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COMMUNICATIONS TO THE EDITOR
Deaks a t 3.29, 5.89 and 11.56 u (>C=CH,’I.
VOl. 79
at
On treatment with boron trifluoride etherate and a trace of water,4however, it is converted to a white crystalline solid, m.p. 300’ (d.). This new sub’Cipon- quantitative hydrogenation over Adams stance is insoluble in ether, chloroform or benzene, catalyst I absorbed three equivalents of hydrogen but can be dissolved in methanol and subsequently simultaneously. Formaldehyde, isolated as its recovered. It is reconverted by potassium cyanide dimedone derivative, was obtained upon reductive to (I). The analysis of the compound indicates ozonolysis of I. The triene rapidly added two that it is 1,2,3-triphenylcyclopropenylfluoborate equivalents of bromine a t room temperature, (11,X=BFI) contaminated with the hydroxyfluogiving rise to the tetrabromide VIII, m.p. 118-119’ roborate (11,X = BF3OH) ; (calcd. for C21H&F4: (eff.). Anal. Calcd. for Cl8HI4Br4:C, 39.31; H , C, 71.21; H , 4.27; F, 21.46. Calcd. f 0 r C ~ ~ H 1 ~ B F 3 0 : 2.57; Br, 58.13; mol. wt., 549.9. Found: C, C, 71.62; H, 4.58; F, 16.18. Found: C, 71.03, 39.01; H, 2.37; Br, 58.36; mol. wt., 509.2. VI11 71.18; H,4.56,4.38; F, 17.80, 18.31). in CHCls showed Amax 288 mp (log E 4.29) in the Consequently, the fluoroborate has been converted ultraviolet, consistent with a disubstituted cis- to a picrate, m.p. 195-196’ (11, X = C6H2N307); stilbene chromophore, and weak absorption a t (Calcd. for C27H17N307: C, 65.45; H, 3.46; N, 6.08 ,u in the infrared, attributed to the conjugated 8.48. Found: C, 65.50, 65.67; H, 3.55) 3.50; tetrasubstituted double bond. N, 8.59, 8.71). This compound is bright yellow, Acknowledgment.-This investigation was sup- indicating the presence of picrate ion, and is ported by a National Science Foundation research insoluble in benzene or ether. It is quite soluble in ethanol or methanol, however. While i t can be grant, for which the authors are deeply grateful. recovered from these solutions, prolonged standing THEBAKERLABORATORY O F CHEMISTRY CORSELLUSIVERSITY A . T BLOMQUIST leads t o some decomposition. ITHACA, NEW YORK YVONNEC. MEINWALD Thus the s-triphenylcyclopropenyl cation is RECEIVED AUGL-ST6, 1957 relatively stable, due of course in part to conjugation of the three phenyl rings with the positive charge. That it has some reactivity, as evidenced SYNTHESIS OF THE S-TRIPHENYLCYCLOPROPENYL by the slow decomposition in alcohols, may be in CATION part due to the strain resulting from the presence Sir: of three trigonal carbons within a three membered h h c h of the interest in the field of non-benzenoid ring. aromatic compounds centers around attempts to Acknowledgment.-The author wishes to acverify theoretical predictions that certain conjugated systems will be especially stable, or “aro- knowledge generous financial support by the du matic,” while others will not. These predictions Pont Company. (4) This procedure is based on a known method for preparing t h e indicate that, in addition to well-known aromatic cycloheptatrienyl cation (M. J. S. Dewar a n d R Pettit, J . Chem Soc systems containing six electrons and more, a three- 2026 (1956)) membered ring containing two electrons, the cy- DEPARTMENT OF CHEMISTRY UNIVERSITY ROSALDBRESLOW clopropenyl cation, should also be aromatic.’ We COLUMBIA wish to report the first preparation of a derivative NEW YORK27, N. Y. RECEIVED AUGUST 16, 1957 of this simplest aromatic ring. Reaction2 of diphenylacetylene with phenyldiazoacetonitrile yields 1,2,3-triphenyl-2-cycloproCRYSTALLOGRAPHY OF OCTACALCIUM pene carboxylic acid nitrile ( I ) ; m.p. 145-146’ PHOSPHATE (calcd. for C22H16N: C, 90.07; H , 5.13; N j 4.77; Sir: mol. wt., 293. Found: C, 90.22; H, 5.43; N, Although octacalciuni phosphate (OCP) was 4.91; mol. wt. (Rast), 286). The infrared spec- described long its crystallography is obscure. trum of (I) contains a band a t 4.3 p (C=N) and the Its relationship to hydroxyapatite is confused, ultraviolet spectrum is almost identical with that of and even its existence as a “discrete” compound l,2-diphenylcyclopropene-3,3-dicarboxylic ester.3 was questioned4 recently. An awareness of the The compound is soluble in non-polar solvents possible significance of OCP in agriculture5 and i n such as benzene, and gives no precipitate with biochemical processes prompted a study of its ethanolic silver nitrate solution. I t is thus cova- crystallography. lent. Very thin blades of OCP up to 250p long were Cs& C6Hr C6H5 CsHs prepared by slow hydrolysis of CaHP04.2H2O in a \ / \ / quiescent 0.5 W solution of sodium acetate a t 40”. The acetate solution was renewed when its fiH approached 6.1. The crystals closely approximated the formula Ca4H(P04)3,3H20 reported by Bjerrum,6 the average composition of three prepa(1) J. D. Roberts, A. Streitwieser. Jr , a n d C. \ I . Regan, THIS rations being Ca3.99Hl.02(P01)3.288H20. 7 4 , 4579 (1952). ( 2 ) This is one example of a n e w method f o r synthesis of cyclopropenes, t o be reported shortly. (3) S. F. Darling and E . W . Spanagel, THISJ O C R X A L , 53, 1117 (1931). We have also prepared this compound b y our new method (R. Breslow a n d R. Winter, A7n. Chein. SOL. Meeting Abstracts, S e w York, 1997,in press). JOURNAL,
(1) J. J. Berzelius, Ania., 63, 286 (1845). ( 2 ) R. Warington, I. Chein. SOL.,19, 29ti (1886). (:3) P. W. Arnold, I’vaizs. F a r u d a y Soc., 46, 1061 (19.50). ( 4 ) D . Carlstrdm, A c t a Radiol., Supplement 1 2 1 (1955). ( 5 ) J . R. Lehr and W. E. Brown, Soil S r i . Sac. A i n Proc., in press. (ti) X. Bjerrum. “Selected Papers,” Einar hlunksgaard, Copen-
hagen, 1949, p. 21.5.
