Organic Lab Reactions 144

Organic Lab Reactions 144 - bottomed flask with the aid of...

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WITH THIONYL CHLORIDE 139 arm is placed 25 cc. of dry ether containing 2 drops of pyridine. To the cooled mixture are added 8 cc. (about 0.1 mole) of commercial thionyl chloride and then^l3 g. (0.06 mole) of 7-l-naphthylbutyric acid. The flask is stoppered and allowed to stand in the hood at room temperature for one-half hour with occasional swirling. A piece of porous plate is introduced, and the mixture is warmed for ten minutes on the steam bath in order to complete the reaction. The drying tube is then removed and suction (water pump) gradually applied to remove all the ether and excess thionyl chloride. The. temperature should not be permitted to exceed 40°. After a few minutes at the full pressure of the water pump about 5 cc. of dry benzene is added and the process repeated. The last traces of volatile substances may be removed by reducing the pressure to about 1 mm. with the vacuum pump for about five minutes. The acid chloride, which remains as an oil, is transferred into a 200-cc. round-
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Unformatted text preview: bottomed flask with the aid of 60 cc. of dry, thiophene-free benzene. As in Procedure I the mixture is chilled, 15 cc. (0.13 mole) of stannic chloride in 15 cc. of benzene is added, and after being swirled for five to ten minutes at 5° the mixture is hydrolyzed (using 50 cc. of concentrated hydrochloric acid) and worked up as in Procedure I. It is advisable to distil (a two-bulb type flask 96 is satisfactory) the crude ketone under reduced pressure (1-2 mm.) before recrystallizing from methanol. The yield of material m.p. 94-96° is 11.0-11.2 g. (92-94%). A list of ketones which have been prepared by the Friedel-Crafts stannic chloride method may be found in Table VI. Yields marked by an asterisk were obtained from acid chlorides prepared by the phos-phorus pentachloride procedure; all others were obtained from acid chlorides prepared from thionyl chloride. •* Fieser, "Experiments in Organic Chemistry," 2nd ed., pp. 250 and 318, D. C. Heath and Co., 1941....
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