Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J7/00—Normal steroids containing carbon, hydrogen, halogen or oxygen substituted in position 17 beta by a chain of two carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J21/00—Normal steroids containing carbon, hydrogen, halogen or oxygen having an oxygen-containing hetero ring spiro-condensed with the cyclopenta(a)hydrophenanthrene skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07J—STEROIDS
  • C07J5/00—Normal steroids containing carbon, hydrogen, halogen or oxygen, substituted in position 17 beta by a chain of two carbon atoms, e.g. pregnane and substituted in position 21 by only one singly bound oxygen atom, i.e. only one oxygen bound to position 21 by a single bond

Definitions

• the present invention relates generally to steroids and, in particular, to methods for the preparation of 17 -acetoxy-l l ⁇ -(4-N,N-dimethylaminophenyl)-19-norpregna-4,9- diene-3,20-dione, intermediates useful in those methods, and methods for the preparation of such intermediates.
• a method for the preparation of the 19-norprogesterone described in the '262 is reproduced in Figure 1.
• This method begins by converting the dienone, 17 ⁇ -hydroxy-19- norpregna-4,9-diene-3,20-dione II, to a bis-ketal compound A via a reaction with ethylene glycol and triethylorthoformate in the presence of an acid catalyst.
• the bis-ketal compound A is then epoxidized using hexafluoroacetone/H 2 O 2 in the presence of sodium phosphate dibasic to provide the epoxide compound of formula B.
• the epoxide then undergoes conjugate ring-opening using a copper (I)-catalyzed Grignard reagent generated by the reaction of 4-bromo-N,N-dimethylaniline with magnesium in the presence of copper (I) to provide compound C.
• a hydrolysis/dehydration procedure is then used to convert compound C to the compound D, which is acetylated to produce the desired 19- norprogesterone of formula I (indicated as compound I in Figure 1).
• the foregoing procedure can be used to prepare the 19-norprogesterone of formula I, certain drawbacks are inherent in the procedure.
• the foregoing procedure includes processing steps, which are not readily amenable to the preparation of commercial quantities of the desired 19-norprogesterone.
• the method described in the '262 patent requires the formation of a bis-ketal compound which does not proceed to completion (only 60% yield at best) and involves extensive chromatographic separation in order to purify the bis-ketal product. Deprotection of the bis-ketal is also not quantitative. As a result of these shortcomings, the overall yield provided by this known process is relatively low.
• the invention provides a method for the preparation of the 19-norprogesterone of formula I and its intermediates. The method is more efficient than currently available methods, providing such compounds in relatively large and highly pure quantities.
• the present invention comprises acetylating the hydroxyl group in the compound of formula II
• VI deketalizing and dehydrating the compound of formula VI to provide the compound of formula I.
• one is able to obtain the desired 19- norprogesterone in a relatively high yield and at a high purity level.
• another aspect of the present invention provides methods for the preparation of several of the intermediates useful for the preparation of the 19-norprogesterone of formula I, e.g., intermediates II, III, IV, V, and VI, as well as methods of converting one intermediate to another.
• Figure 1 sets forth a known method for the preparation of the 19- norprogesterone of formula I.
• Figure 2 sets forth a method for the preparation of the 19-norprogesterone of formula I in accordance with an embodiment of the present invention.
• the present invention provides a method for preparing the compound of formula I (i.e., 17 -acetoxy-l l ⁇ -(4-N,N-dimethylaminophenyl)-19-norpregna-4,9-diene-3,20- dione).
• the starting material used in the method of the present invention is a compound of formula II (i.e., 17 ⁇ -hydroxy-19-norpregna-4,9-diene-3,20-dione).
• the 17-hydroxyl group in the compound of formula II is protected.
• the 17-hydroxyl group is acetylated to form a compound of formula III (i.e., 17 ⁇ -acetoxy-19-norpregna-4,9-diene-3,20-dione).
• acetylating agents can be utilized.
• acetic acid e.g., acetic anhydride
• anhydrides e.g., acetic anhydride
• a mixed anhydride of acetic acid combinations thereof, and the like
• a mixed anhydride procedure employing a trifluoroacetic anhydride/acetic acid mixture is used.
• p-Toluene sulfonic acid can be used as a catalyst.
• the molar amount of trifluoroacetic anhydride is approximately equal to, or greater than, the molar amount of the acetic acid and the molar amount of the compound of formula II.
• the molar amounts of the trifluoroacetic anhydride and acetic acid are up to about 20 times or more than the molar amount of the compound of formula II.
• solvents suitable for the acetylation reaction include, but are not limited to, dichloromethane, tetrahydrofuran (THF), diethyl ether, acetonitrile, dioxane, and the like, with dichloromethane being a preferred solvent.
• the reactants are advantageously maintained at a temperature of from about -10°C to about 30°C, and most preferably at a temperature of about 0°C.
• the reaction mixture is cooled and neutralized via dropwise addition of base (e.g., ammonium hydroxide, sodium carbonate, sodium bicarbonate, or another suitable base).
• base e.g., ammonium hydroxide, sodium carbonate, sodium bicarbonate, or another suitable base.
• the mixture is neutralized with an ammonium hydroxide solution.
• the mixture is then diluted with water and extracted with an organic solvent (e.g., dichloromethane).
• an organic solvent e.g., dichloromethane
• the 3-carbonyl group of that compound is ketalized to provide the compound of formula IV (i.e., 3,3-ethylenedioxy-17 ⁇ - acetoxy-19-norpregna-5(10),9(l l)-diene-20-one).
• the ketalization step can be conducted in any suitable manner, but is preferably undertaken by reacting the compound of formula III with a diol in the presence of an acid.
• Any suitable acid may be used in the foregoing reaction to catalyze the formation of the ketal.
• Suitable acids for this purpose include organic and inorganic acids.
• an organic acid is used to catalyze ketal formation.
• an organic acid is preferably selected from sulfur-based organic acids, e.g., methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, and naphthalenesulfonic acid, with toluenesulfonic acid being the most preferred.
• any suitable diol may be used for the formation of the ketal.
• the diol can be provided in excess with respect to the carbonyl group(s) being ketalized, so as to favor the formation of the ketal.
• the diol used in the ketalization step is ethylene glycol.
• Suitable water scavengers can be used in the foregoing reaction to remove chemically the water from the ketalization reaction and drive the reaction to completion.
• Suitable water scavengers include, for example, orthoesters, particularly orthoformate esters, which are advantageous in that they provide high yields.
• Preferred orthoformate esters include triisobutyl orthoformate, triisopropyl orthoformate, and triethyl orthoformate, with triethyl orthoformate being most preferred.
• the ketalization reaction preferably is conducted in the presence of a solvent, which is preferably a halogenated solvent.
• a solvent which is preferably a halogenated solvent.
• Suitable halogenated solvents include chloroform, dichloromethane, dichloroethane, and trichloroethane, with a preferred solvent being dichloromethane.
• Compound of formula IV can be purified using any suitable purification method, but is preferably purified by crystallization from ethyl acetate. Quantitative yields of compound of formula IV have been obtained by recrystallization of the ketalization product from boiling ethyl acetate. The high yield for mono-ketalization is in marked contrast to the yield of 60% or less that was achieved for bis-ketalization following the method of the '262 patent. In addition, isolation of pure mono-ketal intermediate can be achieved efficiently without the need for laborious chromatography.
• the compound of formula IV is then epoxidized to form the 9, 11 -unsaturated 5 ⁇ ,10 ⁇ -epoxide of formula V (i.e., 3,3-ethylenedioxy-5 ⁇ ,10 ⁇ -epoxy-17 ⁇ -acetoxy-19- norpregna-9(l l)-ene-20-one).
• the epoxidation reaction can be carried out using any suitable epoxidation procedure, but is preferably accomplished by reacting the compound of formula IV with a halogenated acetone and a peroxide in the presence of an inorganic base.
• Any suitable peroxide, or peracid can be used in this reaction.
• suitable peroxides include hydrogen peroxide, sodium peroxide, potassium peroxide, benzoyl peroxide, and acetyl peroxide, with the preferred peroxide being aqueous hydrogen peroxide, most preferably 30 wt.% hydrogen peroxide in water.
• the halogenated acetone can be any suitable acetone that provides the desired results.
• a hexahalogenated acetone is used, e.g., hexafluoroacetone, hexachloroacetone, or hexabromoacetone, with hexafluoroacetone being preferred.
• the reaction is preferably carried out in the presence of an inorganic base, which is most preferably a phosphate base or a carbonate (or bicarbonate) base.
• suitable phosphate bases include di- and tri-basic sodium and potassium phosphate.
• Suitable carbonate bases include sodium and potassium carbonate, and sodium and potassium bicarbonate.
• the epoxidation reaction is carried out in the presence of dibasic sodium phosphate.
• dibasic sodium phosphate in combination with the 30 wt.% hydrogen peroxide and hexafluoroacetone.
• the epoxidation reaction is further advantageously conducted in the presence of a solvent, which is preferably a halogenated solvent.
• Suitable halogenated solvents include chloroform, dichloromethane, dichloroethane, and trichloroethane, with the most preferred solvent being dichloromethane.
• the compound of formula V can be crystallized using an ether, e.g., diethyl ether, isopropyl ether, isobutyl ether, and n-butyl ether, with diethyl ether being preferred.
• the stereoselectivity of the 5 ,10 ⁇ -epoxide versus the 5 ⁇ ,10 ⁇ -epoxide was 7:1 using the 17 ⁇ -acetoxy intermediate (compound IV) in accordance with the present invention.
• a 3:1 mixture of the 5 ⁇ ,10 ⁇ -epoxide and 5 ⁇ ,10 ⁇ -epoxide was obtained using the bis-ketal (compound A of Fig. 1) according to the method of the '262 patent. Because of the advantageously high -epoxide to ⁇ -epoxide ratio obtained in accordance with the present invention, isolation of the desired 5 ⁇ ,10 ⁇ -epoxide product via chromatography was not necessary.
• the epoxide in the compound of formula VI undergoes a conjugate ring-opening reaction, and a N,N-dimethylaminophenyl functional group may be substituted, preferably in the axial position, of C ⁇ , to provide the compound of formula VI (i.e., 3,3-ethylenedioxy-5 ⁇ -hydroxy-17 ⁇ -acetoxy-ll ⁇ -4-(N,N- dimethylaminophenyl)- 19-norpregna-9-ene-20-one).
• the foregoing reaction preferably is performed by reacting the compound of formula V with a Grignard reagent prepared from the reaction of j9-bromo-N,N-dimethylaniline and magnesium in the presence of a cuprous halide (e.g., cuprous chloride).
• a cuprous halide e.g., cuprous chloride
• the reaction is further advantageously conducted in the presence of a solvent.
• the solvent can be dry THF or an ether, such as diethyl ether, with a preferred solvent being dry THF.
• the reaction may be carried out with about a two-fold excess of Grignard reagent relative to the epoxide in accordance with the present invention.
• nearly five-fold excess of Grignard reagent is used in the process described in the '262 patent.
• Compound of formula VI is further advantageously obtained in crystalline form by crystallization from an ether, preferably, diethyl ether.
• the compound of formula VI is then deketalized and dehydrated to provide the compound of formula I.
• the foregoing conversion of the compound of formula VI to the compound of formula I preferably is performed by reaction with an acid.
• the acid can serve the dual function of hydrolyzing the ketal group (i.e., deketalization) and removing the hydroxyl at C 5 position (i.e., dehydration).
• Any suitable acid that functions to hydrolyze the ketal group can be used in accordance with the present invention.
• Suitable acids include, for example, acetic acid, sulfuric acid, hydrochloric acid, and phosphoric acid.
• the acid is acetic acid.
• the deketalization reaction is preferably conducted in the presence of a solvent.
• the solvent can be any suitable solvent, for example THF, diethyl ether, acetonitrile, dioxane, dichloromethane, and the like, with a preferred solvent being THF.
• the deketalization reaction advantageously can be carried out under reflux conditions.
• the compound of formula I can be crystallized from acetone/hexane in high yield (e.g., 82 % yield) and in high purity.
• the present inventive method for preparing the compound of formula IV from the compound of formula II was surprisingly found to provide a greater yield than known methods requiring bis-ketalization. Although not wishing to be bound by any particular theory, it is believed that the C20 ketone group is sterically hindered by the presence of the 17 -acetoxy group, thus rendering it substantially unreactive toward other chemical reagents. This discovery led to the elimination of the low yield bis-ketalization step used in conventional methods.
• the present inventive method provides a much greater yield of the final product of formula I as compared to yields obtained using conventional methods, and also avoids the need for laborious chromatographic separation, making the present inventive method more readily amenable to scale-up.
• an overall yield of the compound of formula I of about 20% or more starting from compound of formula II. This is contrasted with known methods, such as the method described in the '262 patent which provides an overall yield of about 12%.
• a preferred embodiment of the present inventive reaction scheme is depicted in Figure 2.
• the present invention further allows one to prepare any of the intermediates described herein starting from the compound of formula II, or any other preceding intermediate, as well as the compound of formula I starting from any of the aforesaid.
• the following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.
• the reaction mixture was cooled in an ice bath and neutralized by the dropwise addition of concentrated (29.5%) ammonium hydroxide solution (862 mL, 13.46 mol) over a period of about an hour.
• the reaction mixture was diluted with water (500 mL) and extracted with CH 2 C1 2 (3x). The organic fractions were washed with saturated sodium bicarbonate solution (lx), water (lx), and brine (lx), then filtered through anhydrous sodium sulfate, combined and concentrated in vacuo. Crystallization of the residue from acetone/hexanes gave 12.0 g of the purified product (II) in two crops as a pale yellow solid in 77% yield; m.p. 203-205 °C.
• a dry 250 mL round bottom flask was equipped with a reflux condenser, a stirring bar and rubber septum. Magnesium (342 mg, 14.1 mmol), was added and the entire assembly was dried with a heat gun under a stream of nitrogen. The apparatus was allowed to cool slightly and one crystal of iodine was added. After cooling completely, dry THF (13 mL; Na/benzophenone) was added, followed by one drop of 1,2-dibromoethane. A solution of 4-bromo-N,N-dimethylaniline (2.56 g, 12.8 mmol) in dry THF (7 mL) was added via transfer needle and rinsed in with an additional 6 mL of THF.

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• 2004
  • 2004-02-13 US US10/542,580 patent/US20060111577A1/en not_active Abandoned
  • 2004-02-13 AU AU2004217988A patent/AU2004217988C1/en not_active Ceased
  • 2004-02-13 JP JP2006508726A patent/JP2006519255A/ja active Pending
  • 2004-02-13 EP EP04711161A patent/EP1613640A4/en not_active Withdrawn
  • 2004-02-13 CA CA2516319A patent/CA2516319C/en not_active Expired - Fee Related
  • 2004-02-13 WO PCT/US2004/004246 patent/WO2004078709A2/en not_active Ceased

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