Question

Molecular Formula : Cio His NO₂ Du-5 b. Analyze three significant bands in the IR spectra below that conclude on the existing functions in the molecule. (3 points) Coo ~ 1680 cm stretching 4000 1550 oto ppm

Answer 1

IR Spectrum:

In IR spectrum mainly >C=O stretching frequecy observed at 1680 cm-1 due to amide bond.

Broad N-H stretching absorption peak observed at 3300 cm-1

absorption peak at 3000 to 3100 cm-1 observed due to alkenyl C-H streching indicates unsaturation

NMR:

(ppm) Integration multiplicity comments 3H gave triplet means 2H at adjacent carbon atom 3H gave singlet means no adjacent proton 2H gave quartet means adjacent carbon bearing 3 H and other side oxygen due to 3.9 6 value Aromatic 2H identical gave doublet means adjacent carbon bearing 2H identical Aromatic 2H identical gave doublet means adjacent carbon bearing 2H identical. Hence aromatic 1,4-disubstituted ring is present 8.0 bs Broad singlet means exchangeable-NH or-OH proton is there

Fragments:

Mol formula given is C10H13NO2 and following probable fragments are present in molecule

N-Acetyl group due to CH3 singlet peak in NMR at 2.1 ppm 1,4-dis ubstituted aromatic ring Ethoxy group

Hence final structure will be 4-Ethoxyphenyl acetamide.

4-Ethoxyphenyl acetamide