Free Master of Chemistry: Pharmaceutical Chemistry Questions and Answers

Question 1

In the aforementioned reaction, dichlorocarbene, a reactive intermediate, transforms phenol into 2-hydroxy benzaldehyde.

Accepted Answer

Riemer Tiemann reaction

Answer

The Reimer-Tiemann reaction is a classic organic reaction used for the ortho-formylation of phenols. It involves the reaction of a phenol with chloroform (CHCl3) in the presence of a strong base, which generates dichlorocarbene (:CCl2) as the key reactive intermediate. This intermediate then attacks the activated ortho position of the phenoxide ion, leading to the formation of 2-hydroxy benzaldehyde (salicylaldehyde from phenol).

Question 2

Which of the following chemical reactions produces 2,3-epoxyalcohols from primary and secondary allylic alcohols in an enantioselective manner?

Accepted Answer

Sharpless epoxidation

Answer

The Sharpless epoxidation is a highly enantioselective chemical reaction that converts primary and secondary allylic alcohols into 2,3-epoxyalcohols. This reaction utilizes a titanium isopropoxide catalyst, an organic hydroperoxide (typically t-butyl hydroperoxide), and a chiral diethyl tartrate ligand to achieve excellent stereocontrol, producing a specific enantiomer of the epoxide.

Question 3

In this described reaction, which is thought to take place in two phases and involves an aldehyde, a dicarbonyl, and ammonia, the dicarbonyl and ammonia first condense to produce a diimine with an unusual orientation of N-H groups:

Accepted Answer

Debus-Radziszewski imidazole synthesis

Answer

The Debus-Radziszewski imidazole synthesis is a multi-component reaction that forms imidazoles from an aldehyde, a dicarbonyl compound (like glyoxal), and ammonia. The mechanism involves initial condensation steps between the dicarbonyl and ammonia to form a diimine, followed by further reactions with the aldehyde and cyclization to yield the imidazole ring. This synthesis is known for its versatility in preparing substituted imidazoles.

Question 4

Which of the following medications has two isomers, R and S, that compete with one another to engage the enzyme binding site, inhibiting the metabolism of the other isomer?

Accepted Answer

Warfarin

Answer

Warfarin is an anticoagulant drug administered as a racemic mixture of R- and S-warfarin, which are metabolized by different cytochrome P450 enzymes. S-warfarin is significantly more potent, but both isomers can interact with enzyme binding sites and influence each other's metabolism. This competition and differential metabolism contribute to warfarin's complex pharmacokinetics and the need for careful dosage monitoring due to its narrow therapeutic index.

Question 5

Which of the following antiviral medications inhibits DNA polymerase and is an adenosine analog?

Accepted Answer

Vidarabine

Answer

Vidarabine, also known as adenine arabinoside (Ara-A), is an antiviral medication that functions as an adenosine analog. It is a purine nucleoside analog where the ribose sugar is replaced by arabinose. Vidarabine acts by inhibiting viral DNA polymerase, thereby interfering with the replication of viral DNA and consequently suppressing viral proliferation.

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Practice Test

Free Master of Chemistry: Pharmaceutical Chemistry Questions and Answers