A convenient synthetic method for N-acylation of sulfonamides in the presence of P 2 O 5 /SiO 2 is described. Carboxylic acid anhydrides and carboxylic acid chlorides were used as acylating agents and the reactions were carried out in CH 2 Cl 2 or solventfree conditions. The catalyst can be recovered by simple filtration and can be used in the subsequent reactions.

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Sulfonamides Q 0560Facile Synthesis of N-Acylsulfonamide in the Presence of Silica Chloride (SiO 2 -Cl) Both under Heterogeneous and Solvent-Free Conditions. -Simple methods for the effective N-acylation of sulfonamides using carboxylic acid anhydrides or chlorides are developed. The solvent-free N-acylation, that proceeds somewhat faster than the corresponding reaction in solution, is a green approach to the preparation of N-acylsulfonamides (III). -(MASSAH*, A. R.; MOMENI, A. R.; DABAGH, M.; ALIYAN, H.; NAGHASH, H. J.; Synth. Commun. 38 (2008) 2, 265-273; Dep. Chem., Shahreza Islamic Azad Univ., Isfahan 86145, Iran; Eng.) -H. Toeppel 25-092