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
- The compound 4-nitrophenol shown contains all of the following signals in its infrared spectrum EXCEPT:

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
-

The compound 4-nitrophenol shown contains all of the following signals in its infrared spectrum EXCEPT:

Quizplus · Accepted Answer

11ecba2d_1257_c7c6_a3bf_65172a74d2db_MD0008_00 In infrared (IR) spectroscopy, a sample is irradiated with IR light, and a spectrometer detects and records the percentage of radiation that passes through the sample over a range of frequencies. The IR spectrum of a compound indicates the types of bonds and functional groups present in a compound. Different functional groups absorb IR radiation at different frequencies, and therefore the signal from each group appears in a particular region of the IR spectrum. Although individual molecules may have distinct absorption spectra in the fingerprint region (700-1500 cm⁻¹), each functional group on the molecule will still absorb in its characteristic IR region regardless of the global structural features of the molecule. The compound 4-nitrophenol contains the following functional groups: Hydroxyl group (-OH) Aromatic ring Nitro group (-NO₂) However, 4-nitrophenol does not contain any N-H bonds, and therefore would NOT contain an N-H stretch. (Choice A) A hydroxyl group is present, providing an O-H stretch in the IR spectrum. (Choice B) An aromatic ring is present, providing a C=C stretch in the IR spectrum. (Choice C) A nitro group is present, providing an N-O stretch in the IR spectrum. Educational objective: An infrared (IR) spectrum displays absorption signals characteristic of the functional groups in a particular molecule based on the IR frequencies absorbed by those functional groups. Functional group bands appear in the same region of the IR spectrum regardless of the overall structure of the molecule.

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