?

Organic Chemistry 1

Free Version

Upgrade subject to access all content

Moderate

Ephedrine: $^1$HNMR of Hydroxyl and Amino Groups

ORGO1-DKSSTT

Shown below is the $^1$HNMR (1R, 2S)-ephedrine spectrum in ${D}_{2}O$. Maleic acid was added as an internal standard. The structure of maleic acid is shown on the bottom left, while that of (1R, 2S)-ephedrine is shown on the bottom right. Hydrogens are labeled with lower case letters.

Point out the signal from the hydroxyl proton (${H}_{f}$) and the amino proton (${H}_{c}$) in the given spectrum, respectively.

$^1H$NMR of (1R, 2S)-Ephedrine. Created for Albert.io. Copyright 2016. All rights reserved.

A

Hydroxyl proton (${H}_{f}$): doublet at 5.14 ppm.
Amino proton (${H}_{c}$): doublet at 1.14 ppm.

B

Hydroxyl proton (${H}_{f}$): doublet at 5.14 ppm.
Amino proton (${H}_{c}$): multiplet at 3.56 ppm.

C

Hydroxyl proton (${H}_{f}$): doublet at 3.56 ppm.
Amino proton (${H}_{c}$): doublet at 1.14 ppm.

D

Their signals are missing.