Question

Many drugs are sold as their hydrochloric salts (R2NH2 Cl−), formed by reaction of an amine (R2NH) with HCl. a. Draw the major organic product formed from the formation of acebutolol with HCl. Acebutolol is a β blocker used to treat high blood pressure. Omit any inorganic counterions.b. Discuss the solubility of acebutlol and its hydrochloride salt in water.c. Offer a reason as to why the drug is marketed as a hydrochloride salt rather than a neutral amine.

Answer 1

Here's what I find.

Step-by-step explanation:

a. Structure

Acebutolol is a secondary amine (basic). It forms a substituted ammonium salt when treated with hydrochloric acid.

The structure of the salt is shown below, with a red arrow pointing toward the positive charge on the N atom.

b. Solubility

The formula of acebutolol is C₁₈H₂₈N₂O₄.

The amide, acetyl, and ether groups confer little solubility to the molecule.

The alcohol and secondary amine do confer some solubility, because they can donate and accept hydrogen bonds.

However, they can each overcome the hydrophobic properties of only three to five carbons, and acebutolol has 18 of them.

The free amine would be preferentially soluble in lipid material (fats)

The protonated amine is ionic and therefore much more soluble in aqueous media (e.g., blood).

c. Marketing

The drug must be delivered to the tissues of the heart, where it blocks the effects of adrenalin. The best way to do this is through the blood, so acebutolol is marketed as the hydrochloride salt.