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COMMUNICATIONS TO THE EDITOR
hour fractionlo showed that 64y0 of the physiological activity had been destroyed. Since only 15y0of the methionine (position 4) and, therefore, also of the second serine (position 3) had been removed a t 4.5 hours, neither of these units could have been involved in the loss of activity. Thus one, or both, of the first two amino acids in the sequence appear to be necessary for physiological activity.'l Acknowledgment.-The author wishes to acknowledge the technical assistance of Mr. A . M. Gross.
Vol. 77
1
I
OCH,
OCHp
111
11
treatment with p-tosyl chloride in pyridine under normal conditions, to a high-melting (330-333", dec.) solid which we consider to be the quaternary (10) As control, a sample of corticotropin-.& was incubated f o r 4.5 salt I11 (Calcd.: C, 66.39; H, 6.90. Found: hours in t h e butier, b u t without aminopeptidase. No loss in activity was detected. T h e corticotropin-A sample used in this work had an C, 66.1s; H, 6.88),by reason of the following activity of 110 units per milligram of peptide. characteristics: (i) infrared absorption a t 8.2-8.6, (11) An interesting sidelight on t h e aminopeptidase reaction was 8.91, 9.62 and 9.86 p, indicative of the p-tosyloxy the effect of t h e hydrolysis on t h e solubility of corticotropin-A. At anion,6 (ii) ultraviolet absorption maxima a t t h e concentration used in t h e experiment ( 5 mg./ml.), corticotropin-A is n o t completely soluble a t p H 8.5. However, as t h e aminopeptidase 222 r n G (log B 4.70), 269 mp (log E 3.80) and 294 reaction proceeded, t h e cloudy appearance of t h e reaction mixture mp (log e 3.93), nearly identical with those of became less pronounced and by 4.5 hours had cleared completely. reserpinol hydrogen tosylate and therefore signiThus t h e first t w o amino acid units also appear t o he associated fying an unmodified indole ring, and (iii) in 66yc with t h e solubility of corticotropin-A. dimethylformamide, no titratable groups between THEARMOUR LABORATORIES CHICAGO, ILLINOIS IY.F. WHITE pH 3 and 13, and recoverable after treatment, in solution, with alkali.' It is apparent that the salt RECEIVED JULY 22, 1955 111, which possesses a bridged bicyclic system defined by atoms 4 and 15 through 22, can result T H E STEREOCHEMICAL FORMULATION OF RESERfrom N-4 attack on (2-22 of the unisolated IIPINE tosylate only if C-21 and the carbomethoxyl group Sir: originally present in reserpine are attached in a As an adjunct to studies taken up in the deriva- cis fashion to ring E. The above finding, coupled tion of the gross structures for reserpine with the equatorial nature of the carbomethoxyl and deserpidine (I with the C-11 methoxyl re- group as indicated by the stability of methyl reserplaced by hydrogen) , 3 there was obtained in- pate to sodium methoxide in boiling methanol,' is incorporated in the expression IT' for reserpine. / L A
formation requiring for reserpine a cis nature for the substituents a t C-16 and C-18l and also a cis juncture for the D and E ring^.^.^ We have now secured compelling evidence for a cis relationship of the hydrogens a t C-16 and C-20, which, in turn, taken together with certain previously recorded observations, provides for the complete stereochemical formulation of this complex base. Keserpinol (11) (Calcd.: C, 71.32; H, 8.16. Found: C, 70.96. H, 8.23), m.p. 254-255.5', obtained by lithium aluminum hydride reduction of methyl reserpate tosylate (V) was converted, on (1) L Dorfman, A . Furlenmeier, C. F. Huebner, R. Lucas, H. B . NacPhillamy, J. M . Muller, E. Schlittler, R. Schwyzer and A. F. S t . AndrC. Hciu. Chim. Acta, 37, 59 (1954). ( 2 ) N. Neuss, H. E. Roaz a n d J. W. Forbes, THIS JOURNAL, 76, 2463 (1954). (3) H. B. MacPhillamy, L. Dorfman, C. F. Huebner, E. Schlittler and A. F. St. AndrC, ibid.,77, 1071 (1955). (4) P. A . Diassi, F. L. Weisenburn, C M. Dylion and 0. Winteri t r i n e r i b i t i , 77, 2028 ( l ! l 5 , i J . (.-I) JC, 1;. vaii 'rameler~,1'. I> IIsncc, K . V . SivI>ra
