SAR of Loop Diuretics

SAR of Loop Diuretics

They are either 5-sulphamoyl-2-amino benzoic acid or 5-sulphamoyl-3-amino benzoic acid derivatives.

1. The carbonyl group at C-1 provides optimal diuretic activity.

2. The substitution of activating group (X) in the position 4 by Cl, alkoxy, aniline, benzyl, or benzoyl group at 4th position increases the diuretic activity.

3. The presence of sulphamoyl group in the 5th position is essential for activity.

4. The two series of 5-sulphamoyl benzoic acid differ in the nature of the functional group that substituted in 2nd and 3rd position.

5. The presence of furfuryl, phenyl, and thienyl methyl group at 2nd amino group of 5-sulphomoyl-2-amino benzoic acid gives maximum diuretic activity.

6. The wide range of alkyl group can be substituted at 3rd amino group of 5-sulfamoyl-3-amino benzoic acid without modifying the optimal diuretic activity.

7. A molecule with a weakly acidic group to direct the drug to the kidney and an alkylating moiety to react with sulphydryl groups and lipophilic groups seemed to provide the best combination of a diuretic in the class.

i. 5-Sulphamoyl-2-amino benzoic acid derivatives

ii. 5-Sulphamoyl-3-amino benzoic acid derivatives