The condensation of 5-amino-1,3,4-thiadiazol-2-sulfonamide (I) with the protected guanidinoacetic acid (II) by means of EDC in acetonitrile gives the corresponding amide (III), which is then deprotected with HCl in hot dioxane.

The condensation of 5-amino-1,3,4-thiadiazol-2-sulfonamide (I) with the protected guanidinodipeptide (II) by means of EDC in acetonitrile gives the corresponding amide (III), which is then deprotected with HCl in hot dioxane.

Removal of acetyl group of acetazolamide (I) by refluxing with concentrated HCl affords 5-amino-1,3,4-thiadiazole-2-sulfonamide (II), which is then coupled to Boc-protected beta-alanine (III) by means of EDC and Et3N in acetonitrile to yield the protected derivative (IV). Finally, (IV) is treated with TFA in CH2Cl2 for Boc removal to provide the target compound. Alternatively, conversion of (II) into the desired compound can be achieved by first condensation of (II) with 3-phthalimidopropionyl chloride (V) in pyridine to give the N-phthalimido derivative (VI), which is then subjected to hydrazinolysis and finally treated with TFA.