Infrared spectra of N-aryl substituted amides 2/4-XC6H4NHCOR (R = H, CH3-iXi, C6H5 or C6H5CI; X = H, Cl or CH3 and i = 0, 1, 2 or 3)

Department of Post-Graduate Studies and Research in Chemistry, Mangalore University, Mangalagangotri-574 199, India E-mail: gowdabt@yahoo.com Fax: 91-824-2287367 Manuscript received 2 September 2002, revised 14 November 2003, accepted 10 February 2005 Several N-(aryl)-substituted amides of the general formula, 2/4-XC6H4NHCOR (where X = H, CJ or CH3, and R = H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, C6H5 or C6H5CI) are prepared, characterised and their infrared spectra measured in the solid state and analysed. Generally chloro substitution in the side chain increases the C=O absorptions, while that of methyl groups lower the wave numbers. Amides with trimethyl substituted side chains absorb at higher wavenumbers. But the N-H and C-N stretching vibrations do not show particular trends on side chain substitution. This may be due to the fact that the spectra were recorded in the solid state and the compounds may crystallise in different forms in the solid stale. The intercorrelations of C=O and N-H absorption frequencies of all the amides have been made. The correlations are reasonably linear with some exceptions for the reasons stated above