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2‐(Guanidiniocarbonyl)furans as a New Class of Potential Anion Hosts: Synthesis and First Binding Studies
Author(s) -
Schmuck Carsten,
Machon Uwe
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600324
Subject(s) - chemistry , furan , aqueous solution , decomposition , ion , combinatorial chemistry , organic chemistry , medicinal chemistry
The synthesis of a new class of potential anion hosts, the 2‐(guanidiniocarbonyl)furans 5a – d , is presented in this study. The facile decomposition of furans under acidic conditions makes the synthesis of these compounds challenging. First binding studies showed that the (guanidiniocarbonyl)furans are much more acidic (p K a ≈ 5.5) than the analogous pyrroles (p K a ≈ 7) previously introduced by us for oxoanion binding in aqueous solvents. Hence, anion binding with the furan derivatives occurs only in acidic solutions below pH = 5. Therefore, carboxylates are not bound efficiently, whereas, for example, the less basic hydrogen sulfate is bound by 5b with an association constant of K = 600 M –1 in aqueous DMSO even in the presence of a large excess of buffer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)