Suggest two functional groups found in a molecule of the drug chloramphenicol.
The drug ketamine reacts readily with protons, as shown. $\text{ketamine} + \text{H}^+ \rightarrow [\text{ketamine-H}]^+$ State the function of ketamine in this reaction.
Ketamine forms an orange precipitate with 2,4-dinitrophenylhydrazine (2,4-DNPH). Suggest the functional group in the ketamine molecule that causes this observation.
The mass spectrum of ketamine has been measured. Two peaks near the molecular ion peak, M, are seen with the relative abundances shown in the table. Use the table values to demonstrate that a ketamine molecule contains 13 carbon atoms.
Besides carbon and hydrogen, each ketamine molecule contains one atom of each of three different elements; these are heteroatoms. One of them is a halogen. Use the table data to suggest which halogen this is. Explain your answer.
Another peak in the ketamine mass spectrum has an $m/e$ value of 240. Predict its relative abundance. relative abundance = ................................
Use the information in (b) to finish the molecular formula of ketamine by determining the three different heteroatoms and the number of hydrogen atoms present. $\mathrm{C_{13}H}$
Neramexane is another drug. Suggest how many peaks appear in the carbon-13 NMR spectrum of neramexane.
The proton ($^1\text{H}$) NMR spectrum of neramexane in CDCl$_3$ has five peaks with these chemical shifts ($\delta$). Complete the table.
Use the Data Booklet together with the table in (c)(ii) to finish assigning the correct $\delta$ values to each circled hydrogen atom on the neramexane structure.
One peak in the proton ($^1\text{H}$) NMR spectrum vanishes when the sample is shaken with $\text{D}_2\text{O}$. Identify which peak it is and explain the reason for its disappearance.