Studies on calix(aza)crowns, II. Synthesis of novel proximal doubly bridged calix[4]arenes by intramolecular ring closure of syn 1,3-and 1,2-ω-chloroalkylamides

✍ Scribed by István Bitter; Alajos Grün; Gábor Tóth; Barbara Balázs; Gyula Horváth; László Tõke

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 929 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)00112-4

✦ Synopsis

Inherently chiral calix[ljarenes (9,lO) with carboxamide bridges spanning the proximal positions on the lower rim and 18 achiral counterparts have been synthesized by double intramolecular cyclization of 7bJ3b 1.3~and 17 l,2-biwhloroalkylamides. The amfomational analysis of the 1.3-and 1,2disubstiMed calixarene intermediates S-8 and M-17 proved an equilibrium of two distorted cone conformations. The success of ring closure was strictly dependent on the chain length of the open chain precursors.