Directed molecular recognition: design and synthesis of neutral receptors for biotin to bind both its functional groups.

The neutral receptors 1 and 2 are designed and synthesized for the recognition of biotin, a biologically significant molecule, in chloroform to bind completely both of its functional groups simultaneously, i.e., cyclic urea and the carboxyl groups. The truncated receptor 3 binds only the cyclic urea moiety.