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COMMUNICATIONS TO THE EDITOR
1701. 78
Acknowledgment.-We would like to express our deep appreciation t o Professor E. M. Purcell for a valuable discussion on several of the above points. This work was made possible by generous grants from E. I. du Pont de Nemours and Co., Inc., and from the Esso Education Foundation.
0.04 AI a slight broadening, of the order of one oersted, was observed. If the broadening arises from the electron exchange reaction, the rate constant for the bimolecular exchange is 4 X lo8 liter mole-lsec.-l. The absence of broadening a t lower concentrations establishes this value as an upper limit, ie., k 6 4 x 108 liter rnole-'sec.-'. MALLINCKRODT CHEMICAL LABORATORY HARVARD UNIVERSITY AKSEL A. BOTHSER-BY Previous work with radioactive tracers3v4 has CAMBRIDGE, MASSACHUSETTS RICHARD E. GI ICK indicated that k> 4 X l o 4liter mole-lsec.-'. RECEIVED DECEMBER 25, 1955
PARAMAGNETIC RESONANCE OF OCTACYANOTCNGSTATEiV\L
Sir : The paramagnetic resonance of crystalline potassium octacyanotungstate and its aqueous solutions has been observed. A polycrystalline sample of composition K3\V(CN)~.0.55H20yields a single almost symmetrical resonance a t room temperature. The g value a t the center of the peak is 1.98. The breadth of the peak between points of extreme slope is 30 oersteds. An aqueous solution, approximately 0.01 M in U7(CN)s---, yields a symmetrical resonance of three lines. The central intense line occurs a t g = 1.972 with, breadth between points of extreme slope of 9.3 oersteds. The two satellites, each of intensity 7 + 3y0 of that of the central peak are separated by 52 oersteds. The central peak in all probability arises from ions containing Wla4which has zero nuclear spin and is 86y0 abundant; the satellites are the hyperfine components associated with \V183which has spin 1/2 and is 147, abundant. The spectrum of the aqueous solution is unusual in its sharpness. Owing to rapid relaxation processes, most paramagnetic compounds of heavy elements have lines so broad a t room temperature, that the resonances are not easily observed. The hyperfine coupling constant is unusually large, corresponding to a magnetic field of 6 X lo5 oersteds a t the tungsten nucleus. The results suggest the possible usefulness of TV(CN)S--- in experiments involving alignment of the nuclei of some of the radioactive isotopes of tungsten. The conventional description of W(CN)a--ascribes the paramagnetism to an unpaired electron occupying a d orbital. The isotropic hyperfine interaction here described requires admixture of a configuration containing unpaired electrons in s orbitals.* Further experiments with dilute solid solutions of TI'(CN)8--- in single crystals of a diamagnetic substance are required for more complete determination of the nature of the electronic wave function. An attempt was made to measure the rate of electron exchange between W(CN)s--- and UT(CN)s--- by the observation of the spectrum of the former in the presence of the latter. At concentrations of 1V(CN)8--- lower than 0.02 M no broadening of the hyperfine components of \TVla3(CK)s--- was observed. With \V(CP\T)8--- a t ( I ) T h i s work has been supported in p a r t b y t h e United S t a t e s Air Force through t h e Office of Scientific Research of t h e Air Research a n d Development Command and b y t h e United S t a t e s Atomic Energy Commission under Contract A T ( l l - 1 ) - 3 4 with t h e University of California. (2) A. Abragam, J. Horowitz a n d M. 13. L. Pryce, P r o c . R o y . Soc. (London), AWO, 169 (1955).
(3) E . L. Goodenow a n d C. S. Garner, THIS JOURNAL. 77, 5 2 7 2 (1955). (4) H . Baadsgaard and W. D . Treadwell, Helu. Ckim. Acta, 38, 1669 (1955).
WASHINGTON UNIVERSITY ST. LOVIS,MISSOURI UXIVERSITY OF CALIFORSIA
S. I. XEISSMAN
AT LOS A S G E L E S CLIFFORD S. GARNER Los ANGELES,CALIFORNIA RECEIVED FEBRUARY 6, 19SG
THE PARTIAL STRUCTURE OF NOVOBIOCIN (STREPTONIVICIN).' 11.
Sir:
The isolation and properties of novobiocin have been d e ~ c r i b e d . ~ -The ~ present studies, added to those previously reported,5 indicate that it is a CS sugar attached glycosidically to the 7-position of 2 - butenyl) - benzamidol3- [4-hydroxy-3-(3-rnethyl-
4,7-dihydroxy-8-methylcoumarin. Novobiocin (I) (C31H36N2011), is cleaved by the action of hot acetic anhydride to yield 4-acetoxy-3(3-methyl-2-butenyl)-benzoic acid (11) and a neutral compound, C23H26N2010 (111).5 Hydrolysis of I by 4 N hydrochloric acid in 607, ethanol gave an optically inactive acid, C22H21h'06 (IV), which upon cleavage with hot acetic anhydride yielded 2,Z-dimethyl-6-chromancarboxylic acid (VI) and an optically inactive neutral compound, C14HllN05(VII).5 In addition to IV, the acid hydrolysis affords an (1) T h e Upjohn C o m p a n y Registered T r a d e Xfark for novobiocin i s Albamycin. Our previous Communication5 on t h e s t r u c t u r e of this antibiotic is listed under our former generic n a m e , streptonivicin, now abandoned. T h e isolation of t h e same material b y t h e Xletck group has been described in THISJ O U R N A L77, , 6401 (195.5). T h e comparisons establishing identity are described b y H e n r y Welch a n d W. W. n'right i n Antibiotics oizd Chemothevnpy, 6 , 6 i O (1935). (2) (a) Streptonivicin, A S e w Antibiotic. I . Discovery and Biologic Studies, C. G. Smith, A . Dietz, W. T. Sokolski and G. M. Savage, Anlibinlics and Chemolhernpy, i n press, February, 1956. (b) 11. Isolation and Characterization, H . Hoeksema, hl. E. Bergy, W. G. Jackson, J. W . Shell, J . nT.Hinman, A. E. Fonken, G . A. Boyack, E. L. Caron, J. H . F o r d , W.13. Devries, a n d G. C r u m , ibid. (c) 111. I n V i f v o and I n V i v o Evaluation, J . R . Wilkins, C. Lewis a n d A. R. Barbiers, ibid. ( d ) 11'. .A Biological Assay for Body Tissues a n d Fluids, R . SI. Taylor, W. T . Sokolski, G. R I . Savage and %I. J . Vander Brook, ibid. (e) V. Absorption, Distribution a n d Excretion, R. L f . Taylor, W. L. 3Ziller a n d M .J . Vander Brook, ibid. ( f ) V I . Toxicology, E. John Larson, N. E. Connor, 0. F. SwoaP, R. A . Runnells, \ I . C. Prestrud, T . E . Eble, D'. A. Freyburger. W. Veldkamp and R. I f , T a y l o r , ibid., hfarch, 19.56. (8) Streptonivicin (Albamycin) A New 4ntibiotic; Preliminary Report, F. R . Heilman, D. R . Sichols, W. E. n'ellman, a n d J. E . Geraci, P r o c . St&'.Ileetings M a y o Clinic, 30, 540 (1955). (4) Streptonivicin, Laboratory and Climcal Studies in t h e Pediatric Age Group, Feng-Kai 1,in and L. L. Coriell, T h i r d Annual Symposium on Antibiotics, November 2-4, 1955; "Antibiotics Annual, 19551056," Welch a n d I I a r t i - I b a n e z , Xfedical Encyclopedia, I n c . , iXew York, N . Y . , i n press. (5) H e r m a n Hoeksema, James L. Johnson, a n d Jack W. H i n m a n , THISJ O U R N A L , 7 7 , 6710 (1955). New analytical d a t a for I and 111 have been obtained as follows: Calcd. for CiiHJeNiOii (I): C, 60.77; H , 5.92; N, 4.58. F o u n d : C , 60.62; H , 5.91; N,4.54. Calcd. for CzaH~aNrOio(111): C , 56.33; H , 5.35; N, 5.71. Found: C , 56.53; H . 5.33; N, 5.68.
