4752
COMMUNICATIONS TO THE
EDITOR
i'ol. YO
animal organs and yeast (oily fractions). I t is clearly related to our coenzyme Q group. The authors are indebted to Dr. David E. Green for his encouragement in the course of these investigations.
27.5 and 407 in@)identified ; i s %,3-diniethoxy-3,Gdime thylbenzoquino~ie~. \Ye have studied the nuclear magnetic resonance spectra a t 40 mc. of Qlo and many synthetic model compounds, aiid Dr. James N. Shovlery (Varian CONTBIBUTION FROM R . I,. LESrEB Associates) has kindly determined the spectrum a t 00 me. These data characterize the INSTITUTE F O R ENZYME RESEARCH F. L CRANE of these data siio\i. convincingly that THEUNIVERSITY OF \#ISCOXSIN Y 114TEFI protons of QO: MADISON, WISCONSIN Ql0hss t'it o CH30--, one CH,-- and one isoprenoid RECEIVED A u c v s ~13, 1058 chain nf 10 units attached to a benzoquinone nucleus, but do not define the position of the ring --substittients. S.in.r. data esclude the presence of COENZYME Q. I. STRUCTURE STUDIES ON THE I COENZYME Q GROUP aromatic pi oh^^, -C=CH2 and --C&C&, and Sir: assign the ten double bonds in the isoprenoid side The discovery of a quinone, 9-27;, has been chain as in I. 'The n.rn.r. spectruin of eicosahyreported, and characterizing chemical and physical drocoenzyme Qlb siio\%sthe one =CCE& nucleus properties, oxidative degradation and hydro- group a t - 111..5 C.P.S. While this group is not genation are reported in an accompanying com- clearly resolved from -C-CH_,CI~,C== in the munication.2 Four closely related quinones having spectrum of Qlna t 40 mc., i t is a t GO mc. Reduction and methylation of Ql0 with dimethyl similsr coenzymatic activity have been isolated from microbial sources.2 AI1 five new quinones are sulfate, gavs a colorless crystalline tetramethoxy designated as members of a coenzyme Q group, derivative (IV), m.p. 38-30", [ a ] D 0' (chloroform). Foucd: C,81.85; H, 10.82,0CHd,14.2. ?.e., coenzyme Q6,( 2 7 , Q, Q g and QIO. Oxidation of IV with about a 4-foId e x e s s of We noTx have extended these observations. Formula I agrees with our structural data for aqueous alkaline permanganate a t 100' yielded coenzyme QIo (beef heart) and I1 and 111correspond tetran;etho:iS.pht~ialic anhydride (V) (after sublimation), imp. 13Y-1395 not depressed by admixto Q9,Qe, etc. ture of synthetic tctramethoxyphthalic anhydride.
Our isolated Qlo (yellow) melted a t 49.5-50.5'. Found: C, 81.98, 82.05; IH, 10.38, 10.31. H y drogenation of Qlo resulted in an absorption of about 11 moles of hydrogen. Oxidation of the resulting hydroquinone yielded eicosahydro-coenzyme Qlo; ),Laooctsne 278 mp, 187. Found: C, S0.30; H, l?%6. h'o.. of ~. ~
Proton type
HC= C&O=C-C&CH= =c-Cgr4!&--c= CI3C-( nucleus) CHsC=(chain)
i
C.P.S.~
+8 -34 -64, -69 -113
-125
protons No. of calcd. protons for Rela- based CrsHootivc on 0 4 and band 2CHsO/ strucareas mole ture I
5 3 1 20
10 0 2 40
16.5
33
-
10
6 0
Y
(36 (3 33
-
'.'
,.. I.
Oxidation of I V in acetone with the stoichiometric quantity of permanganate for ten double bonds gave aftcr partition chromatography, 2methyl-3,4,5,6-tetramethoxyphenylacetic acid (VI) m.p. 75-76', identical by melting point behavior and infrared spectra with a synthetic sample. The presence of levulinic and succinic acids as oxidation products was confirmed.2 The chemical and physical properties of synthetic 2,3-dimethoxy-5-methyl-6-farnesylbenzoquinone4 and analogs' are closely similar to those of Qlo. Ubiquinone! reported by Morton, et al., from animal organs (n1.p. range 33-41°)Gand yeast (yellow oily fractions)G is clearly related to the coenzyme Q group. DONALD E. WOLF CARLH. HOFFMAS NELSONR. TRENNER BYRON H. ARISON CLIFFORD H. SHVNK BRUCE0. LIXN JAMES F. MCPHBRSON KARLFOLKBRS RECEIVED A r ~ r 13, ~ s1958 ~
91 90 The bands refer to 40 mc. spectra in carbon tetrachloride, means a t lower fields than water protons while - means a t higher fields.
CONTRIBUTION FROM THE MERCK,SHARP& DOI.IMB RESEARCH LABORATORIES DIVISIONO F MERCR & eo., ISC. NEWJERSEY RAHWAY,
Coenzyme Q1o appears to be a 2,3-dimethoxybenzoquinone derivative. I t s absorption spectrum with maxima a t 275 mp and 405 mp is in good agreement with that of aurantiogliocladin, (maxima a t
-
+
7.
(1) P. L. Crane, Y. Hatefi, K. 1.. Lester and C. Widmer, Bidchim. Aiophw. Ac:o, 25, 220 (19571. (2) B. L. Lester, F. L. Crane and Y. Hatefi, T H I S J O U R N A L , 80,
(8) E. B. Visber. J . CAW:. SOL., 815 (1953). (4) C. H. Shunk. B. 0. I.inn. E. L. Wong, P. E. Wittreicb. I?. 37. Robinson and K. Folkers, Txirs J O I X N A I . . 80, 4753 (1958). ( 5 ) R. 8. Morton, G. If,Wilson, J. S. Lowe and W. M. I;. Lent, Chcm. & I n d . , 1649 (1957). ( 6 ) F. W. Henton, J S Lowe and R. A. Morton. J . Chem. SOC.,
4751 (1968).
4094 (19BG)
