NOTES
Dec., 1946 factory; this has been verified. Yields of 6468y0of the 0-,m- and p-nitrobenzoylacetones have been obtained from the corresponding nitroacetophenones. The acetylation of o-nitroacetophenone may be represented as
,
NO?
2743
The Inhalation Toxicity of Ketene and of Ketene Dimer BY H. A. ~ V O O S T E RC. , ~ C . LUSHBAUGII ASD C. E.
RED EM AN^
The literature concerning the use of ketene in organic syntheses stresses its irritant q ~ a l i t i e s , ~ , ~ but contains no detailed statement of its toxicity. Preliminary tests indicated that freshly generated ketene was highly toxic.5
0 1
CH,COCH>CO~ -
--
NO.
Extended toxicity testing on mice, rats, guinea pigs and rabbits showed t h a t ten minute exposures to concentrations of freshly generated ketene as low as 0.2 mg./liter (116 p . p . m.) may produce a high percentage of deaths in small animals. Diketene is less than 0.1 as toxic. These findings put ketene in the same order of toxicity as phosgene4 (0.2-2.0 mg./liter) and hydrogen cyanide6 (0.20 . 5 mg./liter). Death is from pulmonary edema and is entirely similar to, b u t much more rapid than is the case with phosgene poisoning. A complete report of this study will be made elsewhere.
Since the nitroacetophenones are readily preparedJ5the present method for preparing the nitro 0-diketones is considered quite convenient.6 Gabriel and Gerhard’ have reported that onitrobenzoylacetone is reduced and cyclized in the presence of phosphorus and hydrogen iodide, Present address: 706 hlaloney Bldg., Hospital of t h e Cniveror stannous chloride and acetic acid, to form 2- s i t(1) y of Pennsylvania, Philadelphia 4, Pa. methyl-4-hydroxy-quinoline oxide. lZcCluskeyq ( 2 ) Present address: 770 South Arroyo P a r k w a y , Pasadena, Califound that this nitrogen oxide is converted to 2- f < r n i a . \ : j , K . T. Lf. XViIsmme, J . C h e w . Soc.. 91, 1938 (l!lOi), methyl-4-hydroxy-quinoline on boiling with zinc C . D . Ilurd and 0 . Kamm. “Organic Syntheses.” Vol. l V , dust and hydrochloric acid. \Ye have found that J o h( 4n) \Vile? and Sons, Inc., 1923, pp. 39-43. the nitrogen oxide is siniilarly obtained from oI
