Question

The below structure represent the drug:

• A. Isoprenaline
• B. Amphetamine
• C. Norepinephrine
• D. Salbutamol

Answer 1

The Correct Option is A

The correct option is (A): Isoprenaline.

Answer 2

The structure shown needs to be matched against four sympathomimetic amines used in pharmacology: Isoprenaline, Amphetamine, Norepinephrine, and Salbutamol. Each of these compounds differs in its ring substitution pattern and its amine side chain, so checking these two features against the drawn structure identifies the compound. Let's look at each option on its own structural merits.

1. Isoprenaline: This is a catecholamine, carrying two hydroxyl groups at the 3rd and 4th positions of the benzene ring along with a beta-hydroxyl on the ethylamine side chain. Its defining feature is a bulky isopropyl group attached to the amine nitrogen. A structure showing an intact catechol ring together with an N-isopropyl substituted ethanolamine chain matches isoprenaline exactly.
2. Amphetamine: Amphetamine is a simple phenylethylamine. It carries no hydroxyl groups on the ring at all and no beta-hydroxyl on the side chain; instead it has a methyl group on the carbon next to the amine. A structure with a plain, unsubstituted benzene ring rules this option out.
3. Norepinephrine: Like isoprenaline, norepinephrine is a catecholamine with the two ring hydroxyls and the beta-hydroxyl side chain, but its nitrogen carries only a hydrogen atom, a primary amine, not an isopropyl group. The presence of a bulky isopropyl substituent on the nitrogen in the given structure rules out norepinephrine.
4. Salbutamol: Salbutamol replaces one of the ring hydroxyls with a hydroxymethyl group at the meta position and carries a bulky tert-butyl group on the nitrogen rather than isopropyl. Because the ring in the given structure keeps both hydroxyls in the catechol pattern and the nitrogen substituent is isopropyl rather than tert-butyl, salbutamol does not fit.

Matching the catechol ring together with the N-isopropyl side chain narrows the structure down to one compound only, since the other three drugs each break at least one of these two features.

The correct answer is Isoprenaline.