Azacrown ether synthesis

Several methods have been developed for azacrown ether synthesis. The most obvious approach was to allow a bifunctional polyether, such as a diiodide, react with an amine. Calverly and Dale used this method to prepare... 

The preparation of novel triazole-containing 20-22 membered macrocyclic azacrown ether-thioethers was reported <96JCR(S)182> and the first selective synthetic method fra the synthesis of dicyanotriazolehemiporhyrazines was published <96JOC6446>. 1,2,4-Triazole-containing polyimide beads were prepared and employed as Mo(VI) epoxidation catalyst supports, liie 1,2,4-nitronyl nitroxide 29 was also synthesized and found to have remarkable magnetic properties <96AM60>. 

Ring-opening with heteroatomic nucleophiles is certainly among the most thoroughly studied behavior of epoxides, and this reaction continues to be a versatile workhorse of synthetic utility. This is exemplified in the recent literature by the examples of the p-cyclodextrin-catalyzed aminolysis of simple epoxides by aniline derivatives (i.e., 53 - 54) <00SL339> and the synthesis of oxa-azacrown ethers through the treatment of Ws-epoxides 55 with diamines 56. Yields in the latter synthesis are sensitive to the size of the macrocycle and substitution on the bis-epoxide <00TL1019>. 

P. Bako, K. Vizvardi, S. Toppet, E. V. der Eycken, G. J. Hoonaert, L. Toke, Synthesis, Extraction Ability and Application in Asymmetric Synthesis of Azacrown Ethers derived from D-Glucose , Tetrahedron 1998, 54, 14975-14988. 

Synthesis of the azacrown ether-t)fpe quaternary ammonium salt. 232... 

SYNTHESIS OF THE AZACROWN ETHER-TYPE QUATERNARY AMMONIUM SALT... 

Fedorova, O.A., Gromov, S.P., Pershina, Y.V., Sergeev, S.S., Strokach, Y.P., Barachevsky, V.A., Alfimov, M.V., Pepe, G., Samat, A., Guglielmetti, R. (2000) Novel azacrown ether-containing spiro[indoline-2,3,-naphthoxazines] design, synthesis and cation-dependent photochromism, J. Chem. Soc., Perkin Trans. 2, 563-571. 

The synthesis and use of 7,16-(di-4-pyridinyl)-l,4,10,13-tetraoxa-7,16-diazacyclo-octadecane, prepared from the commercially available azacrown ether and 4-bromopyridine,... 

Although the synthesis and host-guest chemistry of azacrown ethers is well developed their exploitation as molecular catalysts has been comparatively scarce. A... 

Figure 7 Azacrown ethers (a) aza-12-crown-4 synthesis (b) an early azacrown lariat ethCT (c) a convenient route to...

Two routes are available to prepare IV-functionalized azacrowns addition of the side arm to the nitrogen of an appropriately sized azacrown, or reaction of the side arm with diethanolamine followed by azacrown ether formation through templated synthesis with the appropriate ditosyl-or diiodopolyether. The former route is preferred when researchers want to attach a range of side arms to the same sized crown and the latter is preferred when the same side arm is to be introduced to crowns of different sizes. These routes are shown in Figure 16. 

The synthesis of azacrown ether 33 utilized the templating effect of added dibenzylammonium ion in the condensation of 4-alkoxy-substituted... 

A template synthesis for the bicyclic azacrown ether L1485 (a cryptand, see Section 4.1) is given in Scheme 6-7 [166]. 

The synthesis of a variety of alkyl substituted (both at carbon and nitrogen) crown and azacrown ethers were reported and found to be efficient catalysts for... 

The synthetic versatility of azacrowns (crown ethers with some oxygen atoms replaced with NH functionalities), such as 3.18, has made possible the synthesis of an enormous range of... 

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