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The purification of p-acetaminobenzenesulfonyl chloride
8IO
BIOCHEMICAL RESEARCH FOUNDATION.
[J. F. I.
the stability of the boundaries, it might be demonstrated with certain oxidizing enzymes in the absence of their coenzymes, because combination between enzyme and substrate would not be followed by reaction. In answer to the suggestion by Mr. T h o m a s Dietz t h a t it might be preferable to carry out electrophoretic experiments with undiluted, rather t h a n diluted, serum, the s t a t e m e n t was made t h a t dilution of serum has not been found to cause changes in electrophoretic behavior, though it does cause changes in particle size which have been detected by means of the ultracentrifuge. W h e n whole serum is allowed to migrate into 9/IO diluted serum, the same constituents are observed as in I/IO diluted serum, and in the same concentrations. Although in ultracentrifuge measurements with slightly diluted serum it has been observed t h a t the substitution of phosphate buffer for Ringer solution causes further dissociation of the X (or beta globulin) fraction, the removal of electrolytes from serum by dialysis against p h o s p h a t e buffer has not been found to influence materially the electrophoretic pattern, though small changes m a y possibly occur. Concerning the stability of serum on standing, it was stated t h a t frozen serum can be stored for some time without alteration of behavior in electrophoresis and sedimentation. (Reported by Laura E. Krejci.)
The Purification of p-Acetaminobenzenesulfonyl Chloride. - - L . H. PENCE AND H. C. WINTER (Journal of the American Chemical Society 6x, 2977 (I939)). The discovery of the therapeutic value of sulfanilamide in the t r e a t m e n t of bacterial infections has given impetus to the investigation of a great n u m b e r of compounds related to it. The i m p o r t a n t intermediate used in the synthesis of these compounds is p-acetaminobenzenesulfonyl chloride, which reacts with various amines to give the corresponding sulfanilamide derivatives. Investigators in this field, however, have been inconvenienced because of the lack of a suitable m e t h o d for purifying large quantities of the sulfonyl chloride. It is essential t h a t the intermediate be purified immediately after its preparation, since the c o m p o u n d readily decomposes when it is allowed to stand in the crude state. The least satisfac-
Dec., I939.]
BIOCIIEMICAL t~ESEARCH FOUNDATION.
81 I
tory part of its preparation, unfortunately, has been the purification. This was a distinct disadvantage when storage of appreciable a m o u n t s of the intermediate for future use was desired. A convenient m e t h o d for purifying large quantities of the acid chloride is therefore a welcome improvement. Smiles and Stewart (Organic Syntheses, V, 3 (1925)) used benzene as the solvent for the recrystallization of the 9 ° g. of crude sulfonyl chloride obtained by their procedure. Since the product will dissolve in benzene only to the extent of 2 per cent. when hot and 0.5 per cent. cold, giving a 70 g. yield of pure p-acetaminobenzenesulfonyl chloride, they have stated that the recrystallization of more than a small a m o u n t of the compound at one time is not practical. In the present paper a new modification is given which is an i m p r o v e m e n t over the former method for the purification of large a m o u n t s of the sulfonyl chloride from the standpoints of both time and convenience. After starting with the quantities and procedure suggested by Smiles and Stewart (acetanilide (67. 5 g.) and chlorosulfonic acid (290 g.)), the crude, precipitated p-acetaminobenzenesulfonyl chloride is obtained on pouring the reaction mixture into crushed ice. The crude solid is separated by centrifuging and washed three times with water. The d a m p precipitate is dissolved in ether (IOOO cc.), and the latter washed in a separatory funnel with four 50 cc. portions of water. The last portion of wash water is then free of sulfate ion. After drying the ethereal solution for one hour over anhydrous sodium sulfate the drying agent is removed by filtration. Longer drying is to be avoided to prevent the precipitation of the sulfonyl chloride, since the latter is less soluble in dried ether. The ethereal solution is concentrated to 300 cc., at which point the acid chloride begins to crystallize out, and benzene (Iooo cc.) is added. After cooling to o °, the crystals are filtered off by suction, washed with benzene, and dried in vacuo. The average yield of several preparations of the colorless crystals of p-acetaminobenzenesulfonyl chloride was 7 ° g., melting at I49 °. The melting point of an earlier preparation (m.p. I48°) remained unchanged after the compound stood for seven months.
BIOCHEMICAL RESEARCH FOUNDATION.
[J. F. I.
the stability of the boundaries, it might be demonstrated with certain oxidizing enzymes in the absence of their coenzymes, because combination between enzyme and substrate would not be followed by reaction. In answer to the suggestion by Mr. T h o m a s Dietz t h a t it might be preferable to carry out electrophoretic experiments with undiluted, rather t h a n diluted, serum, the s t a t e m e n t was made t h a t dilution of serum has not been found to cause changes in electrophoretic behavior, though it does cause changes in particle size which have been detected by means of the ultracentrifuge. W h e n whole serum is allowed to migrate into 9/IO diluted serum, the same constituents are observed as in I/IO diluted serum, and in the same concentrations. Although in ultracentrifuge measurements with slightly diluted serum it has been observed t h a t the substitution of phosphate buffer for Ringer solution causes further dissociation of the X (or beta globulin) fraction, the removal of electrolytes from serum by dialysis against p h o s p h a t e buffer has not been found to influence materially the electrophoretic pattern, though small changes m a y possibly occur. Concerning the stability of serum on standing, it was stated t h a t frozen serum can be stored for some time without alteration of behavior in electrophoresis and sedimentation. (Reported by Laura E. Krejci.)
The Purification of p-Acetaminobenzenesulfonyl Chloride. - - L . H. PENCE AND H. C. WINTER (Journal of the American Chemical Society 6x, 2977 (I939)). The discovery of the therapeutic value of sulfanilamide in the t r e a t m e n t of bacterial infections has given impetus to the investigation of a great n u m b e r of compounds related to it. The i m p o r t a n t intermediate used in the synthesis of these compounds is p-acetaminobenzenesulfonyl chloride, which reacts with various amines to give the corresponding sulfanilamide derivatives. Investigators in this field, however, have been inconvenienced because of the lack of a suitable m e t h o d for purifying large quantities of the sulfonyl chloride. It is essential t h a t the intermediate be purified immediately after its preparation, since the c o m p o u n d readily decomposes when it is allowed to stand in the crude state. The least satisfac-
Dec., I939.]
BIOCIIEMICAL t~ESEARCH FOUNDATION.
81 I
tory part of its preparation, unfortunately, has been the purification. This was a distinct disadvantage when storage of appreciable a m o u n t s of the intermediate for future use was desired. A convenient m e t h o d for purifying large quantities of the acid chloride is therefore a welcome improvement. Smiles and Stewart (Organic Syntheses, V, 3 (1925)) used benzene as the solvent for the recrystallization of the 9 ° g. of crude sulfonyl chloride obtained by their procedure. Since the product will dissolve in benzene only to the extent of 2 per cent. when hot and 0.5 per cent. cold, giving a 70 g. yield of pure p-acetaminobenzenesulfonyl chloride, they have stated that the recrystallization of more than a small a m o u n t of the compound at one time is not practical. In the present paper a new modification is given which is an i m p r o v e m e n t over the former method for the purification of large a m o u n t s of the sulfonyl chloride from the standpoints of both time and convenience. After starting with the quantities and procedure suggested by Smiles and Stewart (acetanilide (67. 5 g.) and chlorosulfonic acid (290 g.)), the crude, precipitated p-acetaminobenzenesulfonyl chloride is obtained on pouring the reaction mixture into crushed ice. The crude solid is separated by centrifuging and washed three times with water. The d a m p precipitate is dissolved in ether (IOOO cc.), and the latter washed in a separatory funnel with four 50 cc. portions of water. The last portion of wash water is then free of sulfate ion. After drying the ethereal solution for one hour over anhydrous sodium sulfate the drying agent is removed by filtration. Longer drying is to be avoided to prevent the precipitation of the sulfonyl chloride, since the latter is less soluble in dried ether. The ethereal solution is concentrated to 300 cc., at which point the acid chloride begins to crystallize out, and benzene (Iooo cc.) is added. After cooling to o °, the crystals are filtered off by suction, washed with benzene, and dried in vacuo. The average yield of several preparations of the colorless crystals of p-acetaminobenzenesulfonyl chloride was 7 ° g., melting at I49 °. The melting point of an earlier preparation (m.p. I48°) remained unchanged after the compound stood for seven months.