Passage
The drug paracetamol, also known as acetaminophen, is used to relieve pain and fever, and is a metabolite of the antipyretic drug phenacetin (Figure 1) . These two drugs have similar medicinal properties, but phenacetin has been shown to be carcinogenic and cause kidney damage. Acetaminophen is a safer alternative to phenacetin when taken in therapeutic doses.
Figure 1 Structure of phenacetinA student synthesizes acetaminophen in a laboratory from phenol according to the reactions shown. The synthesis begins with the nitration of phenol by sodium nitrate (NaNO₃) to produce the mixture of the isomers 2-nitrophenol and 4-nitrophenol (Reaction 1) . These isomers can be easily separated by steam distillation to isolate the desired product, 4-nitrophenol. Reduction of the nitro group with sodium borohydride (NaBH₄) (Reaction 2) is followed by acetylation of the amine with acetic anhydride (Reaction 3) to afford the final product, acetaminophen.
Reaction 1
Reaction 2
Reaction 3
-Which technique could monitor the formation of 4-aminophenol by excitation of electrons with high-energy photons?

Question

Passage
The drug paracetamol, also known as acetaminophen, is used to relieve pain and fever, and is a metabolite of the antipyretic drug phenacetin (Figure 1) . These two drugs have similar medicinal properties, but phenacetin has been shown to be carcinogenic and cause kidney damage. Acetaminophen is a safer alternative to phenacetin when taken in therapeutic doses.

Figure 1 Structure of phenacetinA student synthesizes acetaminophen in a laboratory from phenol according to the reactions shown. The synthesis begins with the nitration of phenol by sodium nitrate (NaNO₃) to produce the mixture of the isomers 2-nitrophenol and 4-nitrophenol (Reaction 1) . These isomers can be easily separated by steam distillation to isolate the desired product, 4-nitrophenol. Reduction of the nitro group with sodium borohydride (NaBH₄) (Reaction 2) is followed by acetylation of the amine with acetic anhydride (Reaction 3) to afford the final product, acetaminophen.

Reaction 1

Reaction 2

Reaction 3
-Which technique could monitor the formation of 4-aminophenol by excitation of electrons with high-energy photons?

Quizplus · Accepted Answer

11ecba2d_1259_2759_a3bf_59bc23385fee_MD0008_00 Thin layer chromatography (TLC) is a useful technique to monitor reactions. Ultraviolet (UV) light can be used to visualize the results from TLC if the components from the reaction mixture can absorb UV light. UV light carries a large amount of energy that can excite the electrons of UV chromophores to a higher energy state. UV chromophores include double and triple bonds, carbonyls (C=O), nitroso groups, alkyl halides, and conjugated systems. The aromatic ring in both the starting material of the reaction (4-nitrophenol) and the product (4-aminophenol) is a UV chromophore, so each compound can absorb UV light and will appear on the TLC plate. (Choice A) In mass spectrometry, a sample is ionized by high-energy electrons, but the electrons do not change energy levels. (Choice B) An external magnetic field is applied to a sample in NMR spectroscopy. Radio waves, which are low in energy, are used to detect hydrogen atoms and excite them from the α spin to the β spin state. (Choice D) Gas chromatography requires vaporization of a sample, which is a phase change and not an electronic excitation. Educational objective: Absorption of ultraviolet (UV) light induces electron excitation, and a compound must contain a UV chromophore to absorb UV light.

Passage the Drug Paracetamol, Also Known as Acetaminophen, Is Used to to Relieve