Question

1(a). Consider the compound with molecular formula C₄H₈O₂. Draw the structures of three isomers that match the following ¹H NMR information.

Isomer A: 1H singlet at 8.2 ppm, 2H triplet at 4.2 ppm, 2H sextet at 1.8 ppm, 3H triplet at 0.9 ppm

Isomer B: 2H quartet at 4.2 ppm, 3H singlet at 2.4 PPM, 3H triplet at 1.2 ppm

Isomer C: 3H singlet at 3.8 ppm, 2H quartet at 2.4 ppm, 3H triplet 1.2 ppm

(b) The mass spectrum of compound A shows molecular ion peak at m/z 88. The IR spectrum of this compound has a broad peak between 3200 and 3550 cm-1. The ¹H NMR spectrum of A shows the following peaks: a triplet at d 0.9, a singlet at d 1.1, one more singlet at d 1.15, and a quartet at d 1.6. The area ratio of these peaks is 3:6:1:2. The ¹³C NMR contains 4 signals. In the space below, propose a structure for A and justify your claim using the data provided.

Answer 1