Question

Use the proton NMR and carbon 13 resonances to identify the two different isomers of the molecule with the formula: C5O2H10

These two isomers are different! Do not draw the same structure for both!

1) draw the isomer and label the proton NMR that corresponds with the structure proposed.

2) draw the second isomer and label the proton NMR that corresponds with the structure proposed.

atosIII your structureS 1.13C Resonances 200.7,88.3,56.6 20.0, and 7.7 3.24 3H,s 0.96 9.72 3.70 H.A -7 1.79 2H,ant JR7 6 PPM 2.13C Resonances 204.1,76.0, 59.3 45.3, and 10.3 3.24 3.54 Hdd 1.17 3.79-27 H.dd 9.72 J-12,7 2.85 1H,sep J-7 PPM

Answer 1

Interpretation of NMR

1. 1H NMR

1.0 ppm (3H) for CH3 next to CH2

1.8 ppm (CH2) for CH2 between CH and CH3

3.2 ppm (3H) for CH3 next to Oxygen

3.7 ppm (1H) for CH between OCH3 and CHO

9.7 ppm (1H) for aldehydic proton

2. 1H NMR

1.2 ppm (3H) for CH3 next to CH

2.8 ppm (1H) CH next to CHO

3.2 ppm (3H) for CH3 next to oxygen

3.5 ppm (1H) and 3.7 ppm (1H) for CH2 protons which are heterotopic.

9.7 ppm for aldehydic proton

The structures are drawn below

CHO OCH 3 compound 1 CHO OCH3 compound 2