Vol. 60
2566
COMMUNICATIONS T O T H E EDITOR THE QUANTUM YIELD OF CEJLOROACBTIC ACID HYDROLYSIS
locations for such an oxygen atom led to the conclusion that it must occupy position 11or 12 of the Sir: steroid nucleus [Kendall, Mason, Hoehn and McKenzie, Proc. S t a . Meet. Mayo Clinic, 12, 136,270 Following the report by Rudberg [Z. Physik, (1937) ; Steiger and Reichstein, Helv. Chim. Acta, 24,247 (1924)l of a quantum yield of unity for the 20, 517 (1937)l. Steiger and Reichstein [HeZv. hydrolysis of monochloroacetic acid in aqueous Chim. Acta, 21, 525 (1938)] have recently comsolution at 2537 A., this reaction has been empared the acid (our acid 1) obtained by oxidation ployed in a number of cases as an actinometer. A deviation in the results obtained with the of corticosterone (our compound B) with the uranyl oxalate and chloroacetic acid actinometers 3, I 1-diketo-A4-etio-cholenicacid prepared by dega t 2537 A. has led us to reinvestigate both reac- radation of digoxigenin and have found it to be tions. A solution 0.01 ill in uranyl sulfate and different. They consider that this result casts 0.05 M in oxalic acid gave an average quantum doubt on position 11 as the location of the oxygen yield of 0.60, in agreement with the value re- atom in question although it is not conclusive in ported by W. G. Leighton and Forbes for this view of the possible isomerism of the steroid skelewave length [THISJOURNAL, 52, 3139 (1930)l. ton. We have made a similar comparison with For a solution 0.5 M in monochloroacetic acid, at 3,12-diketo- AP-etio-cholenicacid and have found 25' and an incident intensity of 2 X 10l2to 1 X that the acid derived from corticosterone differs 1013quanta/mm.2 sec., we find a quantum yield of widely in its properties. This result eliminates 0.3 to 0.4a t 2537 A. This result has been checked the possibility that the oxygen atom in question on two independent experimental set-ups, using occupies position 12 of a normal steroid nucleus. different thermopiles and standard lamps as well The close similarity of the behavior of this oxygen as different samples of chloroacetic acid. Amount atom with that of the oxygen atom of sarmentoof hydrolysis was determined in both cases by genin which has been assigned to C-11 argues for potentiometric titration of the chloride ion. 'The an identity of position. Degradation of sarmenresults show some variability the source ()I togenin, which is known to differ from digoxigenin which has not been located. 'There seems little only in the configuration of 1 asymmetric center, doubt, however, but that under our conditions thc probably C-9, should yield a definite answer to quantum yield a t '.'5:37 A. is much below unit), this problem. The degradation of desoxycholic acid to 3,12and we wish to call this to the attention of ally who may be using or considering the use of thi. diketo-etio-cholanic acid has been described [Hoehii and Mason, THIS JOURNAL, 60, 1493 reaction as an actinometer. Bromination in acetic acid solution gave (1938)]. DEPARTMENTS OF CHEMISTRY li', G. LEIGHTOX R. N.SMITH -C-bromo-3,12-diketo-etio-cholanic acid, m. p. 197POMONA COLLEGE AND STANFORD UNIVERSITY 1'. A . LRICHTON 1 0 8 O (dec.); [aIz5~61 109 * 2'. (Calcd. for CALIFORNIA C20H2,01Br: C, 58.52; H, 6.64; Br, 19.42. RECBIVRDS W T E M ~19, ER 19:;K Found: C, 58.40; H, 6.65; Br, 19.19.) This bromo acid lost hydrogen bromide when re0uxed with pyridine to yield 3,12-diketo- A'-etW-cholenic LOCATION OF OXYGEN IN CERTAIN STEROIDS acid, m. p. 205-207'; [ a ] 2 5 ~ 6 1 +240 * 5'. Sir: (Calcd. for GaHzaO4: C, 72.68, H, 7.93. Found: In certain compounds of a steroid nature which C, 72.35; H, 8.24.) Our acid 1 melts a t 267~ ~ MUse ~~ of the methyl esters occur in the adrenal gland there is an atom of 269'; [ ( Y I+291". oxygen which is exceedingly inert whether in the gave better yields and the final product was more form of a ketone or of a hydroxyl group [Mason, readily purified. The ester of the bromo acid 61 * 3". (Calcd. Hoehn, McKenzie and Kendall, J . Biol. CFem., melts at 200-201"; [ a l Z 5 ~+170 120, 718 (1987)j. Consideration of the possible for CS,H29C)4Rr: Hr, 18.79. Found: Br, 18.94.)
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