Synthesis and FTIR spectroscopic study of some N-monosubstituted propanamides

In the present work we investigated the conformations of some N-mono-substituted propanamides of general formula CH3CH2CONHR, wherein R is chosen from n-(C-1-C-9)alkyl, cyclo(C-3-C-6)alkyl, some branched (C-3-C-6)alkyl or phenyl. The amides were synthesised by the well known Schotten-Baumann reaction-acylation of the corresponding amines with propionyl chloride. On the basis of FTIR data for diluted solutions (concentrations below 10(-3) mol dm(-3)) of N-mono-substituted propanamides in carbon tetrachloride, chloroform, dichloromethane, or a 1:1.5 mixture of benzene and carbon tetrachloride the exact position of the N-H stretching band was established. For spectroscopic data the different conformational isomers were assigned and its structures unequivocally proven. These results are in good accordance with H-1 NMR and MS data. (C) 1997 Elsevier Science B.V.