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Unformatted text preview: 354 PRACTICAL ORGANIC CHEMISTRY chloride, precisely as described for carboxylic acids (p. 349), gives the benzylthiouronium salt, usually of sharp m.p. Many of these salts can be recrystallised readily from water, and are the most rapidly prepared derivatives. (M.ps., p. 548.) (B) Sulphonamides. Mix 0-5 g. of the sulphomc acid or its alkali salt with 1-5 g. of phosphorus pentachloride, and heat under reflux in a silicone- or oil-bath at 150° for 30 minutes; then allow it to cool. (i) To prepare the sulphonamide, add 10 ml. of concentrated ( d , 0-880) ammonia cautiously down the condenser, shaking the mixture meanwhile. Then detach and securely cork the flask, and shake it vigorously for several minutes. If a large lump of material forms, break it up carefully with a thick glass rod, and shake the mixture again. Filter off the solid product at the pump, wash it with water, and drain well. Then recrystallise preferably from boiling water, or if necessary from aqueous ethanol, filtering the hot solution. Filter off the crystallineethanol, filtering the hot solution....
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.
- Fall '06
- Organic chemistry