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[摘要]：An easy and handy synthesis of sulfonamides directly from sulfonic acids or its sodium salts is reported. The reaction is performed under microwave irradn., has shown a good functional group tolerance, and is high yielding. The procedure consists of the addn. of 1 equiv of 2,4,6-trichloro-[1,3,5]-triazine to a mixt. of 1 equiv of sulfonic acid and 1 equiv of triethylamine in acetone under microwave irradn. After cooling, the ppt. formed is filtered off on Celite and the soln. is added to 1.2 equiv of aq. NaOH, THF, and an amine. The reaction mixt. is newly exposed to microwave irradn. for 10 min at 50 癈 in a sealed tube. By the addn. of a catalytic amt. of 18-crown-6 to the reaction mixt., the procedure allows the synthesis of sulfonamides directly from sulfonic acid sodium salts. |
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