Lab Section Name 3. The 1H-NMR spectrum your mono-brominated product in CD OD is
ID: 227903 • Letter: L
Question
Lab Section Name 3. The 1H-NMR spectrum your mono-brominated product in CD OD is shown below 9.0 The chemical shifts, splitting and coupling constants are as follows: 781 (d,J-25, 1 H), 7.41 (dd, J = 2.5, 8.9, l H) 6.95 (d,J-89, I H), 3.83 (s, 3H), 2.09 (s, 3H) Note: meta-coupling is observed in this spectrum. a. (3 pts) Add the substituents to complete the structure above and label with the letter of the corresponding NMR signals. (2 pts) Write a couple of short sentences to explain how you determined the position of the bromine on the molecule based on the 1-H NMR. b.Explanation / Answer
a. NMR of mono-brominated product
A : 7.81 (d, J = 2.5, 1H)
B : 7.41 (dd, J = 2.5, 8.9, 1H)
C : 6.95 (d, J = 8.9, 1H)
E : 3.83 (s, 3H)
F : 2.09 (s, 3H)
b. Bromine is an electron wihdrawing group by inductive effect, therefore, the CH proton next to Br and oxygen would be more downfield than the one next to -OCH3 alone.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.