Question

Index the spectrum of methyl 3-nitrobenzoate provided (taken on a 300 MHz spectrometer in  CDCl­₃).  Assign the different protons of the compound to the NMR signals.

H NMR of Methyl 3-Nitrobenzoate (Expanded) 8.874 8.867 8.861 8.441 8.437 8.433 8.430 8.414 8.410 一8.406 8.402 8.391 -8 . 386 8.382 8.365 8.361 8.356 1.816

Answer 1

Structure of methyl-3-nitrobenzoate is: Thus it has two types of Protons methyl (CH_3) proton and Four aromatic protons but they appear at different due to non equivalent nature due to different substituent at meta position. There detailed explanation given below: Ha: due to both carbonyl and NO_2 group are electron with drawing in nature Ha appear at more downfield position and also due to meta-coupling it gives triplet at 8.867 ppm Hb: It gives quartet due to coupling with one Ortho and two meta coupling & may occurs at delta 8.41 ppm Hc: [It gives triplet due to two Ortho proton (2 + 1) = 3] and may occurs at delta - 8.35 ppm Hd: It also gives quartet due to two meta and one Ortho proton & benzene ring and It may occurs more down field delta at 8.40 ppm \r\n He: It os methyl (CH_3) Proton gives singlet delta at 4.00 ppm - due to oxygen they are also .