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1

Synteza koroli

Koszarna B., Gryko D.T.

Wiadomości Chemiczne

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2008

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[Z] 62, 3-4

165-185

EN

Corroles, one carbon shorter analogues of porphyrins emerged a few years ago as an independent research area (Fig. 1) [1-3]. Their coordination chemistry, photophysics, synthesis, chemical transformations, electrochemistry and other properties have recently been studied in great detail [7-11]. Discovered in 1964 [15], for many years they have been mainly synthesized via a,c-biladienes cyclization [19-20]. Multistep a,c-biladienes preparation discouraged broader range of chemists from studying corroles (Scheme 2). Since initial reports by Gross [17, 18] and Paolesse [16] revealing one-pot syntheses of meso-substituted corroles from aldehydes and pyrrole, this reaction has been subjected to many refining studies (Scheme 4, 5; Table 2) [23-28]. As a result yields have been improved to ~ 15%. The one-pot synthesis of meso-substitued A3-corroles from aldehydes and pyrroles consists of two independent steps. The first step is an acid-mediated electrophilic substitution to yield a mixture of various aldehyde-pyrrole oligocondensates including bilane (tetrapyrrane) - the direct precursor of corrole (Scheme 6). The second step is the oxidative ring-closure. Maximizing bilane formation while minimizing the formation of dipyrromethanes, tripyrrane and higher oligocondensate is a difficult task due to the similar reactivity of all these compounds [30-32]. Recently new and efficient conditions for the synthesis of meso-substituted corroles have been developed [33]. The first step, namely the reaction of aldehydes with pyrrole, was carried out in a water-methanol mixture in the presence of HCl. A relatively narrow distribution of aldehyde-pyrrole oligocondensates was controlled by their solubility in the reaction medium. After thorough optimization of various reaction parameters high yields of bilanes were obtained. As a result, many A3-corroles were obtained in the highest yield (~25-30%) reported to date. Corroles bearing two various substituents at meso positions were synthesized for the first time from dipyrromethanes and aldehydes (Scheme 10) [35]. This method continues to prevail in the literature [36-38]. Performance of this reaction in H2O/MeOH/HCl mixtures allows to obtain trans-A2B-corroles in yields up to 56% (Scheme 11) [33]. Last developments in the chemistry of corroles make these compounds more accessible than respective porphyrins.

2

Zdolność do polimeryzacji cyklicznych estrów alifatycznych

Duda A., Kowalski A.

Polimery

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2007

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T. 52, nr 7-8

485-495

PL

Na podstawie przeglądu literatury przedyskutowano podstawowe czynniki wpływające na zdolność cyklicznych estrów alifatycznych (laktonów, laktydów i węglanów) do polimeryzacji. Wyróżniono: (a) czynniki termodynamiczne, związane głównie z naprężeniem monomeru i liczbą stopni swobody jednostek powtarzalnych polimeru oraz (b) czynniki kinetyczne, wynikające z dostępności mechanizmu zapewniającego wystarczającą szybkość polimeryzacji. Zwrócono uwagę na fakt, iż uwarunkowana termodynamicznie niezdolność cyklicznego estru do polimeryzacji nie oznacza niezdolności do reakcji otwarcia pierścienia, gdyż możliwa jest synteza wielkocząsteczkowych kopolimerów zawierających do 50 % mol. jednostek powtarzalnych pochodzących od monomeru niezdolnego do homopolimeryzacji. Analiza uwarunkowań kinetycznych wykazała, iż nie ma jednolitej korelacji między reaktywnością a wymiarem pierścienia monomeru i może wystąpić odwrócenie szeregu reaktywności monomerów w zależności od mechanizmu polimeryzacji. Omówiono również metody zwiększenia wydajności polimeru wielkocząsteczkowego w związku z niekorzystnym występowaniem w niektórych wypadkach znacznych równowagowych stężeń monomeru i cyklicznych oligomerów.

EN

The fundamental factors influencing polymerizability of aliphatic cyclic esters (lactones, lactides and carbonates - see Scheme A) were discussed on the basis of literature review. Thermodynamic factors (a) related mostly to the monomer ring strain and the numbers of degrees of freedom of the polymer repeating units as well as kinetic factors (b) resulting from the polymerization mechanism availability securing the sufficient polymerization rate were distinguished. An attention was paid to the fact that thermodynamically determined inability of cyclic ester to polymerize was not tantamount to its inability to ring-opening reaction. The syntheses of macromolecular copolymers containing up to 50-mole % of repeated units coming from non-homopolymerizable monomer are possible. The analysis of kinetic factors allowed concluding that there was no uniform correlation between monomer reactivity and ring size. Moreover, dependently on the polymerization mechanism, the reversed reactivity order could occur. The methods of polymer yield increasing, in connection with disadvantageous occurring (in some cases) of substantial equilibrium concentrations of monomer and cyclic oligomers were also discussed.

3

Efficient Synthesis of Macrocyclic Dilactam Crown Ethers by Fast Addition Method

Rahimzadeh M., Eshghi H., Rostami F., Faghihi Z.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 1

73-81

EN

A simple and convenient method for preparing macrocyclic dilactam crown ethers containing N2O5, N3O3, N3O4, N3O5 and N2O10 donor atoms with 18-32 membered rings was developed. These compounds were obtained in the macrocyclization step under vigorous stirring conditions as well as fast addition of reactants. This step does not require external cyclization factors such as high dilution approach, template effect or nitrogen protection and provides the expected dilactams in high yields, ranging from 65-95%. The course of the reaction is assumed to depend on the occurrence of self assembly phenomena which are stimulated by a logic concentration in a selected solvent and the yields are improved by application of high speed stirring and fast addition of reactants.

4

The Synthesis and Structure of Diaza- ans Tetraazacoronands

Lipkowski P., Urbańczyk-Lipkowska Z., Jurczak J.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 5

729-736

EN

A general method of the synthesis of simple azacoronands via the amidation reaction is presented. Several examples of the X-ray structure studies of the compounds obtained are given.