[CONTRIBUTION FROM
GEORGES. Cox MEDICAL RESEARCH INSTITUTE, OF PENNSYLVANIA] UNIVERSITY
THE
INVESTIGATIONS ON STEROIDS. 11. ~(cY)-HYDROXYPROGESTERONE’ MAXIMILIAN EHRENSTEIN
AND
THELMA 0. STEVENS
Received April 1, 1040
As was pointed out in a previous paper (l), progesterone is the only naturally occurring compound with pronounced progestational activity. It manifests a slight “cortin” action, in that large doses are capable of maintaining the life of adrenalectomized animals (2). Desoxycorticosterone (21-hydroxyprogesterone), which was synthesized (3) previous to its isolation from the adrenal cortex (4),appears to be the simplest type of chemical compound having adrenal cortical activity. It also has a progestational effect about one-tenth that of progesterone ( 5 ) . After the discovery of desoxycorticosterone, it waa anticipated that this substance would alleviate equally well all the different physiological manifestations of adrenal insufficiency. More recent investigations have shown, however, that although desoxycorticosterone is highly satisfactory in maintaining the life of adrenalectomized animals, it is less effective than the other adrenal cortical hormones when, for example, the aggravation of diabetes (6) or the prevention of muscle fatigue (7) is measured. These other hormones are derivatives of desoxycorticosterone which are oxygenated a t carbon atoms 11 or 17, or both. In the light of these physiological facts it appears desirable to synthesize other compounds which are derived from progesterone or desoxycorticosterone and contain additional oxygen atoms attached to different carbon atoms of the sterol nucleus. It remains to be seen to what extent such compounds will manifest progestational or adrenal cortical action. At least two different monohydroxyprogesterones with the hydroxyl group attached to the nucleus have been described. The 12-hydroxyprogesterone which was synthesized from desoxycholic acid (8) possesses only slight, if any, progestational action. No reference to adrenal cortical activity is given. Pfiffner (9) recently isolated from beef adrenal glands 1 Aided by a grant from the Smith, Kline, and French Laboratories in Philadelphia. Read before the American Society of Biological Chemists at the annual meeting of the Federation of American Societies for Experimental Biology, in New Orleans, La., March 15, 1940. 318
INVESTIGATIONS ON STEROIDS
319
a 17-hydroxyprogesterone which probably possesses at carbon atom 17 the same configuration (6) as certain adrenal cortical hormones (17-hydroxycorticosterone, 17-hydroxy-11-dehydrocorticosterone, 17-hydroxy11-desoxycorticosterone). It has, however, only slight, if any, ‘(cortin” action. When it was assayed at a five milligram dose level with a modified Clauberg technique, no progestational activity was found. The attempts of other workers to obtain by synthetic methods the 17(a)hydroxyprogesterone have thus far met with failure. Apparently this compound is unstable and undergoes rearrangement very readily (10). Two isomeric monohydroxyprogesterones were recently (11) described in which the hydroxyl group appears to be attached to carbon atom 2. They were obtained by the action of lead tetra-acetate upon progesterone. Physiological data are not available. I n a preceding paper (1) the preparation of 6-oxoprogesterone waa described. It possessed no progestational activity. In the meantime, D. J. Ingle has found that this substance does not protect adrenalectomized rats against the manifestations of adrenal insufficiency when administered in doses as large as two milligrams per day. The intermediates in the preparation of 6-oxoprogesterone were the triols I1 or I11 which were obtained by treating 5-pregnene-20-one-3-01 (I) with hydrogen peroxide or osmic acid respectively. Both triols2 have identical stereochemical structures, presumably coprostane configurations, at carbon atom 5. They differ in configuration at carbon atom 6. The relative position of the hydroxyl groups at carbon atoms 5 and 6 is (‘trans” in compound I1 and ‘‘cis1fin compound 111. It ought to be poasible to obtain from compounds I1 and I11 respectively two stereoisomeric 6-hydroxyprogesterones which differ only with regard to the configuration at carbon atom 6. Thus far we have been successful only in preparing a substance which is derived from compound 11. By acetylation, the 3 ,6diacetate was obtained (IV). Under special precautions the saponifica-
* Ellis and Petrow ( J . Chem. Soc., 1939, 1078) recently investigated the stereochemical configuration of the cholestane-3,5,6-triols. The triol obtained by treating cholesterol with osmic acid was assigned the ooprostane configuration, which is in agreement with the stereochemical considerations of our previous paper (1). The triol obtained by means of hydrogen peroxide was assigned the cholestane configuration. The fact t h a t in our series the procedure with hydrogen peroxide apparently furnished the coprostane configuration is no contradiction. Probably the hydrogen peroxide treatment of cholesterol acetate and of 5-pregnene-20-one-3-01 acetate respectively furnished in each case a mixture of two “trans” forms, one possessing the coprostane configuration and the other the cholestane configuration. It appears t h a t in the experiments with cholesterol the cholestane epimer was secured from this mixture, whereas in our experiments with pregnenonol the coprostane epimer showed the greater tendency t o crystallize.
320
MAXIMILIAN EHRENSTEIN AND THELMA 0. STEVENS 20
Ia. R = H Ib. R = AC
20
21
21
21
CO-CHa
-cHs
CO-CHa CHRI
-
saponlficatlon
RO
4
OH II. Pregnane-aO-one-3(0)5,6(trans)-triol.
Ib. 5-Pregnene-20-one3-01 acetate.
20
21
20
21
20
OH I I I. Pregnane-20-one-3 (0) 5, G(cis)-triol.
OAc
OAc
IV. Pregnane-%one-3 (a)5,6(trans)-triol 3,6-diacetate.
V. Pregnane-U)-one-3(a) 5, G(trans)-triol &monoacetate.
20
21
CO-CHs
CO-CHs
21
20
VI. Pregnane-3,20-dione5,6(trans)-diol 6-monoacetate. I
20
21
IHCl
CO-cHs
21
CO-CHs
KOH 0
0 0 IX. Pregnane-3,6,20-trione. (or Allopregnane-3,6,2O-trione)
OH VIII. PPregnene-3,20-dione6((~)-01. [6 (a)-Hydroxyprogesterone] FIGUREI
OAo VII. 4-Pregnene-3,N-dione6(a)-o1 acetate. [6(&Hydroxyprogesterone acetate]
INVESTIGATIONS ON STEROIDS
321
tion of one acetyl group only was carried out. We believe that the hydroxyl group was set free a t carbon atom 3 rather than a t carbon atom 6 for reasons which will be given later. Therefore the product of saponification has been assigned the structure of pregnane-20-one-3 (P)-5, 6(trans)t.riol 6-monoacetate (V), Oxidation of t'his substance with chromium t'rioxide furnished pregnane-3,20-dione-5 ,6 (trans)-diol 6-monoacetate (VI). Compound VI was dehydrated with the aid of dry hydrogen chloride in chloroform solution. Thereby, 4-pregnene-3,20-dione-6(a)-ol acetate [6 (a)-hydroxyprogesterone acetate ] (VII) was obtained. The T
0
FIGURE 11. Absorption curve of 6(a)-hydroxyprogesterone acetate (in absolute alcohol)
prefix a is arbitrarily used to indicate the configuration of the hydroxyl group at carbon atom 6. It would be interesting to transform hyodesoxycholic acid into a 6-hydroxyprogesterone and to establish whether the hydroxyl group a t carbon atom 6 possesses the a or /3 configuration. The ultraviolet absorption spectrum3 of compound VI1 (Figure 11) is in agreement with the proposed structure of the acetate of 6(a)-hydroxyprogesterone. The wave length of the maximum (232 mp) is somewhat short; it is, however, not inconsistent with a ,P-unsaturated ketones of this type 3 We are indebted t o Professor George R. Harrison and to Mr. Kent of the Department of Physics of the Massachusetts Institute of Technology for the determination of the ultraviolet absorption spectrum.
322
MAXIMILIAN EHRENSTEIN AND THELMA 0. STEVENS
(12). The molecular extinction coefficient of about 14000 is in good agreement with the suggested structure. If the partial saponification of the diacetate IV had taken place at carbon atom 6, the dehydration product of the saturated 3,20-diketone would have to be assigned the structure of 4-pregnene-6,20-dione-3(&01 acetate (X).
E ( C H 2 Ih E
z2jqk
A/l
AcO
0 X. 4-Pregnene-6 ,20-dione3(j3)-ol acetate
f€&€&5 AcO
0 XI. 4-Cholestene-6-one-3(&01 acetate
A compound with a corresponding structure (XI) is known in the cholestane series; it was described by Heilbron, Jones, and Spring (13). The ultraviolet absorption spectrum has the maximum at 236 mp; the molecular extinction coefficient is as low as 6300. This latter feature appears to be noteworthy. Heilbron and his collaborators state explicitly that their compound (XI) gives a yellow coloration with tetranitromethane in chloroform solution, a reaction which is unusual for an a,@unsaturated ketone. The fact that our compound gives no yellow color with tetranitromethane in chloroform solution is another support in favor of structure VII. It may be mentioned that cholesterol can be transformed with the aid of hydrogen peroxide into a cholestane-3 ,5,6-triol. This compound probably possesses cholestane configuration. The 3,6-diacetate can be hydrolyzed to a 6-monoacetate (14). This affords another instance in which the ester group at carbon atom 3 is preferentially saponified. Although the diacetate of cholestane-3 ,5 ,6-triol and compound IV of this paper possess identical stereochemical configurations (P) a t carbon atom 3, it must be borne in mind that the configurations at carbon atoms 5 and 6 are probably opposite. The two compounds are therefore stereochemically only partly analogous and the similar course of the partial saponification may only be incidental. An attempt was made to saponify the acetate of 6(a)-hydroxyproges-
INVESTIGATIONS ON STEROIDS
323
terone (VII) to the corresponding non-esterified compound (VIII). Even under mild experimental conditions the free 6(a)-hydroxyprogesterone (VIII) could not be secured. The molecule is apparently very unstable and rearranges to an isomer which is probably pregnane-3,6,20trione (IX). This substance showed an absorption maximum a t 251 mp with a molecular extinction coefficient of about 1700 (in alcohol). There is little probability that these figures are due to the presence of some 6(a)hydroxyprogesterone (VIII), because the acetate of the latter compound has its maximum at 232 mp. We do not venture to decide whether the figures obtained can be attributed to pregnane-3,6,20-trione (IX) or still another isomer. The substance obtained (IX) was accompanied by material melting over a wide range, which therefore represented a mixture. When this mixture was heated with alcoholic hydrochloric acid, it could be transformed into a homogeneous substance which proved to be identical with the above compound assumed to have structure IX. When IX4 was treated with acetic anhydride and pyridine, it was recovered unchanged. This indicates also that it cannot be the free 6(a)-hydroxyprogesterone (VIII). These relationships resemble those in the cholestane series, in which 4cholestene-3-one-6-01 (14) and 4-cholestene-6-one-3-01 (13) respectively, are rearranged under the influence of alcoholic alkali or hydrochloric acid to cholestane-3,6-dione. Experiments are under way to obtain the 6(p)-hydroxyprogesterone from pregnane-20-one-3(8)-5, G(cis)-triol (111). We have found that it is not feasible to subject the 3 ,&diacetate, which is described in the experimental part of this paper, to the series of reactions outlined above. When partial saponification of the diacetate was attempted, it was found that the rate of hydrolysis was about the same at carbon atoms 3 and 6, so that some other means of transformation must be sought. The acetate of 6(a)-hydroxyprogesterone (VII) was subjected to a preliminary physiological examination. We are indebted to Dr. A. W. Makepeace for testing this substance for progestational activity. Five milligrams produced a strong response (+ +) in the Corner-Allen test, 3 milligrams was positive (++),and 1 milligram failed to cause a distinct uterine response. This means that the acetate of 6(a)-hydroxyproges-
++
4 A very small amount of this compound was used for preparing an oxime. The resulting substance, which was not pure, melted between 185" and 170". Calc'd for CzlHasNsOs (Trioxime) : N, 11.20 C Z ~ H Z Z N(Dioxime): ZO~ N, 7.78 Found : N, 10.03 The result of the analysis indicates that the substance must consist mainly of a trioxime, a finding which is in agreement with the above discussion.
324
MAXIMILIAN EHRENSTEIN AND THELMA 0. STEVENS
terone is the first monohydroxyprogesterone which has been found to manifest a distinct progestational effect. At present only two other compounds with pronounced progestational activity are known, namely progesterone, which gives a positive response in the Corner-Allen test with 1 milligram, and pregneninonol (17-ethinyltestosterone, anhydrohydroxyprogesterone), which is about one-third as active6. Preliminary tests by D. J. Ingle indicate that adrenalectomized rats treated with 2 milligrams daily of the acetate of 6(a)-hydroxyprogesterone (VII) gain in body weight and perform more work than untreated animals. The number of tests is too small to permit a final conclusion. EXPERIMENTAL
All melting points were determined with the Fisher-Johns melting point apparatus of the Fisher Scientific Company (Pittsburgh, Pa.). The readings are sufficiently near the true melting points so that no corrections have been made. All microanalyses were carried out by Mr. William Saschek, Columbia University, New York. Pregnane-~~-one-SGB)-6 ,G(trans)-triol S,B-diacetate ( I V ). Pregnane-20-one-3 @)5,6(trans)-triol was prepared according t o the procedure given in the preceding paper (1). The average yield of three experiments was 30%. A solution of 1.94 g. of triol in 19.5 cc. of acetic anhydride was refluxed for 1.5 hours and was then poured into water. After the precipitated material had solidified t o a crystalline mass, i t was filtered, washed with water, and dried in VQCUO. The crude diacetate (2.26 g.) was recrystallized from methanol. Several fractions, totalling 1.93 g., with melting points ranging between 215' and 219", were secured. The average yield of constant-melting material of three experiments was 74%. Before analysis, the sample was repeatedly recrystallized from methanol; the melting point was 215.5216.5'; beautiful macroscopic plates, [a]: -2.0" (84.6 mg. in 2.0 cc. of acetone). Anal. Calc'd for CzsH~sOe:C, 69.08; H , 8.82. Found: C, 68.68, 68.86; H, 8.68, 8.88. Pregnune-~~-one-9~)-6,6(trans)-triol6-monoucetate ( V ) . T o a solution of 1.95 g. of the above described diacetate (IV) in 136 cc. of absolute alcohol was added, over a period of two days, in 25 equal fractions, a total of 48.75 cc. of 0.1 N solution of potassium hydroxide in absolute alcohol (calc'd for 1mole KOH: 44.85 cc.). Thereafter the solution was made neutral to litmus by the addition of dilute acetic acid. I t was brought to a small volume i n VUCUO, and water was added to the warm concentrate until a turbidity appeared. On cooling, crystallization began almost a t once. After filtering, 1.15 g. of material was secured; the melting point was 217-223". On concentrating the mother liquor, two more crops, totalling 0.53 g., were secured; the melting points were variable, but above 200'. The fractions were dissolved separately in a little methanol; on adding ether, crystallization began a t once. The total yield of material melting above 212" was 1.36 g. The average yield of fairly pure material of three experiments was 71%. A sample was again recrystallized for microanalysis. It was dissolved in a large volume of ether to which some petroleum ether was added. On concentrating to a small volume, a white crystalline precipitate appeared; platelets of various shapes melting a t 222-226". 6 A. Wettstein just (March 15,1940; Helv. Chim. Acta,23,388) described the preparation of 6-dehydroprogesterone, a compound which produced a corpus luteum hormone effect about half t h a t of progesteron.
325
INVESTIGATIONS ON STEROIDS
Anal. Calc'd for CesHasO5: C, 70.36; H, 9.25. Found: C, 70.20, 70.05; H, 9.35, 9.36. Pregnane-$, 90-dione-6, G(trans)-dioZ 6'-monoacetate ( V I ) . One hundred and sixty milligrams of fairly pure pregnane-20-one-3@)-5, G(trans)-triol 6-monoacetate (V) was dissolved in 5.0 cc. of glacial acetic acid and the solution cooled to room temperature. Then 50 mg. of chromic oxide (calc'd for 1 atom 0: 27.2 mg. Cr03) dissolved in 2.0 cc. of 80% acetic acid was added and the mixture allowed t o stand overnight. After the addition of 4 cc. of alcohol, the solution was concentrated almost t o dryness i n vacuo. T o this residue water was added, giving a white precipitate, which was filtered and washed with water. The precipitate was suspended for several minutes in N sodium carbonate solution in order t o remove any acid material present. It was again filtered, washed with water, and dried i n vacuo; yield 131.2 mg. This crude material proved to be a mixture. It was dissolved in a rather large amount (about 15 cc.) of 95% alcohol on the water-bath and then concentrated to a somewhat smaller volume. On removing this solution from the water-bath, crystallization (glistening scales) began at once. The crystals were filtered the next day, washed and dried. The yield was 35.7 mg.; this material melted a t 260-262" to a dark brown fluid. The conjecture that this substance might be impure pregnane-3,6,20-trione5-01 [melting point 268.5-269.5", see compound XI11 of preceding paper (l)],proved to be correct. The mixed melting point of the two substances was about 264-267'. This would indicate that the starting material of this experiment contained some completely saponified pregnane-2O-one-3@)-5, G(trans)-triol (11). After the separation of the trione, the filtrate was concentrated to a very small volume. Crystallization began almost a t once; two crops totalling 73.6 mg. were secured; the melting points were 214-216" and 214-215.5" respectively. The combined material was recrystallized from a small volume of 95% alcohol; scales and prisms, showing rosette arrangement, melting point 215-217.5". The mixed melting point with the diacetate +23.3" (18.8 mg. of pregnane-u)-one-3@)-5,6(trans)-triol (IV) was 175-180"; in 2.0 cc. of acetone). Anal. Calc'd for CzsHsrOs: C, 70.72; H, 8.78. Found: C, 70.66, 70.52; H, 8.74, 7.82. This experiment was repeated several times. A certain amount of almost pure pregnane-3,6,20-trione-5-01was easily separated after the oxidation. The yield of the main product of the reaction could be increased t o about 67%. 4-Pregnene4 ,90-dione-6 (a)-ol acetate [ "6(a)-hydrozyprogesterone acetate" ] (VII). A solution of 73.6 mg. of pregnane-3,20-dione-5,6(trans)-diol 6-monoacetate (VI) in 10 cc. of alcohol-free chloroform was cooled with ice. A moderate stream of dry hydrogen chloride was passed through i t for three hours; the temperature was always kept below f4". The solution was poured into an ice-cooled N sodium carbonate solution. After shaking this mixture in a separatory funnel, the chloroform phase was washed with water and dried with sodium sulfate overnight. After the removal of the solvent, a slightly yellow resin was obtained. Attempts to obtain crystals with the aid of several solvents failed. The material was eventually freed from all solvent and dried in a vacuum desiccator to constant weight; 72.1 mg., colorless glass. The residue was subjected t o chromatographic adsorption, for which it was dissolved in 5 cc. of benzene. T o this solution 20 cc. of petroleum ether was added. A column6 of 3 g. of aluminum oxide (aluminium oxide anhydrous, standardized for chromatographic adsorption acc. t o Brockmann, E. Merck, Darmstadt) was ~~
6
~
Jena filter tube, with permanently fused-in glass filter disc, No. 15a G3.
326
MAXIMILIAN EHRENSTEIN AND THELMA 0. STEVENS
prepared in the usual way with petroleum ether. The above solution waa allowed to drip slowly through this column, and the adsorbed material was eluted with a series of appropriate solvent mixtures (see table). The solvents were then evaporated and the residues dried in a vacuum desiccator. CHROMATOGRAPHIC FRACTIONATION NO. OF FRACTION
SOLVENT
+ 20 cc. petro+ 8 cc. petro+ 7 cc. petro+ 6 cc. petro+ 4 cc. petro+ 2 cc. petro-
8
5 cc. benzene leum ether 2 cc. benzene leum ether 3 cc. benzene leum ether 4 cc. benzene leum ether 6 cc. benzene leum ether 8 cc. benzene leum ether 10 cc. benzene 10 cc. benzene
9 10 11 12
5 cc. benzene 3 cc. benzene 10 cc. ether 20 cc. ether
1 2 3 4 5 6 7
+ 5 cc. ether + 7 cc. ether
Total. . . . .. . . . . . ,. , . . . . . . . . . , . . . . . . . . .
WEIGHT OF BEBIDUE
APPEARANCE OF BEBIDUE
WQ.1
1.2
Gelatinous
0.7
Somewhat crystalline ?
1.2
Somewhat crystalline ?
2.1
Oily, trace of crystals
7.1
Oily, trace of crystals Mainly oily, with few centers of crystallization Largely crystalline Mainly oily, several centers of crystallization Largely crystalline Largely crystalline Trace of crystals Trace of crystals
15.3 14.0 7.1 16.0 1.9 0.5 0.4 67.5
After some experimenting, i t was found advisable to treat the crystalline residues with a mixture of ether (1part) and petroleum ether (2parts). Most of the resinous material went into solution, and the liquid was separated from the crystals by decantation. YIELDSOF CRYSTALLINE MATERIAL AND MELTINGPOINTS FBACTION NO.
Y.P., 'C.
YIELD, MG. ~~
7 8 9
(a) 3.7; (b) 1.6 5.7 7.4
~~
(a) 142.5-144.5"; (b) 143.5-145" 142-143.5' 144-145.5"
Because of the identical melting points all crystalline material was combined (18.4mg. = 26.4% of the theoretical yield). It was dissolved in ether and petroleum ether was added until a turbidity appeared. The separation of clusters of crystals began almost a t once. After standing overnight, the crystals (irregular-shaped stout plates) were filtered and washed with a mixture of ether and petroleum ether
INVESTIGATIONS ON STEROIDS
327
(1:3). Yield 10.3 mg., melting point 145-146". Further crops were secured from the mother liquor. [a]'b;6 89.7" (20.0 mg. in 2.0 cc. of absolute alcohol). Anal. Calc'd for ClaH~zOl:C, 74.14; H, 8.66. Found: 73.75; H, 8.48. The ultraviolet absorption curve and the reaction with tetranitromethane have been noted in theoretical part. This dehydration experiment was successfully repeated several times. Pregnane-8,6,800-trione( I X ) ? Eighty-three milligrams of 6(a)-hydroxyprogestcrone acetate (VII) was dissolved in 10.2 cc. of 1%methanolic potassium hydroxide. This solution was allowed to stand a t room temperature for about 48 hours. Then 80 cc. of water was added, and the alkalinity was reduced by passing in carbon dioxide. The methanol was removed in vacuo, and a white precipitate appeared. The solution was thoroughly extracted with freshly distilled ether and the combined ether extracts were carefully washed with water. The solution was concentrated to a small volume, omitting the usual drying with sodium sulfate. On cooling, white crystals began t o form. The crystallization was increased by allowing the solution to stand in the refrigerator for about one-half hour. The crystalline precipitate was separated by decantation and immediately recrystallized by dissolving in acetone and adding ether. Two crops of crystalline material (A), totalling 10.9 mg. and melting between 195' and 227" were secured; by recrystallization, the melting point could be raised t o 222-228'. The original ether solution was brought to dryness; the residue was & yellow resin. Three more crops of crystals (B) totalling 27.2 mg. were secured by dissolving the resin in acetone and adding ether. The melting points of these three crops of crystals (B) were much lower than those of the fractions (A), extended over a wide range, and could not be raised by repeated recrystallizations. A part of this low-melting material (B) was dissolved in absolute alcohol t o which a few drops of concentrated hydrochloric acid was added. This solution was refluxed for about 30 minutes. After working up, at least one-third of the treated material was found to have been converted into a substance melting as high as 224-227', and giving no depression of melting point when mixed with the highmelting substance (A), (m.p. 222-228", see above). An attempt was made to acetylate the substance melting at 224227'. It was dissolved in a mixture of equal parts of acetic anhydride and pyridine; this solution was heated on the water-bath for 5 hours. The product of the reaction consisted mainly of unchanged starting material. The sample selected for microanalysis and for the determination of the ultraviolet absorption spectrum had the melting point 226.5-230". The analysis showed an ash content of about 2%. The analytical figures are correspondingly corrected. Anal. Calc'd for CZlHaoOs: C, 76.31; H, 9.16. Found: C, 76.19; H, 9-10. Pregnane-dO-one-SGB)-6,6(cis)-triol 8,B-diacetate. Pregnane-20-one-3@)-5, 6(cis)triol was prepared according t o the procedure described in the preceding paper (1). The yield of pure material was 53%. Two hundred milligrams of this substance was refluxed with 2.0 cc. of acetic anhydride for 1.5hours. When the solution approached room temperature, crystals began t o separate. The acetic anhydride was decomposed by the addition of much water. The following day the crystalline precipitate was filtered, washed with water and dried. Yield, 215 mg. of crystals melting at 248-251'. This substance was recrystallized from 95% alcohol, from which i t separated in scales melting at 251.5252'; [all:' 56.6" (20.0 mg. in 2.0 cc. of acetone). Anal. Calc'd for ClsHaaOs: C, 69.08, H, 8.82. Found: C, 68.93, 68.71; H, 8.76, 8.90.
+
+
328
MAXIMILIAN EHRENSTEIN AND THELMA 0. STEVENS SUMMARY
1. Pregnane-20-one-3(8)-5,6(trans)-triol (11) was converted into its 3,6-diacetate (IV). This substance was partially saponified to pregnane20-one-3(8)-5, 6(trans)-triol 6-monoacetate (V) which was then oxidized to pregnane-3,20-dione-5, 6(trans)-diol6-monoacetate (VI). The latter compound wm dehydrated to 4-pregnene-3,20-dione-6(~~)-01 acetate [6((r)hydroxyprogesterone acetate] (VII). Saponification of this substance did not yield the free 6(a)-hydroxyprogesterone (VIII), but an isomer to which must probably be assigned the structure of pregnane-3,6,20trione (IX). 2. Pregnane-20-one-3(8)-5,6(cis)-triol (111) was converted into its 3,6-diacetate. 3. The acetate of 6(a)-hydroxyprogesterone (VII) manifests distinct progestational activity, and possibly slight adrenal cortical activity. PHILADELPHIA, PA. REFERENCES (1) EHRENSTEIN, J. Org. Chem., 4, 506 (1939). (2) VERZXR, “Die Funktion der Nebennierenrinde,” Benno Schwabe & Co., Verlag, Basel, 1939, p. 37. (3) STEIGER AND REICHSTEIN, Heiv. Chim.Acta, 20, 1164 (1937). AND v. E m , Helv. Chim. Acta, 21, 1197 (1938). (4) REICHSTEIN “Die Funktion der Nebennierenrinde,” pp. 37,210. (5) VERZXR, (6) LONG,KATZIN, AND FRY,Endocrinology, 26,309 (1940). (7) INGLE,Endocrinology, 26, 472 (1940). (8) EHRHART, RUSCHIG, AND AUMULLER, Angew. Chem., 62, 363, (1939). See also: BOCKMUHL, EHRHART, RUSCHIG, AND AUM~~LLER, U. S. Patent 2,142,170 (to Winthrop Chemicals Co.), Chem. Abstr., 33,3078 (1939);Chem. Zentr., 1939, 11, 170. (9) PFIFFNER, J . Biol. Chem., 132, 461 (1940). (10) RUZICKA, GATZI,AND REICHSTEIN, Helv. Chim. Acta, 22, 626 (1939). STAVELY, J . Am. Chem. Soc., 62,489 (1940). (11) EHRHART, RUSCHIG, AND AUMULLER, Ber., 72, 2035 (1939). AND REICHSTEIN, Helv. Chim. Acta, 21, 175 (1938). (12) See for instance: STEIGER (13) HEILBRON, JONES,AND SPRING, J . Chem. SOC.,1937, 801. J. Chem. SOC.,1939, 1078. (14) ELLISAND PETROW,
