A Simple Microwave-assisted Synthesis of Sulfonamides directly from Sulfonic Acids DE LUCA L1, GIACOMELLI G1 1Univ. of Sassari, Sassari, Italy; Background: Sulfonamides are an important class of pharmaceutical compounds with a wide spectrum of biological activities. Sulfonamides drugs have broad applications in many areas of clinical medicine, as excellent, diuretics, anticonvulsants, hypoglycemics HIV protease inhibitors, carbonic anhydrase, and caspase inhibitors and in particular as antibacterials. Methods: We wish to report here an easy and convenient technique for the preparation of sulfonamides directly from sulfonic acid or its sodium salt, improved by microwave irradiation. The method consists of the addition of 1 equiv. of TCT to a mixture of 1 equiv. of sulfonic acid and 1 equiv. of triethylamine in acetone. The reaction was carried out under microwave irradiation in a sealed tube (10-mL pressure-rated reaction vial) in a self-tuning single mode irradiating synthetizer, operating at 80 °C for 20 min. After cooling, the precipitate formed is filtered off on Celite and the solution is added with 1.2 equiv. of NaOHaq., THF and an amine. The reaction mixture is newly exposed to microwave irradiation for 10 min at 50 °C in a sealed tube and then is filtered on Celite to eliminate the formed salts, diluted with DCM and washed with water, aqueous Na2CO3, diluted HCl, and brine. The target product is obtained in pure form and in practically quantitative yield, just by concentration of the DCM extracts at reduced pressure. Results: A selection of sulfamides were synthesized from an array of sulfonic acids and the yields were satisfactory in all cases. The methodology is proficient and successful with aromatic and aliphatic sulfonic acids. The reaction is not limited to primary and secondary amines, but works well with hydrazines (entry 3) and amino acid derivatives (entry 4). Also anilines are applicable in the reaction (entry 1). entry sulfonic acid amine product yield% 1 90 2 95 3 “ 92 4 “ 80 Conclusions: The methodology described represents a convenient,handly and high yielding synthesis of sulfonamides even in large scale, as it uses mild reaction conditions and cheap and commercially available reagents.
Scheda prodotto non validato
Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo