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1'01, 79
TO THE EDITOR COMMUNICATIONS
intestinal mucosa,3 and that it may be an intermediate in the biosynthesis of cholesterol. Evidence for the existence of demethylated intermediates in the conversion of lanosterol to cholesterol have been reported. l5 Acknowledgment.-We are indebted to Dr Hans No11 for infrared measurements, and to Drs. Klaus Hofmann and Arvid Ek for helpful suggestions.
(11). Finally, rescinnatnine and pseudoreserpinr have been correlated with reserpine216' (111, Y = OMe). However, no data chemically relnting the. three groups of compounds have been reported yet. Palladium-maleic acid dehydrogenationg of reserpine (111, Y = OMe) yielded its tetradehydro derivative (47%) as perchlorate, m.p. 194-1!)Ti0 (Found for C33H37013NzC1CH30H : C, Ei5.11; H , 6.02; N, 3.50). Hydrogenation of the latter with platinum in acetic acidg gave the demethoxytctra(15) F. Gautschi and K.Bloch TsI3 TOIIRNAI.. 79, 684 (19 57) hydrotetradehydro compound IV ( G l % ) , m.p. 1%BIOCHEMISTRY DEPARTMEKT UNIVERSITYOF PITTSBURGH WILLIAMW. WELLS 1S9', Xmpx 250 mp (log E 4.16)) 270 mp (log E 4.101 SCHOOL OF MEDICINE DEWEYH. NEIDERHISER and 335 mp (log E 3.61), [CY]D -40' (chloroform) PITTSBURGH, PENNSYLVANIA (Found for C32H3501~N2C1: C, 55.94; H, 5.25; RECEIVEDNOVEMBER 15, 1957 N, 4.25). The identical product, checked by m.p., mixed m.p., infrared and ultraviolet specTHE STEREOCHEMICAL INTERRELATIONSHIP OF tra, and specific rotation, was obtained by the cataT H E YOHIMBINE-TYPE ALKALOIDS' lytic hydrogenation of the tetradehydro derivative Sir : of deserpidine (111, Y = H).*b These results conWe wish to report the completion of the first stitute the first chemical correlation of compounds phase of our continuing studies of the stereointer- of group I1 and 111, and represent a potentially relationship of indole alkaloids containing the ring useful method of interrelating the many ring A system of yohimbine, ajmalicine and corynantheine, oxygenated ajmalicine-type alkaloids with alstoniiie ie., the steric relationship of all yohimbine-type and serpentine.2 alkaloids. Corynanthine, @-yohimbine and pseudoyohimbine have all been related to yohimbinej2whose absolute configuration (I) was ascertained by molecular rotation difference3and optical rotatory dispersion' studies. Similarly, alloyohimbine, rauwolscine, deserpidine, raunescine and isoraunescine have been interrelated with 3-epi-c~-yohimbine~,~,~
u\ I /
When apoyohimbic acid hydrochloride, readily derivable from yohimbine2 (I), was exposed to a Schmidt reaction, 16-yohimbone (V), m.p. 256' (dec.), [a]D -86.1' (pyridine) (Found for C19H22ONz: C, 77.7; H, 7.28; N, 9.3) was obtained in 17% yield.l0 The same reaction, carried out on the apo derivative of 3-e~i-a-yohimbine5~ (11),led to R ketone (17%) whose m.p. 254-256', [ a ] D +85.0° (pyridine), and infrared spectrum, identical with that of V, proved it to be the enantiomer of 16-yo-
\/0\
(1) This work was supported in part by a research grant from Ciba Pharmaceutical Products, Inc., and from the National Institutes of Health, Public Health Service, Department of Health, Education and Welfare (M1301). (2) For a review of t h e stereochemistry of indole alkaloids cf, J . E. Saxton, Quart. Revs., 10, 108 (1956). (3) W. Klyne, Cheinislry and Indurlry, 1032 (1953). (4) C. Djerassi, R . Riniker and B. Riniker, THIS J O U R N A L , 78, 6862 (1956). (5) (a) C. F. Huebner and E. Schlittler, ibid., 79, 250 (1957); (h) E. E. van Tamelen and C. W. Taylor, ibid., 79, 5256 (1957). (6) For a discussion of the absolute configuration of these alkaloids based on molecular rotation difference data cf. E. Schlittler, T h e Chemistry of Rauwolfia Alkaloids. in "Rauwolfia," I.ittle, Brown and C o m p a n y , Boston, 19\57.
l i
04%'
V (7) M. W. Klohs, F. Keiler, R . E. Williams a n d G W. Kussrrow, THISJOURNAL, 79, 3763 (1957). (8) (a) E. Wenkert and L. H. Liu, E r p e i i e n f i a , 11, 362 (1SB.jii; (b) E. Wenkert and D. K . Roychaudhuri, in press. (9) Cf. H. Schwarz and E. Schlittler, IIPIo. Chint. A r l i r 3 4 , 629 (1951).
(lo) Since the completion of this work t h e synthesis of I(i-ketu. yohimbane has been reported also by R K. H i l l : ~ n dK . X I u e n c i i , J. Org. Cizem., 22, 1276 (1957).
Dec. 20, 1957
COMMUNICATIONS TO THE EDITOR
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himbone (VI). l 1 The correlation of yohimbinetype alkaloids with D / E trans fusion with those of D,/E cis juncture thus is accomplished. The above data illustrate unambiguously for the first time that the only center of asymmetry common to all yohimbine-type alkaloids is C-15.12*13 (11) T h e Schmidt reaction of tetrahydroserpentic acid and tetrahydroalstonic acid does not lead t o ketones directly, b u t instead produces stable isocyanates. These results and further d a t a will be discussed a t a later time. (12) This fact was pointed o u t by A. K. Bose, B. G. Chatterjee and R . S. Iyer [ I n d . J. Pharm., 18, 185 (1956))in connection with their discussion of t h e absolute configuration of yohimbine alkaloids, based on molecular rotation difference data. (13) T h e authors are most grateful t o Drs. Huebner, Lucas, MacPhillamy and Schlittier for a generous supply of t h e compounds needed for this study and t o t h e Institute of Atomic Research, Ames, Iowa, for t h e use of a Baird infrared spectrophotometer.
DEPARTMENT OF CHEMISTRY
ERNESTWENKERT ERNEST W. ROBB AMES,I o m ~ X. V. BRINGI RECEIVEDNOVEMBER 6, 1957 IOWA STATE COLLEGE
OBSERVATIONS OB NEW PHENOMENA I N THE FLUORESCENCE SPECTRUM OF A DIPHOSPHOPYRIDINE NUCLEOTIDE-LINKED DEHYDROGENASE
350
400
450
500
550
600
WAVE LENGTH, m p ,
Fig. 1.
shown to be competitive with respect to pyruvate and non-competitive with respect to DPNH, it is Boyer and Theorelll have reported that the wave inferred that this spectral change results from the length of the maximum intensity of the fluorescence formation of an LDH-DPNH-oxamate complex. spectrum of reduced diphosphopyridine nucleotide The concentration of oxamate required to reduce (DPNH) shifts from 450 mp to about 415 mp when the intensity of the LDH-DPNH fluorescent specD P N H combines with liver alcohol dehydrogenase. trum to half its initial value is approximately the Inspection of the figure presented by these authors value of K I when oxamate is used as an inhibitor indicates that the intensity of fluorescence of the for the LDH-catalyzed reaction between D P N H M. alcohol dehydrogenase-DPNH complex is approxi- and pyruvate, ;.e., approximately The curve labelled DPKH-LDH-lactate was obmately 1.8 times that of D P N H alone. We have made similar measurements with crys- tained when Na-L-lactate, a t a final concentration M , was added to LDH and DPNH talline heart muscle lactic dehydrogenase using the of 4.3 X Aminco-Bowman recording spectrophotofluorime- present in the concentrations used for the other terS2 The fluorescent spectra shown in Fig. 1 were curves. The wave length of maximum emission is measured in 0.05 M phosphate buffer, p H 6.88, a t shifted to 420 m p . The high concentration of lacroom temperature using an activating wave length tate required to produce this effect, which preof 340 mp. The curve labelled L D H was obtained sumably arises from an LDH-DPNH-lactate comM lactic dehydrogenase. The plex, is consistent with the observation that lacwith 8.4 X molecular weight of the enzyme was taken as tate has essentially no effect as an inhibitor of the 135,000.3 The curve for D P N H was recorded a t a LDH-catalyzed reaction between D P N H and pyruD P N H concentration of 2.5 X M . When Sate. The addition of oxamate to a concentration M results in the curve labelled DPNHD P N H and LDH were each present a t the concen- of 2 X tration used for the measurement of their separate LDH-LACTATE-OXAMATE. Results previously published from this Laboraspectra, the curve DPNH-LDH was obtained. The wave length of maximum fluorescent emission tory5v6indicate that a ternary LDH-DPNH-pyoccurs a t 430 mp as compared to 455 mp for ruvate complex is the reactive intermediate in the DPNH. Preliminary experiments indicate that reaction catalyzed by LDH. Kinetic results also the maximum shift in fluorescence occurs when the indicate that oxamate acts as an inhibitor by formratio of D P N H concentration to LDH concentra- ing an unreactive LDH-DPNH-oxamate complex. Since the addition of diphosphopyridine nucleotide tion is approximately four. (DPN), which does not itself fluoresce, t o LDH The addition of pyruvate to the DPNH-LDH system to a final concentration of 1.2 X M causes no change in the fluorescent spectrum of results in a rapid change to the spectrum of LDH LDH, the present results suggest that in the LDHalone. Surprisingly, the addition of oxamate to DPNH-oxamate complex the bonding electrons of the same concentration results in a similar change. D P N H are constrained in a configuration resemSince oxamate has been shown to be a powerful in- bling the aromatic ring of DPN. Moreover, since hibitor for the enzymatic reaction4 and has been no net reaction occurs, i t is possible that the LDHDPNH-oxamate complex is an abortive complex (1) P. D. Boyer and H . Theorell, Acta Chcm. Scond., 10, 447 (1956). similar in structure to the activated complex ( 2 ) R . L . Bowman, P. A. Caulfield and S. Udenfriend, Science, 122, formed between LDH, D P N H and pyruvate. 32 (1955). ( 5 ) M. T. Hakala, A. J. Glaid and G n'. Schwert, J B i d C b t , ~ . , (3) J. B. Keilands, J . Biol. Chem., 208. 225 (1954).
Sir;
(4) M. T. Hakala, A . J. Glaid a n d G. W. Schwert, F e d e m l i o n Proc.,
12, 213 (1953).
221. 191 (19561. , . (6) Y . Takenaka and G . XI', Schwert, ibid.,2 2 3 , 157 (195G)
