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Novel Bis‐betaines and Betaines within [1 4 ] meta ‐Heterophane Frameworks
Author(s) -
Alcalde Ermitas,
Mesquida Neus,
PérezGarcía Lluïsa,
Ramos Susana,
Alemany Montserrat,
Rodríguez Matías L.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020118)8:2<474::aid-chem474>3.0.co;2-9
Subject(s) - betaine , electrospray ionization , chemistry , electrophile , crystallography , mass spectrometry , reactivity (psychology) , crystal structure , stereochemistry , organic chemistry , medicine , alternative medicine , chromatography , pathology , catalysis
After prior selection of betaine building blocks for the construction of quadrupolar heterophane frameworks, a convergent “3+1” synthetic strategy is reported for the synthesis of the title macrocycles composed of heterocyclic betaine subunit(s). These typify the first example of simple cyclophanes constructed out of both highly π‐excessive and highly π‐deficient heteroaromatic moieties linked in a 1,3‐alternating fashion. The chemical reactivity of the quadrupolar heterophanes 1 a and 1 c toward electrophiles under neutral conditions corroborated their bis‐betaine structure. The structural features of the bis‐betaines 1 , betaines 2⋅ PF 6 and 5⋅ X, and the corresponding dicationic [1 4 ]heterophanes 3⋅ 2 X and 4⋅ 2 Cl were studied by 1 H and 13 C NMR spectroscopy and electrospray ionization mass spectrometry, and confirmed by single‐crystal X‐ray diffraction analysis of macrocycles 1 a and 2 a⋅ PF 6 .