Chapter 12 Multiple Choice Questions

. Which of the following structures represents the correct labelling system of tetracyclines?

Structure A

Structure B

Structure C

Structure D

. What product is formed from the catalytic hydrogenation of chlorotetracycline?

Choose from the following structures.

Product A

Product B

Product C

Product D

. The following structure shows the pharmacophore for tetracyclines. Which of the heteroatoms indicated could not act as a hydrogen bond acceptor?

Heteroatom A

Heteroatom B

Heteroatom C

Heteroatom D

. The following structure shows the pharmacophore for tetracyclines. Which of the diagrams below correctly identify the nature of the two edges?

Structure A

Structure B

Structure C

Structure D

. The following structure shows the pharmacophore for tetracyclines. Which of the rings offers the best potential for variation in order to create analogues.

Ring A

Ring B

Ring C

Ring D

. Sancycline was treated with nitric acid and sulphuric acid. Which of the following structures were the two main products?

Compounds I & II

Compounds II & III

Compounds I & III

Compounds I & IV

. 9-Aminominocycline can be converted to a series of compounds known as the glycyclcyclines using a two stage synthesis or a one stage synthesis as follows.
Two-stage process

One-stage process

Which of the following statements is incorrect?

In order to synthesise a series of analogues by the two stage process, twice as many reactions need to be carried out than if the analogues were prepared by the one-stage process

The one-stage process is more efficient than the two-stage process for the synthesis of a specific compound

A larger variety of compounds can be made more efficiently using the two stage process

Primary and secondary amines can be used in the second stage of the two-stage process, but not tertiary amines

. Minocycline is a tetracycline that has a broader range of activity than older tetracyclines, including activity against tetracycline resistant strains that are resistant because of efflux pumps. Which feature in minocycline is thought to be most important in combating resistance due to efflux pumps?

The phenol (A)

The dimethylamino group (B)

The dimethylamino group (C)

The primary amide (D)

.
What is the name given to the group of compounds having the following structure?

Fluoroamidotetracyclines

Fluorocyclines

Alkylaminomethyltetracyclines

Amidotetracyclines

. A key reactant in the full synthesis of novel tetracyclines is a tricyclic structure containing a 3-benzyloxyisoxazole ring. What is the purpose of this ring?

To increase the reactivity of the tricyclic structure for the formation of rings C and D of the tetracycline structure

To act as a steric blocker against possible side reactions on the ketone group present in ring A

To improve the solubility of the structure prior to the formation of rings C and D of the tetracyclic structure

To serve as a protecting group for the enol and primary amide groups attached to ring A of tetracylines

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