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1
Content available Preparation of highly pure cyclo-polylactides by optimization of the copper-catalyzed azide-alkyne cycloaddition reaction
Liénard R., Josse T., De Winter J., Dubois F., Gerbaux P., Coulembier O.
Polimery
|
2017
|
T. 62, nr 4
283--290
EN
This work reports on the preparation of highly pure cyclo-polylactides (Mn ≈ 4 000 g • mol-1) by the optimization of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction applied on α-azide-ω-alkyne linear polylactide (PLA) precursors. By adjusting parameters such as the rate of reactant addition and the catalyst loading, monocyclic PLA's with a degree of purity of 93 % are obtained in few minutes. Highly pure monocycles (purity as high as 99.9 %) are also possibly prepared in few hours.
PL
Opisano optymalizację syntezy cyklopolilaktydów w katalizowanej miedzią(I) reakcji cykloaddycji azydku do alkinu (CuAAC), której celem było uzyskanie polimerów o wysokiej czystości iśrednim ciężarze cząsteczkowym Mn ≈ 4 000 g • mol-1. Do reakcji użyto prekursorów, którymi były liniowe α-azydo-ω-alkinowe polilaktydy (PLA). Dobrano warunki syntezy, takie jak szybkość dodawania reagenta oraz ilość używanego katalizatora, które pozwalają na otrzymanie w ciągu kilku minut monocyklicznego PLA o stopniu czystości 93 %. Prowadząc syntezę w ciągu kilku godzin można otrzymać monocykliczny polimer o czystości do 99,9 %.
2
Content available remote Optymalizacja procesu otrzymywania 1,3,4-trimetylocykloheks-3-eno-1-karboksylanu metylu
Marshalok H., Kostiv I., Polyuzhin I., Marshalok O., Vytrykush N.
Przemysł Chemiczny
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2016
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T. 95, nr 4
745--750
PL
Doświadczalnie i za pomocą metody modelowania matematycznego ustalono optymalne warunki oraz wydajność technologicznego procesu otrzymywania 1,3,4-trimetylocykloheks-3-eno-1-karboksylanu metylu.
EN
2,3-Dimethylbuta-1,3-diene was cyclized with Me metacrylate (mole ratio 1:1 to 1.5:1) to the title ester at 403–433 K for 3.5 to 6.5 h. The optimum conditions of the reaction were detd. (yield 73% by mass).
3
Content available remote Wykorzystanie kompleksów palladu w syntezie związków heterocyklicznych
Zawisza A.
Wiadomości Chemiczne
|
2009
|
[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].
4
Synthesis of Complex Bicyclo[4.3.0]nonene Derivatives from Sugar Allyltins; Sugar Mimetics Derived from D-Glucose
Jarosz S., Jędra S.
Polish Journal of Chemistry
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2009
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Vol. 83, nr 10
1757-1764
EN
Controlled decomposition of sugar allyltin: methyl 2,3,4-tri-O-benzyl- 6,7,8- tri -deoxy-8-(tri-n-butyl)stannyl-alfa-D-gluco-oct-6(E)-eno-hexo-1,5-pyranoside af forded the corresponding dienoaldehyde with the D-xylo-configuration and the E-geometry across the internal double bond. Reaction of this intermediate with Ph3P=CH-CO2Me provided a triene, which under went cyclization to the bicyclic products: derivatives of bicyclo[4.3.0]nonatriene. Stereochemical aspects of this cyclization, as well as some transformations leading to carbobicyclic sugar mimics, are discussed.
5
Synthesis and Cyclization of N-{2-[(2-Carboxyethyl)sulfanylphenyl]}-beta-alanines
Rutkauskas K., Kantminiene K., Beresnevieius Z. J.
Polish Journal of Chemistry
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2008
|
Vol. 82, nr 12
2341-2347
EN
The reaction of methyl- and methoxyaminobenzenethiols with acrylic acid resulted in formation of 8-methyl- and 8-methoxy-2,3-dihydro-1,5-benzothiazepin-4(5H)-ones, N-{2-[(2-carboxyethyl)sulfanyl]-4-methylphenyl}-b-alanine and 3-[(8-methoxy- 4- oxo-3,4-dihydro-1,5-benzothiazepin-5(2H)-yl]propanoic acid. Their cyclization to N-(5-methyl-4-oxo-3,4-dihydro-2H-thiochromen-8-yl)-b-alanine, 5-methyl- 9,10- dihydro-2Hthiopyrano[3,2-h]quinoline-4,7(3H,8H)-dione and 10-methyl- 2,3,6,7- tetrahydro-4H,8H-[1,4]thiazepino[2,3,4-ij]quinoline-4,8-dione is described.
6
Synthesis of 1,3-Oxaselenan-2-imines from Isoselenocyanates
Sommen G., Heimgartner H.
Polish Journal of Chemistry
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2007
|
Vol. 81, nr 8
1413-1418
EN
The reactions of aryl isoselenocyanates 1 with 3-chloropropan-1-ol (8) in the presence of sodium hydride in dichloromethane at room temperature gave 1,3-oxaselenan-2-imines 10 in fair yield. A reaction mechanism via nucleophilic attack of the alcoholate at the isoselenocyanate 1, followed by an 6-exo-tet cyclization, is most likely.
7
Lactones 17. Synthesis of Bicyclic Lactones with the Methyl- or gem-Dimethylcyclopropane System
Obara R., Szumny A., Żołnierczyk A., Olejniczak T., Białońska A., Ciunik Z., Wawrzeńczyk C.
Polish Journal of Chemistry
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2005
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Vol. 79 / nr 6
981-993
EN
A new method of synthesis of bicyclic gamma-lactones with the methyl- or gem-dimethylcyclopropane system from gamma,delta unsaturated esters is described. The reaction of gamma-halo delta- lactones with DBU is the key step of this synthesis. The mechanism of the dehydrohalogenation- cyclization process of gamma-halo-delta-lactones is proposed. The structures of products were confirmed by both spectroscopic and crystallographic methods.
8
Functionalization of the Homoallylic Bridge in Higher Sugar Precursors
Jarosz S., Szewczyk K., Gaweł A., Gomez A., Lopez J.
Polish Journal of Chemistry
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2005
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Vol. 79 / nr 2
231-238
EN
The Barton reduction of the sugar homoallylic xanthate did not afford the expected hydrocarbon, but led to two cyclic products resulting from the attack of initially formed radical onto the olefin fragment of the homoallylic system. The mechanism of such cyclization is discussed.
9
Synthesis of 4,5-Dicyanoimidazoles
Bukowska M., Prejzner J., Szczeciński P.
Polish Journal of Chemistry
|
2004
|
Vol. 78 / nr 3
417-422
EN
The effective procedure of preparation of 2-trifluoromethyl-4,5-dicyanoimidazole (3a) from diaminomaleonitrile (1) and trifluoroacetic anhydride has been elaborated. The syntheses of five other 2-substituted imidazoles from appropriate acyl derivatives of 1 have been attempted. Out of them only 4,5-dicyanoimidazole (3b) could be obtained in good yield.
10
Synthesis of 2-Alkylbenzofurans via Acid-catalyzed Cyclization of 1,1-Dimethoxy-2-phenoxyalkanes
Kwiecień H., Witczak M., Rosiak A.
Polish Journal of Chemistry
|
2004
|
Vol. 78 / nr 2
249-254
EN
Treatment of 2-phenoxyalkanals 1a-e with methanol at room temperature under homoor heterogeneous acid-catalysis conditions leads to formation of diacetal as well as some quantities of appropriate 2-alkylbenzofurans. 2-Alkylbenzofurans3a-e were obtained in high yields viacyclization of the 1,1-dimethoxy-2-phenoxyalkanes 2a-e under mild conditions over Amberlyst 15.
11
Synthesis of 2-Alkyl-5-nitrobenzofurans via 2-(2-Formyl-4-nitrophenoxy)alkanoic Acids
Kwiecień H.
Polish Journal of Chemistry
|
2004
|
Vol. 78 / nr 10
1865-1869
EN
Two reaction methods were employed to prepare alumoxanes of general formula [(RO)AlO]n. The first one from Et3Al, H2O and ROH [R = CH3, (CH3)2CH]; the second one from Et3Al, ROH [R = (CH3)2CH, CH3(CH2)9] and H2O. The properties, chemical composition, aggregation and proposed structure of the final products are discussed based on gel permeation chromatography, molecular weight determination and spectroscopic data.
12
Experimental and Theoretical Studies on Pyrolysis of O-Acetyl Derivatives of beta-phenylcinnamaldehyde and Benzaldehyde Oximes
Mohamed M., Siedlecka M., Suwiński J.
Polish Journal of Chemistry
|
2003
|
Vol. 77 / nr 5
577-590
EN
[ReBr3(py)3]0.42[ReBr2(NO)(py)3]0.58 (1), trans-[ReBr4(OPPh3)2] (2), [ReBr(NO)(dppe)2]Br (3) and orthorhombic polymorph of mer-cis- [Re(NO)Br3(OPPh3)2] (4) complexes have been synthesized by reactions of monoclinic polymorph of mer-cis-[Re(NO)Br3(OPPh3)2] with pyridine, bis(diphenylophosphino) ethane, 2,2_-bipyridine, 1,10-phenanthroline. The NO group in 1 and 4 is coordinated in a linear way. Due to nitrosyl/bromine compositional disorder, the shortening of Re-NO distance [1.68(5) A] and the elongation of N-O bond length [1.38(10) A] are observed in1. The N-O bond length in 4 is extremely short [0.94(1) A], which results probably from steric interactions of two mutually cis OPPh3 molecules and a large discrepancy of Re-O-P angle values.
13
Synthesis of Isoxazolo {3,4-d]pyrimidines from 6-Chloropyrimidine-5-carbaldehydes
Kaminskas A., Dailide M., Tumkevicius S.
Polish Journal of Chemistry
|
2002
|
Vol. 76 / nr 5
725-728
EN
4-Dialkylamino-6-chloro-2-methylthiopyrimidine-5-carbaldehydes with sodium azide in dimethylformamide underwent ring closure reaction to form the corresponding isoxazolo[3,4-d]pyrimidines.
14
Optimization of the parameters of 2-(2-formylphenoxy)hexanoic acid cyclization. Synthesis of 2-alkylbenzofurans
Miszczyszyn M., Kwiecień H.
Polish Journal of Applied Chemistry
|
2002
|
Vol. 46, nr 1
21-29
EN
The intramolecular cyclization of 2-(2-formylphenoxy)hexanoic acid (FPHA) to 2-butylbenzofuran under the Perkin reaction conditions has been investigated. The influence of important parameters on the 2-butylbenzofuran yield in relation to 2-(2-formylphenoxy)hexanoic acid introduced (response function) has been described by regression equations in the form of a second order polynomial. The optimum values of: acetic anhydride to FPHA molar ratio, reaction time, acetic acid to FPHA molar ratio have been determined. 2-Butylbenzofuran and some of benzene-ring-halogenated 2-alkylbenzofurans have been obtained in moderate yields from corresponding 2-(2-formylphenoxy)alkanoic acids with the use of optimal conditions.
15
Content available remote Modelowanie homopolimeryzacji stopniowej - jak udział cykli zależy od definicji modelu
Galina H., Lechowicz J. B.
Polimery
|
2000
|
T. 45, nr 7-8
496-501
PL
Porównano przebiegi tworzenia się cykli w modelowych procesach homopolimeryzacji stopniowej trójfunkcyjnego monomeru. Zastosowano modele perkolacyjne dalekiego zasięgu oraz modele pseudoklasyczne. Scharakteryzowano zmiany udziału cykli w funkcji konwersji w przypadku różnych wartości parametru zasięgu (rys. 2) i różnych wartości stałej giętkości cząsteczek (rys. 3) oraz określono zależność krytycznego stopnia przereagowania w punkcie żelowania od liczby potencjalnych partnerów do reakcji (liczby koordynacyjnej) (rys. 4). Szczególnie widoczna różnica między badanymi modelami występuje w przypadku obliczonych wartości konwersji w punkcie żelowania, która rośnie wraz ze zwiększającą się szybkością powstawania cykli. Omówiono przyczyny powodujące, że obecnie nie można jeszcze uzyskać pełnej zgodności danych doświadczalnych z danymi obliczonymi za pomocą modeli numerycznych.
EN
Cycle formation courses were compared in modelled stepwise . homopolymerizations of a trifunctional monomer. Long-range percolation models and pseudoclassic models were applied. Cycle fraction variations in the conversion function were characterized in relation to the range parameter value (Fig. 2) and to the molecule flexibility constant (Fig. 3); the critical degree of reaction at the gelling stage was defined in relation to the number of potential reaction partners (coordination number) (Fig. 4). A particularly well visible difference between the models applied is pronounced in the conversion values calculated at the gelling point: it rises as the rate of cycle formation is raised. Reasons are given why, at the moment, the numerical models cannot provide full agreement of the observed with the calculated data.
16
A novel type of ring closure of amino-substituted thiocarbonyl ylides
Romański J., Mlostoń G., Linden A., Heimgartner H.
Polish Journal of Chemistry
|
1999
|
vol. 73 nr 3
475-485
EN
The reaction of 4,4-dimethyl-1,3-thiazole-5(4H)-thiones 7a-c with dimethyl 2-diazo-3-(phenyloamino)butanoate (2), prepared from dimethyl fumarate and phenyl azide, in toluene at 800C yielded mixtures of dimethyl 2-(4,5-dihydro-4,4-dimethyl-1,3-thiazol-5-ylidene)-3-(N-phenylamino)butanedioates of type 11 and four diastereoisometric 4,4-dimethyl-9-phenyl-1,6-dithia-3,9-diazaspiro[4,4]non-2-ene-7,8-dicarboxylates of type 12. The formation of the products of type 12 is rationalized by a novel cyclization of intermediate thiocarbonyl ylides 9. The structures of cis-12a, cis-12c, and trans-12c were established by X-ray crystallography.
17
Synthesis and properties of new 2-alkyl-1,4-benzoxazepine derivatives. Part 3. Synthesis and cyclization of 2-(2-carboxyphenoxy)alkanamides
Kwiecień H.
Polish Journal of Chemistry
|
1998
|
Vol. 72, nr 10
2254-2260
EN
A series of novel 2-(2-carboxyphenoxy)alkanamides 4a-f have been obtained as result of condensation of salicylaldehydes with 2-halo esters, amination of prepared esters, 1a-f with methylamine followed by oxidation of amides 3a-f with sodium chlorite. The intramolecular cyclization of amides 4a-f to 1,4-benzoxazepin-3,5-dione system has been investigated.
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