Question

2. The following 'H NMR spectrum (300 MHz) belongs to a naturally occurring amino acid tyrosine. This spectrum was taken in D,O with DCI added. The amino, carboxyl, and hydroxyl protons merge into a signle peak at 5.1 ppm. Assign all peaks, and account for the coupling patterns for each.

Answer 1

Angwer: The chemical structure OH u chuire de Он In polar solvent like Do the polar protons of yoosine egin -OH, -NH, ond -COOH exchange with deuterium (8) hence with be absent in TH NMR spectra (ii) The chemical signal arand 3.2-3.4 ppo correspond to the side chain diastered topic protons (protons nenot to Chircul centre). They appears as doublet of doublet - because of Coupling with each other and with a- proton. om O 32 - 34 pm 20H wrdu Poit correspond (11) 7.0 -7.3ppm The chemical signal around - to the 4 aromatic protons. Coupling of ' with ' ' Cho'rs. - result in doublet of і діама. (i%) The chemical signal around 4.4 ppm correspond to the d-H proton which couple with a side chain protons and appears as triplet. 30 + 4.4 ppm u