Question

Which among the following drugs on standing in aqueous solution can dimerize to 2,5- bis(aminoxy-methyl) 3,6-diketopiperazine?

• A. Pyrazinamide
• B. Ethionamide
• C. Diethylcarbamazine
• D. Cycloserine

Answer 1

The Correct Option is D

To determine which drug dimerizes to form 2,5-bis(aminoxy-methyl) 3,6-diketopiperazine when standing in an aqueous solution, we need to analyze the chemical properties and reactive behavior of the given drugs.

1. Pyrazinamide: Pyrazinamide is primarily used as an antimycobacterial agent in the treatment of tuberculosis. It lacks the structural characteristics necessary for spontaneous dimerization into a diketopiperazine.
2. Ethionamide: This is another antibiotic used for tuberculosis, but it also does not have the chemical structure that commonly leads to dimerization into a diketopiperazine.
3. Diethylcarbamazine: Diethylcarbamazine is an anthelmintic drug used to treat filariasis. Similarly, it does not possess a molecular structure conducive to the formation of diketopiperazines through dimerization.
4. Cycloserine: Cycloserine is an antibiotic that has the propensity to dimerize in aqueous solution to form 2,5-bis(aminoxy-methyl) 3,6-diketopiperazine. This is possible because cycloserine contains both an acyclic amide and an aminooxy functionality, which can lead to the formation of a diketopiperazine ring structure upon standing in solution.

By evaluating each option, it's clear that Cycloserine is the only drug capable of forming the described dimerization product. This is due to its ability to undergo intramolecular reactions, transforming into a diketopiperazine, which is a known behavior in medicinal chemistry.

Therefore, the correct answer is Cycloserine.