The invention described herein was made in the course of work under Grant No. CHE-83-00253 from the National Science Foundation. The U.S. Government has certain rights in this invention.

This application is a continuation-in-part of U.S. Serial No. 055,139, filed May 28, 1987, the contents of which are hereby incorporated by reference.

Background of the Invention

Throughout this application various additional publica¬ tions are referenced and citations are provided in parentheses for them. The disclosures of these publi- cations in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertainsc

Steroids, particularly 5-alpha-steroids and 4,5 dehydro analogs thereof, are well known chemical compounds which exhibit significant physiological activity. Steroids having a keto group at the 3-position are especially important in this regard. 5-alpha-steroids of the androstane series are presently utilized as anabolic agents and fertility control drugs and as intermediates in the preparation of such agents and drugs. Certain steroids of the pregnane series are particularly effective as anti-inflammatory agents and

as cardenolides. Steroids of the cholestane series, such as cholesterol and sitosterols, particularly beta- sitosterol, are naturally occurring compounds and are already useful or are potentially useful as starting materials for the commercial preparation of therapeuti- cally important steroids.

Steroids which include a vide variety of substituent groups are useful therapeutically. For example, 9- alpha-f uoro substituted steroids and 16-a pha-methy substituted steroids, such as 9-alpha-fluoropred- niselone, triamcinolone, 16-alpha-methylprednisolone, and dβxamethasone, exhibit high glucocorticoid and anti-inflammatory activity. (U.S. Patent Nos. 2,864,836 [1958] and 2,838,547 [1958]; and generally L.F. Fieser and M_ Fieser, STEROIDS, Van Nostrand Reinhold Co. [1959], pp. 682-696). In the androstane series, 11-beta-hydroxy substituted compounds which have antiandrogenie and gonadetropic activity have been described (U.S. Patent Nos. 2,731,479 [1956] and 2,702,811 [1955]). These skilled in the art to which this invention pertains will know other compounds characterized by the basic steroid nucleus which may be utilized either directly as, or indirectly to provide, useful compounds.

Synthetic procedures are known for the. production of useful steroids from naturally occurring steroids _β Oiosgenin is an important source of steroids of the pregnane series such as prednisolone and its numerous derivatives. Because of their ready availability from plant sources, sitosterols, particularly beta- sitosterol, have been often studied as commercially useful starting materials for the synthesis of 5-alpha- steroids of the pregnane and androstane series. Howev-

er such approaches have not met with significant suc¬ cess, principally because of difficulties in removing the side chain, except in low yield, and in introducing functional groups into a molecule devoid of such groups other than the 3-beta-hydroxyl group and the double bond at the 5,6 position.

Available methods for removing the side chain include chemical and microbiological oxidation. Unfortunately, the yields from these procedures are unacceptably low. Moreover, a significant capital investment is required to construct, operate and maintain a plant to carry out microbiological oxidation.

Methods have previously been developed to direct chlo- rination to various tertiary positions on steroids by the use of attached iodine- or sulfur- containing tem¬ plates. The resulting chlorinated steroids may then be used as precusors to introduce double bonds or other functional groups at the chlorinated site. (Breslow, R., Corcoran, R.J., and Snider, B.B., J. Am. Chem. Soc. 1974, 96. 6791; Breslow, R., Corcoran, R.J., Snider, B.B., Doll, R.J., Khanna, P_L. and Kaleya, R., J. Am. Chem. See. 1977, 99.905; Breslow, R_, Wife, R.L. and Prβzant, D., Tetrahedron Letters 1976, £3:1925; and Breslow, R. and Heyer, D., J. Am. Chem. Soc. 1982, 104.2045, .

In Breslow et al_, U.S. Patent No. 4,252,719 (1981), a method for the selective removal of tertiary hydrogen atoms on steroid nuclei and side chains is described. This method requires that the steroid be esterified by iodo aryl substituted acids, acid anhydrides, or acid chlorides, thereby covalently binding a iodo aryl template compound being covalently bound to the

steroid. Breslow et al., U.S. Patent No. 4,323,512 (1982) , discloses an improvement on this method so as to directly esterify the 17-alpha-hydroxy group of a steroid to form the covalently bound iodo aryl template compound.

Once the template is attached, the steroid esters is then chlorinated under free radical generating condi¬ tions in order to selectively replace the hydrogen with a chlorine. The chlorinated steroid ester is there¬ after dehydrochlorinated to produce the unsaturated steroid.

An iodo aryl template which halogenates three steroid substrates has also been described. Breslow, R. and Heyer, D_, J. Am. Chem. Soc. 1982, 104,2045.

The present invention provides a method for substitut¬ ing a chlorine atom for a hydrogen atom on a steroid nucleus by using a template compound comprising a nitrogen-containing ring or a substituted or fused ring derivative thereof- The template compound of the present invention possesses several advantages over the above-described templates containing an iodoaryl or sulfur aryl group. For example, nicotinic acid, which may be used as a starting material for the template compound, is part of the natural vitamin niacin, and therefore, harmless if ingested as a contaminate in the end-resulting medicinal products. Moreover, the geometry of the chlorine atom adduct of the nitrogen- containing ring compound is expected to be different than the geometry of the chlorine atom adduct of iodo aryl compounds. Therefore, selectivities of the two adducts are expected to .be different. The nitrogen- containing ring compounds of the present invention are

- 5 -

also basic, while the iodo and sulfur-containing templates are not. Thus, the templates of the present invention may be removed and recovered by extraction with acid, while the previously known templates cannot. Additionally, the derivatives for the templates of the present invention are generally more available than are iodo-benzene derivatives, thereby making nitrogen- containing ring templates more economical.

- 6 -

Summary of the Invention

This invention concerns a method of substituting a chlorine atom for a predetermined hydrogen atom located within an organic compound which comprises contacting the organic compound containing the predetermined hydrogen atom with an esterifying agent comprising a nitrogen-containing ring or a substituted or fused ring derivative of a- nitrogen-containing ring so as to produce an ester and treating the ester with a chlorinating agent so as to substitute the chlorine atom for the predetermined hydrogen atom. The ester comprises the nitrogen-containing ring or the substituted or fused ring derivative of the nitrogen- containing ring so positioned within the ester with respect to the predetermined hydrogen atom that a chlorine atom attached to the nitrogen atom of the nitrogen-containing ring or substituted or fused ring derivative of the nitrogen-containing ring reacts with the predetermined hydrogen atom..

Another aspect of the invention is a method for converting a predetermined single bond between a carbon atom and another atom in an organic compound into a double bond between the carbon atom and the other atom which comprises substituting a chlorine atom for a predetermined hydrogen atom bound to the carbon atom or the other atom of the organic compound according to the method of this invention so as to produce a chlorine- containing compound and then treating the chlorine- containing compound so as to eliminate the chlorine atom from the compound and form the double bond.

The invention also provides a method for producing a compound in the betamethasone, dexamethasone,

triamcinolone or prodnisolone family which comprises converting a predetermined single bond between carbon-9 and carbon-11 in a steroid into a double bond by the method of this invention.

The invention further concerns a compound having the structure:

or

wherein R is a steroid of the cholestane, androstane or pregnane series and either Z or Z. is a nitrogen atom and the other is a carbon atom.

Detailed Description of the Invention

This invention concerns a method of substituting a chlorine atom for a predetermined hydrogen atom located within an organic compound which comprises contacting the organic compound containing the predetermined hydrogen atom with an esterifying agent comprising a nitrogen-containing ring or a substituted or fused ring derivative of a nitrogen-containing ring so as to produce an ester and treating the ester with a chlorinating agent so as to substitute a chlorine atom for the predetermined hydrogen atom. The ester comprises the nitrogen-containing ring or the substituted or fused ring derivative of the nitrogen- containing ring so positioned within the ester with respect to the predetermined hydrogen atom that a chlorine atom attached to the nitrogen atom of the nitrogen-containing ring or the substituted or fused ring derivative of the nitrogen-containing ring reacts with the predetermined hydrogen atom.

Essentially any organic compound may be used in the practice of the subject invention. Merely by way of example suitable organic compounds include aromatic compounds, including benzyl, naphthyl, anthryl, and steryl compounds, and aliphatic compounds, including alkyl, alkenyl and alkynyl compounds. Presently, the preferred organic compound is one which contains between about 10 carbon atoms and 50 carbon atoms. In accordance with the presently preferred embodiments of the invention, the organic compound is a steroid, particularly a steroid of the pregnane, androstane, or cholestane series comprising a hydroxyl group. In the most preferred embodiments, the steroid is a cholestane steroid comprising a 3-alpha-hydroxyl group, a pregnane

steroid comprising a 17-alpha-hydroxyl group, or a cortexolone steroid. The steroid may also comprise a methyl group at carbon-3 or carbon-16 in the alpha or beta position, preferably at carbon-16 in the alpha position.

Although the method is suitable for substituting a chlorine atom for any predetermined hydrogen atom on the organic compound, the method is particularly useful for a predetermined hydrogen atom attached to a steroid at carbon-6, -9, -14, -17 or -20 position, especially a hydrogen atom at carbon-9 or carbon-14 position.

In the practice of this invention, suitable esterifying agents include compounds comprising a nitrogen- containing ring such as a pyridine, oxazole, thiazole, imidazole, pyrazole, isoxale, pyri idine or quinoline ring or a substituted or fused ring derivative thereof. Particularly useful esterifying agents are pyridine-- derived carboxylic acids, such as acids comprising a nicotinate or isonicotinate moiety, or imidazole containing compounds.

The contacting of the organic compound and the esterifying agent may be effected in the presence of an organic solvent, such as dimethoxyethane, to form a mixture. Contacting may also comprise heating, quenching or extracting the mixture. In the preferred embodiments, the contacting is effected in dimethoxyethane and the mixture is heated, quenched in ammonium chloride, and extracted with methylene chloride.

In certain embodiments of the invention, the organic compound is a steroid which is contacted with the

esterifying agent so as to produce the ester at the 3- alpha, 5-alpha, 6-beta, 7-alpha or 17-alpha position of the steroid. Presently an ester produced at the 3- alpha or 17-alpha position of the steroid is preferred.

In preferred embodiments of the invention the ester is a nicotinic acid steroid ester or a isonicotinic acid steroid ester or a derivative thereof. Especially preferred steroid esters are 3-alpha-cholestanyl nicotinate, 3-alpha-cholestanyl isonicotinate, 17- alpha-cortexolone nicotinate, 17 alpha-cortexolone isonicotinate, 16-alpha-methylcortexolone-17-alpha- nicotinate, or 16-alpha-methylcortexolone-17-alpha- isonicotinate.

Suitable chlorinating agents includes those capable of substituting a chlorine atom for a hydrogen atom. Preferably, the chlorinating agent is selected from the group consisting of molecular chlorine, phenyliodine- dichloride or sulfuryl chloride, particularly useful is phenyliodinedichloride.

The treating of the ester typically is effected in solutions containing the ester and the chlorinating agent and an organic solvent, such as methylene chloride (CH.Cl _^ ) or methylene chloride/acetonitrile

(CH ₂ C1 ₂ /CH ₃ CN) . In certain embodiments, treating further comprises degassing the solution with an inert gas such as Argon or separating the organic compound with the chlorine atom substituted for the predetermined hydrogen atom by column chromatography or crystallization. In other embodiments, treating further comprises irradiating the solution or contacting the solution with a scavenger to neutralize the removed hydrogen atom, e.g. contacting with

potassium acetate (KOAc) , epoxybutane, or aqueous sodium bicarbonate (NaHC0 ₃ ) to neutralize hydrogen chloride (HC1) .

Another aspect of the invention is a method for converting a predetermined single bond between a carbon atom and another ^' atom in an organic compound into a double bond between the carbon atom and the other atom which comprises substituting a chlorine atom for a predetermined hydrogen atom bound to the-carbon atom or the other atom of the organic compound according to the method of this invention so as to produce a chlorine- containing compound and then treating the chlorine¬ containing compound so as to eliminate the chlorine atom from the compound and form the double bond.

Treating is typically effected by dehydrochlorination, preferably with KOH, AgBF. or AgNO. in an organic solvent. In the preferred embodiments, the other atom is a carbon atom and the organic compound is a steroid of the cholestane, androstane or pregnane series and the predetermined single bond is between carbon-9 and carbon-11 in the steroid.

The invention also provides a method for producing a compound in the betamethasone, dexamethasone, triamcinolone or prednisolone family which comprises converting a predetermined single bond between carbon-9 and carbon-11 in a steroid into a double bond by the method of this invention.

The invention also concerns a compound having the structure:

- 12 -

wherein R is a steroid moiety of the cholestane, androstane or pregnane series and either Z or Z- is a nitrogen atom and the other is a carbon atom. In certain embodiments, the compound also comprises a chlorine atom attached to the nitrogen atom of the pyridine ring or the imidazole ring. Preferably, the group having the structure:

is attached to the steroid moiety at the 3-alpha or 17- alpha position and the steroid moiety is a cholesterol, cortexolone, or methylcortexolone moiety. Especially preferred are compounds having the structures:

CI^OR,

wherein Z and 2. are the same as defined previously; X is a hydrogen or chlorine atom; Y is a hydrogen atom or a methyl group; R. is a hydrogen atom or an acetate group; and the dotted lines (....) represent bonds which may be present or absent.

In the most preferred embodiments, the compounds have the structure:

CH _j OAc

wherein Z, Z _~ , X and Y are the same as defined previously and the dotted line (....) represents a bond which may be present or absent.

Certain embodiments of this invention are exemplified in the Examples which follow. The Examples are set forth to aid in the understanding of the invention but are not intended to, and should not be construed to, limit in any way the invention as set forth in the claims which follow thereafter.

EXAMPLE 1

On 15 min. irradiation with 1.2 eqiuv. phenyliodinedichloride (PhlCl,) and 6 equiv. 1,2- epoxybutane, under conditions previously described (Maitra, U. , Breslow, R. , Tetrahedron Letters, 1986, 27.3087-90), 3-alpha-cholestanyl nicotinate (1) at 20 mM was quantitatively chlorinated to the 9-chloro derivative 2 , contaminated by the 14-chloro derivative 3_. The mixture was analyzed by hydrolysis/dehydro- chlorination with KOH to form the 9(11) olefin (92% isolated yield) and the Δ14 olefin (3% yield), respectively. With the isonicotinate ester 4. the changed geometry led to 44% recovered starting materi¬ al, 37% 9(11) olefin, 14% Δ14 olefin, and 5% of a prod¬ uct formed by double chlorination.

- 16 -

EXAMPLE 2

Irradiation of jS (3 mM) with 1.5 equiv. PhlCl, and 5 equiv. finely powdered K, CO in CH ₂ Cl ₂ for 30 min. produced the 9-chloro derivative 8_ in greater than 98% yield. This was dehydrochlorinated to the 9(11) olefin with AgBF. in acetone, and the product was converted by hydrolysis (K-CO. in MeOH) and reaeetyla ien to the 1-acetate whose NMR spectrum was identical with the published NMR spectrum (Zomer, B., Wynberg, H_ , Drayer, N.M., Steroids 1984, 44"293-300). In a similar fashion the corresponding 16-alpha-methyl steroid 2 ^was converted to the chloro derivative Ig and the 9(11) olefin 11 which was identical with an authentic sample. When the reaction of jS was performed at a higher concentration (21 mM) , a side reaction resulting in allylic chlorination competed with the template- directed process and led to a Is ratio of carbon-6 to

EXAMPLE 3

To a 17 mM solution of 3-alpha-cholestanyl isonicotinate in CH ₂ C1 ₂ /CH ₃ CN (in a 14:1 volume ratio) were added 1.14 equivalents of freshly recrystallized phenyliodinedichloride and 5 equivalents potassium acetate (undissolved) . The mixture was degassed with Argon, irradiated for 10 min. at 0*C with a 275 W sunlamp from 20 cm distance, then quenched with an excess of lθ%(w/v) aqueous NaHSO. solution and washed with water and then brine. The solvent was removed, an excess of 6%(w/v)K0H in CH ₃ OH/dioxane/H ₂ 0 (15/4/1(v/v/v)) was added and this mixture was refluxed for 2 hours. The solvent was removed in vacuo, the residue taken up in ether/water, the organic layer washed with water and neutralized with very dilute HC1- solution and NaHCO. solution. After drying over Na ₂ SO. the solvent was removed in vacuo. NMR in CHC1 ₃ showed the following product distribution: 44% recovered 3- alpha-cholestanol, 37% Δ9(ll)-3-alpha-cholestenol, and 14% Δ14-3-alpha-cholestenol.

EXAMPLE 4

200 mg of 3-alpha-cholestanyl nicotinate (0.4 moles) and 130 mg of iodobenzenedichloride were dissolved in 19 ml of dichloromethane. 200 ml of epoxybutane (2.3 mmoles) was added as a hydrogen chloride scavenger and the solution was irradiated with, a sunlamp for 10 minutes_

9-chloro-3.-alpha-cholestanyl nicotinate was isolated by evaporating the solvent and was purified on a silica column. Without purification 9-chloro-3-alpha- cholestanyl nicotinate was converted to Δ9(ll)-3-alpha- cholestenol by refluxing in a solution of 5 ml of 6% potassium hydroxide in methanolsdioxane:water (600:160:40 volume ratio) for 90 minutes. The solvent was removed by evaporation and 145 mg of steroidal products were isolated by extraction with diethylether. ^' The mixture consisted of 95% Δ9(ll)-3- alpha-cholestenol, 3% Δ14-3-alpha-cholestenol and less than 1.5% 3-alpha-cholestanole

- 19 -

EXAMPLE 5

The 17-nicotinate JL2 (lOOmg, 0.21 mmole, 1.0 equiv.) was dissolved in 70 ml dry CH ₂ C1 ₂ . Finely powdered K ₂ CO.(146 g., 1.1 mmol., 5.0 equiv.) was added. Phenyl-iodine dichloride (87 mg. 0.32 mmol. l.Seg.) was added as a solid. . The mixture was irradiated with a 275 W sunlamp at a distance of 15cm. The solution was maintained at 25 ^β C with a water bath.

At 1/2 hr,, the above solution was poured into 1/2 vol¬ ume 10% NaHSO_(aq) . The aqueous phase was extracted four times with equal volume of CH-Cl... The combined extracts were dried over Na^SO., filtered, and reduced in vacuo.

The crude 9-alpha-chloride 13 was treated with AgBF as described in Example 6. The crude product was greater than 97% pure. A trace of the 6-chloro compound was detectable.

12

EXAMPLE 6

The 9-alpha-chloride _, 13, as obtained from the chlorination reaction without purification, (0.21 mmol. assumed, 1.0 equiv.) was dissolved in 3 ml acetone. Solid AgBF (55 mg., 0.28 mmol., 1.3 equiv.) was added. The solution was stirred 12 hrs. The resulting suspension was diluted with NH.Cl (sat'd aq.) and CH ₂ 1 ₂ . The phases were separated, and the aqueous phase was extracted five times with CH.Cl-. The combined extracts were dried over Na,S0 ₄ , filtered, and reduced in vacuo. Material recovery was approximately 100%.

Chromatography on Si0 ₂ with CH _^ Cl,: acetone (8:1) was performed. The pure Δ4,9(ll) diene 14 is recovered in 70% yield. (Material recovery from the column was equal to or less than 80%.)

_

- 21 -

EXAMPLE 7

The 17-alpha-nicotinate .12 (15 mg., 0.03 mmol., l.o equiv.) was dissolved in 10 ml. CH<,C1 ₂ . Azobisisobutyronitrile (1 mg., 0.006 mmol., 0.2 equiv.) was added, followed by sulfuryl chloride (5μl., 0.06 mmol., 2.0 equiv.).- The mixture was irradiated with a 275 W sunlamp at 15 cm. The solution was maintained at 25 ^β C with a water bath.

At 1/2 hour the above solution was poured into 1/2 volume of 10% NaHSO. (aq.) . The aqueous phase was extracted four times with equal volumes of CH ₂ C1 ₂ . The combined extracts were dried over Na 2.SO4., filtered, and reduced in vacuo. Crude mass balance was approximately 100%. The crude 9-alpha-chloro compound 13, contained about 10% unreacted starting material.

CHjOAc

I

11

- 22 -

EXAMPLE 8

291 mg. of cortexolone-21-acetate, 941 mg. of nicotinic anhydride, and 869 mg. of 4-dimethylaminopyridine were suspended in 7 ml. of 1,2-dimethoxyethane. The mixture was heated at 55*C for 31 hours, then quench with aqueous ammonium chloride (NH.Cl) and extracted with methylene chloride.

Chromatography on silica (Si0 ₂ ) afforded 358 mg. (97% yield) of the product ester 12: as a glass and a small amount of recovered starting material. ' NMR and mass spectrum of the product confirmed structure 12.

12

EXAMPLE 9

17-hydroxy steroid (1) with nicotinic anhydride (5.5 eq) , dimethylaminopyridine (DMAP) (9.5 eq) , and pyridine (QS approximately 1 M in DMAP) were heated at 90*C for 36 hrs. The reaction mixture was cooled, and reduced to a solid in vacuo. The residue was dissolved in 1 M HC1, and extracted with CH ₂ 1 ₂ . The extracts were washed with saturated aqueous NaHCO., water, and dried over Na.SO.. The solution was reduced in vacuo to an orange glass. The major product is the 17- nicotinate ester (2) , plus a minor product containing two nicotinate residues by NMR. A reaction run at 0.25 mmol scale was chromatographed (CH^Cl,:acetone 80:20, silica) to yield 76% of the desired product, identified by NMR and mass spectrum, 7.4% of the bis acylated product, and 7.5% starting material (91% material recovery) . Best yield obtained, approximately 85%, plus 15% 20-enol ester.

Photochlorinations using PhICl ₂ or SO-Cl. and AIBN as a less expensive chlorine source were performed as described in previous examples.

The 9-alpha-chloro-16-alpha-methyl steroid (3) (1.07 g, 1.98 mmol) was dissolved in acetone (ACS certified, 20 ml) with NaBF ₄ (.869 g, 7.92 mmol) and AgNo.. (.672 g, 3.96 mmol). The mixture was heated to reflux for 70 minutes. The solution was cooled and poured into 40 mis brine, 40 mis CH^Cl, and 10 mis water. The mixture was extracted 3 times with CH ₂ C1 ₂ , dried over a ₂ S0 ₄ , and reduced to an oil in vacuo. Weight recovery was 90%. The product was chromatographed on Si0 ₂ with 60:40 hexaneβ:acetone as eluent. The recovered delta 9(11) steroid (4) was 96% of the weight submitted to

- 24 -

chromatography, .865 g, 87% of the theoretical, identified by NMR and mass spectrum. The purity is approximately 93% as judged from the NMR. Of the impurities, approximately 5% is the delta 8 olefin formed in the dehydrochlorination.

The delta 9(11) diester (4) (200 mg, .398 mmol) is dissolved in 90% methanol (5 s ) The solution is cooled to 0*€ in ice and a solution of ₂ C0 ₃ (27.4 mg, .199 ol, 0.5 eq) in 90% methanol (approx. 25 ml) is added slowly. The solution turns orange. The reaction is complete in less than 2 hrs. Glacial acetic acid is added to give a pale yellow solution, which is diluted with water, and extracted three times with CH ₂ C1 ₂ . The organic extracts were washed with saturated aqueous NaHC0 ₃ , water, and dried over Na.SO., and reduced to an oil in vacuo. ^' The weight recovery was approximately 100%, as the methyl nicotinate is also recovered. The yield of the reaction as assessed from the crude spectra was greater than 90%. Comparison to authentic samples by NMR (400 MHz) shows the product to be identical to the known delta 9(11) diol (5).

- 25 -

EXAMPLE 10

1 equivalent (0.0682g, 0.42 mmol) of N,N-carbonyl di- imidazole was added to one equivalent of 3α-cholestanol (0.1633g, 0.420 mmol) in 10 ml dry distilled benzene. The solution was refluxed under argon for 6 hrs. Reaction was followed by TLC to disappearance of starting material, 3α-cholestanol_

After 6 hrs refluxing, the reaction mixture was rotovapped to dryness and loaded onto a SiO_ column. Flashed with 20% EtoAc.80% hexane. Yield - 0.194 mgs (96%)

Characterization:

H-NMR £0.6-2.0 ppm - characteristic cholestanol skeleton

£8.15 (S, 1M)

FW 482

CI-CH 4 _„ -MS M+π 483

- 26 -

EXAMPLE 11

3α cholestanylimidazolide 1 (36.5mg, 0.0757 mmol) and phenyliodine dichloride (25.0sg, 0.0908 mmol) were dissolved in methylene chloride (5.0 »!)_ The flask was flushed with Argon and sealed with a rubber septa.

The clear pale yellow solution was irradiated with a

275 watt sunlamp for 20 minutes. It was then

_ rotovapped. H-NMR indicated formation of 9 ehloro steroid.

The crude photoproduet was refluxed with KOH/MeOH dioxan for 2 hrs, cooled and extracted into ether. The ether layer was washed several times with water, then brine, dried over anhydrous soduim sulfate and rotovapped. H-NMR indicated formation of Δ9,ll-3α cholestanol 2 _, .- It was compared to an authentic sample of _.9,ll-°3β chelestanel and found to be identical with

yield: 89% Δ9,ll-3α cholestanol

11% recovered Sα-eholestanol

KOH/MeOH/dioxan ft 2 hf.