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COMMUNICATIONS TO THE EDITOR
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of 3-hydroxy-5,6-diphenyl-l -pyrazolo [b]pyrazine THE PREPARATION OF THE NEW COMPOUND CALCIUM COBALTATE(II1) (VI, R = - H, R' = - C6H5)with Raney nickel in boiling ethanol solution for three hours gave in 80% Fir: yield 2-aniino-5,6-diphenylpyrazine-3-carboxamide Although compounds of BaO and MgO with COZ(VII, R = -H, R ' = -C&), m.p. 203-205", 0 3 have been prepared as summarized by iMellor,' identical in all respects with an authentic sample an attempt to prepare the compound CaOCoeOj prepared previ0us1y.l~ Similar cleavage of VI under similar conditions was not successful. (R = -CH3, R ' = -H) yielded 2-methylaminoDifficulty in obtaining exact stoichiometry with pyrazine-3-carboxaniide7 (VII, R = -CH3, R' = cobalt compounds and the desirability of obtaining -H, rn.p. 200-201". Anal. Calcd. for CeHSON4: intimate mixture of reactants led to the following C, 47.4; H, 5.3; N, 36.8. Found: C, 4i.5; H , preparative procedure. Exactly one molc of CO5.3; N, 36.6). In a trial experiment, this reaction baltous oxide which had been calcined a t 950" sequence leading to the pyrazine intermediates was under vacuum to insure absence of highcr oxides shortened by several steps by direct condensation was dissolved in hydrochloric acid and cobaltous of 3-hydroxy-4-nitroso-5-aniinop~-razole (Y, R = hydroxide was precipitated with base. The pre-H) with biacetyl in ethanol solution in the pres- cipitate was washed by decantation without loss ence of Raney nickel to give 2-amirio-5,6-dimethyl- until analysis showed absence of chloride ion in the pyrazine-3-carboxamide (VII, R = -K, R' = wash water. Precipitated calcium carbonate (1.00 -CHa, m.p. 2 Z 0 . Anal. Calcd. for C7H100Kl: mole) was stirred into the cobaltous hydroxide, arid C, 50.6; H , 6.1; K, 33.;. Found: C, 50.6; H, the mixture was filtered. After drying a t l l O o , the 6.1; N, 33.2) directly, the Kaney nickel effecting mixture was calcined a t 1100" for several hours in both the reduction of the nitroso group and the ring air. hnalysis of the product corresponded to the cleavage of the subsequently formed pyrazolo [b]- formula CaOCoz02.67. pyrazine. was put in A sample of 10.00 g. of Since pteridines may be prepared directly from a porcelain boat in a vacuum system a t 5.25' in an these intermediates by known r n e t h ~ d s , l - ~the . ~ atmosphere of oxygen Reaction a t this teniperareactions outlined above constitute a new total syn- ture was extremely slow, taking about three days thetic approach to these important heterocycles. to absorb suficient oxygen to form a compound of formula CaOCo203. (13) E. C. Taylor, THISJ O U R N A L , 7 4 , 1631 (1952). A second 10.00-g. sample of the same material FRICK CHEMICAL LABORATORY PRINCETON UNIVERSITY T. S. OSDEXE was allowed to react with oxygen a t 660". After PRINCETON, NEW JERSEY E C TAPLOR 52 hours the pressure would decrease no further. Analysis agreed with the formula CaO.Co& RECEIVED A m w s i - 31, 1936 Analysis of Co(II1) content of all samples was carried out by solution in hydroiodic acid and titraAN EXPLOSION DURING THE PREPARATION OF tion of the liberated iodine with thiosulfate. DIAZOACETONITFULE Evidence of a probable chemical binding of calSir: cium oxide in the compound is afforded by the obThe preparation of diazoacetonitrile has recently servation t h a t the calcium oxide in the compound been described' and we have repeated the procedure could not be converted to soluble calcium hydroxon several occasions without incident. However, ide by placing in water a t room temperature for a violent explosion occurred during one preparation 24 hours. The compound was slowly hydrolyzed and the operator was seriously injured as a result. by boiling 1 molar ammonium nitrate solution. A concentrated solution of approximately 15 g. Further, the compound would not absorb nitrogen of diazoacetonitrile in methylene chloride was un- dioxide from a dilute mixture with air in the temder water-pump vacuum in a four liter suction perature range 250 to 350" as does calcium oxide flask. The temperature was approximately 10" alone. when the operator allowed air to enter the system. At room temperature the compound CaOConOd When the rubber stopper bearing the capillary was has qualitatively the same magnetic properties as removed, the explosion resulted. does C0203. It is probable t h a t some pure diazoacetonitrile (1) J W. Mellor, "A Comprehensive Treatlse of Inorganic and was between the rubber stopper and the neck of the Theoretical Chemistry," Longmans, Green 8; Co., New Yurk, N Y , flask and the friction generated by removing the 1938, vol XIV, p 594. stopper was sufficient to initiate the explosion. I t DEPARTMENT O F CHEMISTRY
i s important that the nitrile be used only in dilute solution because it i s highly explosive in concentrated form. A similar incident has been during the attempted distillation of diazoacetonitrile but its highly explosive nature even in the presence of solvent has not been stressed adequately. (1) S. H. Harper and K. C. Sleep, J. Sci. Food A g r . , 6 , 116 (1958). (2) M. J. S. Dewar and R. Pettit, J . C h o n . Soc., 2026 (1956).
CHEMICAL ENGINEERING JAMES D. RAT STANFORD USIVERSITY A . Occ, JR CALIFORNIA RICHARD RECEIVED riUGUST 22, 1956 AND
L-RIBULOSE-~-PHOSPHATE : FORMATION BY PTJRIFIED KINASE FROM AEROBACTER AEROGENES Sir :
Lampen' has reported the enzymatic interconBAKERLABORATORY OF CHEMISTRY CORNELL UNIVERSITY DONALD D. PHILLIPS version of Id-arabinose ti L-ribulose by extracts of ITHACA, NEW YORK WILLIAMC. CHAMPION (1) J. 0. Lampen, A b s f r . Proc. Amcr. Chcm. Soc., SPpt., 10.74, RECEIVED SEPTEMBER 17, 1956 44c-45c.
