Question

1. Provide a stepwise synthesis to carry out the following conversion. Br Br 2. Discriminate between the reactants and products by using FTIR 3. Discriminate between the reactants and products by using H-NMR 4. Discriminate between the reactants and products by using C-NMR 5. Discriminate between the reactants and products by using MS Page 1 of 1

Answer 1

1.

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2. FT-IR spectrum of the reactant gives the C-H (aromatic, bending) ~2000 cm^-1. Spectrum of product gives C-H (aromatic, bending) ~1900 cm^-1, C-Br (stretching, strong) ~ 690-500 cm^-1 , C-I (stretching, strong) ~600-500 cm^-1 while no such C-X (halogen) peak is observed in reactant.

3. H-NMR spectrum of the reactant gives only one peak corresponding to 6 Hs of benzene at 7-8 ppm. While product shows 2 peaks corresponding to 2 different hydrogens (Ha and Hb). Ha (triplet)=7.3 ppm, Hb(doublet)=7.9 ppm. (Figure attached)

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4. C-NMR of the reactant shows only one peak as all the C's are the same where as the spectrum of product shows 4 different peaks.

5. MS of the reactant gives the molecular ion peak at m/z=78 where as the product gives a molecular ion peak at m/z= 236 and other peaks at m/z= 126,80,282

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