyclenby Diels-Alder reaction consists in cycloaddition of electron-rich-dienes with iminesor nitriles, that act as dienophiles. Electron deficient imines, e.g. acyl- or sulfonylimines add to many 1,3-dienes in good yields affording tetrahydropyridines. The cycloadditions of nonactivated imines have been investigated with regard to the effects of electronically neutral substituents and the influence of Lewis acids, The recent work in this area deals with asymmetric induction in azadiene reaction. E.g. the utility of chiral imines derived from enantiopure amino acids 93 in cycloaddition with electron-rich diene in presence of Lewis acid lead to pyridone 95 with very good diastereoselectivity (95% de). Chiral Lewis acids were also used in order to carry out enantioselective Diels-Alder reactions starting from achiral substrates and chiral catalyst. E.g. the reaction of imine derived from 3-pyridineformaldehyde 106 and Danishefsky's diene 89 afforded the desired cyclaadduct 107 in high optical purity. Cyanides have been found to be less reactive than imines since the reactions require extremely high temperatures. However, sulfonyl nitriles 112 react with a variety of dienes under much milder conditions affording pyridine derivatives 114.