Synthesis and structural study of a series of amides derived from 4α- and 4β-amino-1-azaadamantanes as potential 5-HT3 receptor antagonists

Abstract

A series of amides derived from 4α-(2b–5b) and 4β-amino-1-azaadamantane (2a–5a) were synthesized and studied by IR, 1H, 13C, 2D NMR spectroscopy and NOE 1D experiments. The combined use of COSY, 1H–13C correlation spectra and double resonance experiments helped in the unambiguous and complete assignment of the bicyclic carbon and proton resonances. IR, 1H and 13C NMR data show the presence of an intramolecular N–H⋯O–CH3 hydrogen bond in compounds 3a and 3b. Moreover, the IR spectra of compounds 4a and 4b show a strong intermolecular hydrogen bond N–H (indole)⋯N.