New Methodology for the Synthesis of Benzoazacrown Ethers by Transformation of the Macrocycle of Benzocrown Ethers

Abstract

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Host-guest complexes of nitro-substituted N-alkylbenzoaza-18-crowns-6

“…At present, phenyl aza crown ethers are used most widely for the above purposes; however, a considerable disadvantage is that their complex formation constants with metal ions are not high. In this respect, benzo-fused aza crown ethers may be appreciably more advantageous; on the other hand, derivatives of 1-aza-2,3-benzocrown ethers have been studied fairly poorly, and most their functional derivatives are almost inaccessible despite simple structure [3,4]. We previously developed a procedure for the synthesis of N-methyl benzo aza crown compounds with different sizes of the macroring (both unsubstituted at the benzene ring and formyl-substituted) [5][6][7] and nitro-DOI: 10.1134/S1070428011070220 substituted N-alkylbenzoaza-15-crowns-5 via stepwise transformations of macroring in benzocrown ethers [8,9].…”

“…We previously developed a procedure for the synthesis of N-methyl benzo aza crown compounds with different sizes of the macroring (both unsubstituted at the benzene ring and formyl-substituted) [5][6][7] and nitro-DOI: 10.1134/S1070428011070220 substituted N-alkylbenzoaza-15-crowns-5 via stepwise transformations of macroring in benzocrown ethers [8,9]. The developed synthetic approach to functionalized aza crown ether derivatives seems to be a promising alternative to the known methods of synthesis of 1-aza-2,3-benzocrown ethers [3,4].…”

Macroring Opening in Crown Ethers. Transformation of (4′-Formylbenzo)thiacrown Ethers into Podands by the Action of Methylamine

“…The latter were used to obtain benzoazacrown ethers containing a nitrogen atom attached to the benzene ring [17][18][19][20][21] (Scheme 1). This new synthetic approach to functionalized azacrown ether derivatives from nitrogen-containing podands formed by nucleophilic cleavage of the macroring in accessible crown ethers by the action of amines seems to be a promising alternative to the existing methods of preparation of 1-aza-2,3-benzocrown ethers [22].…”