polymer particles the rate of polymerization of styrene is proportional to the number of polymer particles present and is in dependent of the persulfate concentration. This can best be interpreted as indicating that the average number of free

During studies (1) on the Beckmann rearrangement of the oximes of 2-benzoylpyridine, necessity arose for the characterization of 2-(benzoylamino)pyridine. Although this compound has been previously reported by five different laboratories, the record disclosed a distressing lack of accord.2-(Benzoylamino)pyridine was first reported (2) from 2-aminopyridine by reaction with benzoyl chloride and aqueous alkali and next (3) by reaction with benzoic anhydride. The compound was claimed to melt at 165°( 2, 3), to form a picrate salt, m.p. 146°( 2) and both the supposed benzoyl derivative and its salt gave, respectively, appropriate analyses (2). Despite the concordance of these results both reports were completely erroneous.Subsequent studies by Tschitschibabin and Bylinkin (4), completely confirmed by Wibaut and Dingemanse (5), utilized both methods but obtained 2-(benzoylamino)pyridine of m.p. 87°and 2-(dibenzoylamino)pyridine of m.p. 166-167°.The latter was readily hydrolyzed with dilute sodium carbonate to the former.This apparent resolution of the earlier errors was soon complicated by a German patent (6) which claimed that 2-aminopyridine with benzoic anhydride gave 2-(dibenzoylamino)pyridine, m.p. 94-95°, and by a report (7) that earbodi-(2pyridyl)imide with benzoic acid gave 2-(benzoylamino)pyridine, m.p. 80°. Still later 2-aminopyridinium benzoate was reported (8) as melting 145-146°.By Schotten-Baumann benzoylation of 2-aminopyridine we have obtained 2-(dibenzoylamino)pyridine, m.p. 167.5-169°u ncor., confirming the Russian (4)and Dutch (5) reports. Hydrolysis with alcoholic sodium carbonate yielded 2-(benzoylamino)pyridine as earlier reported (4) but this product melted sharply at 82-83°u ncor., and no higher value has ever been obtained for it in our work. This same 2-(benzoylamino)pyridine was also obtained (1) by Beckmann rearrangement of syn-phenyl 2-pyridyl ketoxime using thionyl chloride. Contrary to the earlier reports (3, 4, 5), the reaction of 2-aminopyridine with benzoic anhydride gave in our hands 2-aminopyridinium benzoate, m.p. 145-146°u ncor.[recorded (8) 145-146°], and the benzoate salt of 2-(benzoyIamino)pyridine, m.p. 93.5-94.5°p reviously described (6) as 2-(dibenzoylammo)pyridine.Both these salts titrated sharply with alkali, giving appropriate neutralization equivalents, while the true 2-(dibenzoylamino)pyridine did not titrate with alkali at all. The identity of the 2-(benzoylamino)pyridinium benzoate, m.p. 93.5-94.5°was further confirmed by isolation of both components and by repreparation from them. SUMMARY 1. Benzoylation of 2-aminopyridine by the Schotten-Baumann method gives in excellent yield 2-(dibenzoylamino)pyridine.

The fermentation was carried out in a 400-liter resinlined tank using the synthetic medium described by Stone and Farrell1 and culture Q-176 of Penicillium notatum. The precursor, -chlorocrotylmercaptoacetic acid, was employed at a concentration of 250 mg. per liter. The assay of the beer at harvest (sixty-four hours) was 250 Oxford Units per ml. When processed by the carbon-acetone method,2 44 g. of crude sodium salt was obtained; bioassay, 625 Oxford units per mg.; purity indicated by hydroxylamine assay,3 24%. The crude penicillin was purified by partition chromatography*•6•6 of the free acid on an ether-silica column using pH 6.2 potassium phosphate buffer. A peak fraction in the eluates7 which included 70% of the activity was titrated to pH 7.0 with 1% potassium hydroxide solution and dried from the frozen state. The resulting amorphous potassium salt crystallized when treated with dry acetone. It was recrystallized by dissolving it in 90% acetone and adding 3 volumes of dry acetone. The yield of recrystallized potassium salt was 4.2 g.; bio-assay, 1900 Oxford units per mg.