VITAMIN D3 DERIVATIVES

Abstract: Novel Vitamin D₃ derivatives of the following formula wherein R represents a hydrogen atom or a lower alkyl group. These compounds have an activity of inducing differen­ tiation of tumor cells, and would be useful for anti-­ tumor agents. On the other hand, the compounds have almost no vitamin D activity.

Description: This invention relates to Vitamin D₃ derivatives of the following formula (I) wherein R represents a hydrogen atom or a lower alkyl group. It is known that 1α 25-dihydroxy-vitamin D₃, a hormonal metabolite, is the biological active form of vitamin D₃ in intestinal calcium transport and bone calcium resorption (Merck Index, 1612: -Calcitriol) and it has recently been found that it has an anti-tumor effect against human leukemia-derived cells, etc. (unexamined Japanese patent publication No. 57-149224 or 58-206525). 22,25-dihydroxyvitamin D₃ is also a known compound, but it is known to possess neither vitamin D activity nor antivitamin D activity and is not known to have anti-tumor activity. We have found that the above formula (I) compounds induce differentiation of tumor (cancer) cells and so are useful anti-tumor agents. Unless otherwise specified, the term lower herein means a linear or branched chain of 1 to 5 carbon atoms. Hence, lower alkyl represents linear or branched alkyl of 1 to 5 carbon atoms, illustrated examples including methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl (amyl), isopentyl, tert-pentyl, neopentyl, 1-methylbutyl, 2-methylbutyl, 1,2-dimethylpropyl, 1-ethylpropyl, etc. The vitamin D₃ derivatives of the present invention have asymmetric carbon atoms (at least 3 asymmetric carbon atoms), and this invention includes all types of isomeric forms such as optical isomers based upon these asymmetric carbon atoms, and mixtures of any two or more thereof. The compounds of this invention can be synthesized by various methods. Typical synthetic can methods are shown below. Synthetic method 1 In the above reaction schemes R 1a , R 2a , R 3a and R 4a each represent a hydroxyl group which may be protected, R b represents a lower alkyl group, and R 1b and R 2b and R 3b each represent a hydroxyl group which may be protected. The above symbols have the same significances hereinafter. Practical examples of the protective group for a hydroxyl group are lower acyl groups having 1 to 5 carbon atoms such as acetyl, propionyl, pivaloyl, etc.; aromatic acyl groups such as benzoyl, p-nitrobenzoyl, etc.; lower alkoxy lower alkyl group such as methoxymethyl, ethoxymethyl, etc.; tetrahydrofuranyl and tetrahydropyranyl groups and other suitable protective groups. Preferred examples of protective group for R 1a , R 1b , R 2a , R 2b and R 3a are lower acyls, and preferred examples of protective group for R 3b and R 4a are tetrahydrofuranyl, tetrahydropyranyl, etc. In the course of manufacturing compounds (III a ) and (III b ) as above, there are produced two kinds of optical isomer according to the 22-position asymmetiic carbon atom, and each isomer can be separated by applying e.g. chromatography at a suitable step in the course of obtaining the final product from compound (III a ) or (III b ). Each step in the above Methods is explained in more detail hereinafter: Method I Step 1 Compounds (III a ) can be produced by reacting compound (II a ) with metal compound (VII a ) wherein M represents an alkali metal atom. Practical examples of "alkali metal atom" for M are lithium, sodium, potassium, etc. Examples of the solvent used for this reaction are diethyl ether, tetrahydrofuran, benzene, dioxane, dimethylsulfoxide, etc. (namely, any solvent which does not take part in the reaction). The reaction proceeds under cooling or at room temperature. An equimolar or excess amount of compound (VII a ) is preferably reacted with starting compound (II a ). For the compound (III a ), there are two isomers (high polar compound and low polar compound) according to the 22-position asymmetric carbon atom. To obtain each isomer, a conventional resolution method based upon the polarity difference is applied after the reaction of compound (II a ) with compound (VII a ). Step 2 Compound (III a ) obtained above is then reduced using a conventional reaction for reducing triple bond compounds. For example, compound (III a ) is dissolved in a solvent which does not take part in the reaction (e.g. ethyl acetate, tetrahydrofuran, diethylether, dioxane), and the reducing reaction is preferably conducted catalytically with the addition of metal catalyst such as platinum (Pt), palladium (Pd), palladium-carbon (Pd-C), rhodium (Rh), etc. The reaction is usually performed at room temperature or under heating. The reducing reaction may be applied after removing any protective group for hydroxyl in compound (III a ). Step 3 This step is for producing compound having the 7-position double bond from compound (IV a ) obtained in Step 2. Compound (IV a ) is dissolved in non-polar solvent such as carbon tetrachloride, dichloromethane, hexane, benzene, etc, and after mono-halogenating the 7-position by using N-halo organic acid amide such as N-bromoacetamide (NBA), N-bromosuccinimide (NBS), N-chlorosuccinimide (NCS), N-bromophthalimide (NBP), etc, the thus obtained compound is treated with base such as trimethylphosphite, tetra-n-butylammonium fluoride, collidine, pyridine, diaza-bicyclooctane, etc to produce compound (V a ) having the double bond. The reaction is usually performed at room temperature or under heating. Step 4 In this step, desired compound (I a ) is obtained after ultraviolet irradiation and then isomerization with heating. The ultraviolet irradiation is conducted in an organic solvent such as benzene, toluene, ethanol, methanol, diethylether, acetonitrile, etc. or a mixture thereof in an inert gas atmosphere such as nitrogen, argon gas, etc. Ultraviolet irradiation is conducted using, for example, a mercury lamp, and if necessary a filter. The irradiation is at room temperature or under ice cooling. The compound thus formed can be isolated by chromatography, etc, but is usually subjected to isomerization by heating in situ. This isomerization can be conducted by heating in an inert solvent (preferably in the same solvent as used in the ultraviolet irradiation step) at a temperature of from 20°C to 120°C, for 1-5 hours. It is preferred that this isomerization reaction be conducted in an inert (e.g. nitrogen, argon, etc) atmosphere. Process 2 Steps 1, 3, 4 and 5 are carried out in similar way to Steps 1, 2, 3 and 4 of the above Process 1, respectively. Thus, only Step 2 of Process 2 is explained below. Step 2 (alkylation) This step is for alkylating the 22-hydroxyl group of compound (III b ) which can be produced by Step 1 of Process 1. This alkylation can be conventional. For example, compound (III) can be reacted with alkyl halide such as methyl iodide, ethyl iodide, methyl bromide, ethyl bromide, propyl bromide, butyl bromide under basic conditions (e.g. the presence of K or Na hydroxide or sodium carbonate ― Method A), or with dimethylsulfonic acid, diethylsulfonic acid, etc. (that is, alkylsulfonic acid ester). The reaction temperatures may vary according to the reaction details (reactants, etc.), but usually cooling or heating is applied. The used solvent may be dimethylsulfoxide, dichloromethane, dichloroethane, ether, etc. After removing any protective group in usual manner such as hydrolysis using caustic alkali such as sodium hydroxide, potassium hydroxide, etc. or reduction using metal hydride complex such as lithium aluminum hydride, etc., the desired compound (I) is isolated and purified. The isolation and purification can be by conventional means such as crystallization, column chromatography, etc. Compounds (I) of this invention induce the differentiation of tumor cells, and so are useful as antitumor agents for neuroblastoma, nasal cancer, lung cancer, breast cancer, kidney cancer, muscle cancer, stomach cancer, myelogenous leukemia, etc. The 22S isomet of compounds (I) has particularly excellent anti-cancer effects. The effects of compounds of this invention for inducing the differentiation are shown below. Induction of cell differentiation was examined according to Mitsuzi Yoshida, et al (J. Pharm:, Dyn,, 7 , 962-968(1984)), by the method of nitroblue tetrazolium (NBT) reduction. The human promyelocytic leukemia cells (HL-60 cells) were cultured at 37°C in RPMI 1640 medium supplemented with 15% heat-inactivated fetal calf serum in an atmosphere of 5% CO₂ in air. The cells (3 × 10⁵ cells) were inoculated into 1 ml volume of culture medium containing various concentrations of vitamin D₃ derivatives and grown for 2 days at 37°C in 5% CO₂ in air. After culture, the cells were washed with 0.15 M Ca²⁺-, Mg²⁺-free Dulbecco's phosphatebuffered saline (DPBS) and resuspended in 0.5 ml of serum-free culture medium. The cell suspension was mixed with 0.5ml of DPBS containing 1 mg of NBT, in the presence of 100 ng of 12-O-tetradecanoylphorbol-13-acetate and then incubated for 20 minutes at 37°C. The number of NBT-positive and negative cells was counted microscopically among 300 cells. The activity of the compounds of this invention in inducing differentiation of the cells determined by this method is shown in the following Table. On the other hand, the present compounds have almost no vitamin D activity; they are practically ineffective against various diseases caused by calcium metabolism disorder (e.g., rickets, osteomalacia, kidney trouble, etc.), unlike usual vitamin D₃ derivatives. Medicaments containing compounds of formula (I) may be prepared by conventional methods using conventional carriers or excipients. The may for example be administered orally or parenterally. The appropriate dose is determined in each case considering factors such as the symptom, body weight, and sage of the patient. For an adult a daily total of 0.1 µg-10,000 µg is usually administered in one to several doses. Appropriate formulations are tablets, powders, granules, suppositories, capsules, alcoholic solutions, oily solutions, aqueous suspensions, etc. Such formulation medicaments can be prepared by conventional methods using conventional carriers, preservatives, stabilizing agents, etc. The invention is further illustrated by the following Examples. In the following Examples, ¹H-NMR, UV, and MS are abbreviations for hydrogen nuclear magnetic resonance spectrum, ultraviolet absorption spectrum, and mass spectrum. The stereochemistry at C-22 was determined by a method shown in the Reference Example. Example 1: (22R)-1α, 22,25-trihydroxyvitamin D₃ (I a1 ) and (22S)-1α, 22,25-trihydroxyvitamin D₃ (Ia2) (1) (22S)-1α,3β-diacetoxy-25-tetrahydropyranyloxycholest-5-en-23-yn-22-ol (III a1 ) and (22R)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (VIII a2 ). 0.61 ml of 2-methyl-3-butyn-2-ol tetrahydropyranylether was dissolved in 5 ml of tetrahydrofuran. To the solution thus obtained was added a solution of n-butyl lithium in n-hexane (1.56 M, 1.9 ml). After 5 minutes, the mixture was cooled to -78°C; and 5ml of a solution of 912 mg of 1α,3β-diacetoxy-23,24-dinorchol-5-en-22-al (II a ) in tetrahydrofuran was added to the cooled mixture. The reaction mixture was stirred for 20 minutes at -78°C. Saturated aqueous ammonium chloride was added to the mixture to finish the reaction, and the mixture was extracted with ethyl acetate, washed with water, and dried over magnesium sulfate. The solvent was distilled away, and the residue was subjected to column chromatography (n-hexane-ethyl acetate = 5: 1) for purification to give a mixture of (22S)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a1 ) and (22R)-1α,3β-diacetoxy-25-tetrahydropyranyloxycholest-5-en-23-yn-22-ol (III a2 ). From this mixture [(III a1 ) and (III a2 )], the less polar isomer (III a1 ) (212.5 mg) and the more polar isomer (III a2 ) (270 mg) were obtained by a separating method by using a column (Merck Company. Lichroprep Si 60, Size B, n-hexane-ethyl acetate = 2: 1). (III a1 ): Oily material ¹H-NMR (CDCl₃) δ ppm : 0.70 (3H, s, 18-H₃), 1.04 (3H, d, 6H z , 21-H₃) 1.09 (3H, s, 19-H₃), 1.50 (s, 26-H₃) 1.54 (s, 27-H₃), 2.03 (3H, s, C H ₃CO―) 2.06 (3H, s, C H ₃CO-), 3.52 (1H, m) 3.95 (1H, m) 4.47 (1H, d, 3.7Hz, 22-H) 4.95 (1H, m, 3-H), 5.07 (2H,m) 5.55 (1H, m, 6-H) (III a2 ): Oily material ¹H-NMR (CDCl₃) δ ppm: 0.68 (3H, s, 18-H₃), 1.08 (3H, s, 19-H₃) 1.09 (3H, d, 6Hz, 21-H₃), 1.48 (s, 26-H₃) 1.52 (s, 27-H₃), 2.03 (3H, s, C H ₃CO―) 2.05 (3H, s, C H ₃CO―), 3.51 (1H, m) 3.95 (1H, m) 4.48 (1H, d, 1Hz, 22-H), 4.93 (1H, m, 3-H) 5.07 (2H, m, 1-H) 5.54 (1H, m, 6-H) (2) (22R)-1α,3β,22-triacetoxycholest-5-en-25-ol (IV a1 ) and (22S)-1α,3β,22-triacetoxycholest-5-en-25-ol (IV a2 ) 109 mg of (22S)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a1 ) was dissolved in a mixture of methanol and tetrahydrofuran, and after adding thereto 3 drops of 2N-hydrochloric acid, the mixture was stirred for 3 hours at room temperature. The reaction solution was diluted with ethyl acetate, and washed with saturated aqueous sodium hydrogen carbonate and water, successively. After drying with magnesium sulfate, the solvent was distilled away. The residue obtained was dissolved in 10 ml of ethyl acetate, and after adding thereto 10 mg of 10% Pd-C, the mixture was stirred for 4 hours at room temperature under a hydrogen stream atmosphere. The catalyst was filtered off, and the mixture was washed with ethyl acetate, and a combined solution of filtrate and washing was concentrated under reduced pressure. The residue was dissolved in 0.5 ml of pyridine, and after adding thereto 0.1 ml of acetic anhydride, the mixture was stirred overnight at room temperature. After adding water to the reaction solution, the mixture was extracted with ethyl acetate. The extract organic layer was washed with 2N-hydrochloric acid, saturated aqueous sodium hydrogen carbonate, and water, successively, and dried over magnesium sulfate. The solvent was distilled away, and the residue was subjected to column chromatography (n-hexane-ethyl acetate = 4: 1) for purification to give 71.6 mg of (22R)-1α,3β,22-triacetoxycholest-5-en-25-ol (IV a1 ) (IV a1 ): Oily material ¹H-NMR (CDCl₃) δ ppm: 0.67 (3H, s, 18-H₃), 0.93 (3H, d, 7Hz, 21-H₃) 1.08 (3H, s, 19-H₃), 1.21 (s, 26-H₃), 1.22 (s, 27-H₃), 2.01 (3H, s, C H ₃CO), 2.02 (3H, s, C H ₃CO), 2.05 (3H, s, C H ₃CO), 4.95 (2H, m, 3-H, 22-H), 5.03 (1H, m, 1-H), 5.52 (1H, m, 6-H) By following the same procedure as above using as a starting material 154 mg of (22R)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a2 ), 107.9 mg of (22S)-1α,3β,22-triacetoxy-cholest-5-en-25-ol (IV a2 ) was obtained. (IV a2 ): Oily material ¹H-NMR (CDCl₃) δ ppm: 0.67 (3H, s, 18-H₃), 0.97 (3H, d, 7Hz, 21-H₃), 1.08 (3H, s, 19-H₃), 1.21 (s, 26-, 27-H₃), 2.01 (3H, s, C H ₃CO), 2.02 (3H, s, C H ₃CO), 2.05 (3H, s, C H ₃CO), 4.92 (2H, m, 3-H, 22-H), 5.06 (1H, m, 1-H), 5.51 (1H, m, 6-H) (3) (22R)-1α, 3β, 22-triacetoxycholest-5,7-dien-25-ol (V a1 ) and (22S)-1α, 3β, 22-triacetoxycholest-5,7-dien-25-ol (V a2 ) 18.4 mg of (22R)-1α,3β, 22-triacetoxycholest-5-en-25-ol (IV a1 ) was dissolved in 2 ml of carbon tetrachloride; the solution was refluxed under heating under argon gas atmosphere, and then 8.2 mg of N-bromo-succinimide was added to the mixture. After refluxing for 25 minutes, the mixture was cooled with ice-water, and the insoluble material was removed by filtration. The filtrate was concentrated under reduced pressure, and the residue was dissolved in 1.5 ml of xylene, and the solution was added dropwise to a refluxed solution of 1 ml of xylene and 1.5 ml of 2,4,6-collidine under argon gas stream atmosphere. After the addition was completed, the mixture was refluxed for 10 minutes. The mixture was diluted with ethyl acetate, and then was washed with 2N-hydrochloric acid, saturated aqueous sodium hydrogen carbonate, and water, successively, and dried over magnesium sulfate. The residue was dissolved in 10 ml of acetone, and after adding thereto 5 mg of p-toluenesulfonic acid, the mixture was stirred overnight under argon gas stream atmosphere in the dark at room temperature. The reaction solution was diluted with ethyl acetate, washed with water, and dried over magnesium sulfate. The solvent was removed by distillation, and the residue was subjected to preparative thin layer chromatography (solvent: n-hexane-ethyl acetate = 2: 1; developing: 5 times) for purification to give 1.75 mg of (22R)-1α,3β,22-triacetoxycholest-5,7-dien-25-ol (V a1 ). (V a1 ) UV (in ethanol) λ max ; 294, 282, 272 nm (4) (22R)-1α,22,25-trihydroxyvitamin D₃ (I a1 ) and (22S)-1α,22,25-trihydroxyvitamin D₃ (I a2 ) 1.75 mg of (22R)-1α,3β,22-triacetoxycholest-5,7-dien-25-ol (V a1 ) was dissolved in a mixture of 90 ml of benzene and 40 ml of ethanol, and mercury lamp irradiation was applied through Vycor filter under ice-cooling under argon gas stream, for 5 minutes. Then, the solution was refluxed under heating for 1 hour under argon gas stream atmosphere. The solvent was removed by distillation, and the residue was subjected to preparative thin layer column chromatography (solvent; n-hexane-ethyl acetate = 2: 1, 5 times developing) for purification to give triacetoxyvitamin D₃. This material was dissolved in 5 ml of tetrahydrofuran, and after adding thereto 2 ml of 5% potassium hydroxide-methanol, the mixture was stirred overnight at room temperature. The mixture was diluted with ethyl acetate, washed with water, and dried over magnesium sulfate. The solvent was distilled away, and the residue was subjected to preparative thin layer chromatography (solvent; ethyl acetate, 4 times developing for purification to give 112 µg of (22R)-1α,22,25-trihydroxyvitamin D₃ (Ia₁). (Ia₁) UV (in ethanol), λ max ; 265 nm, λ min ; 228 nm MS (m/n); 414 (M⁺-H₂O), 396, 269, 251, 152, 134 By following the same procedure as above using 2.08 mg of (22S)-1α,3β,22-triacetoxycholest-5,7-dien-25-ol (Va₂) obtained in (3) above, 134 µg of (22S)-1α, 22,25-trihydroxyvitamin D₃ (I a2 ) was obtained. (I a2 ) UV (ethanol); λ max 265 nm, λ min 228 nm MS (m/z); 414 (M⁺-H₂O), 396, 269, 251, 152, 134 High-performance liquid chromatography [(I a1 ): 12.5 minutes, (I a2 ): 10.8 minutes; Shimadzu LC-4A; Zorbax SiL 4.6 mm × 25 cm column; solvent-5% methanol in methylene chloride; 2 ml/min Example 2 (22R)-1α,25-dihydroxy-22-methoxyvitamin D₃ (I b1 ) and (22S)-1α,25-dihydroxy-22-methoxyvitamin D₃ (I b2 ) (1) (22S)-1α,3β-diacetoxy-22-methoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn (IV b1 ) and (22R)-1α,3β-diacetoxy-22-methoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn (IV b2 ) a) 100 mg of (22S)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a1 ) obtained in Example 1 (1) was dissolved in 1.5 ml of dimethylsulfoxide, and after adding thereto 13.2 mg of potassium hydroxide powder and 31µl of methyl iodide, the mixture was stirred for 3.5 hours at room temperature. The reaction solution was diluted with ethyl acetate, washed with water, dried over sodium sulfate, and concentrated. The residue was subjected to silica gel column chromatography (solvent; n-hexane: ethyl acetate = 7: 1) for purification to give 92 mg of (22S)-1α,3β-diacetoxy-22-methoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn (IV b1 ) (yield: 90 %). (IV b1 ): Oily material ¹H-NMR (CDCl₃)δ ppm: 0.69 (311, s. 18-H₃), 1.01 (3H, d, J = 6.5 Hz, 21-H a ) 1.09 (3H, s, 19-H₃), 1.52, 1.55 (6H, s, 26-H₃, 27-H₃) 2.03, 2.06 (6H, s, CH₃,COO―),3,37 (3H, s, OCH₃) 3.98 (1 H, m) 3.94 (1H, m) 3.97 (1H, d, J = 3,5 Hz, 22-H), 4.92 (1H, m, 3-H) 5.05 (2H, m, 1H) 5.52 (1H, m, 6-H) b) By following the same procedure as a) above using as a starting material 102.7 mg of (22R)-1α,3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a2 ) obtained in Example 1 (1), 70.1 mg of (22R)-1α,3ρ-diacetoxy-22-methoxy-25-tetrahydropyranyloxycholest-5-en-23-yn (IV b2 ) was obtained (yield: 67%) (IV b2 ) Oily material ¹H-NMR (CDCl₃)δppm: 0.68 (3H, s, 18-H₃), 1,08 (3H, d, J = 6,5Hz, 21-H₃) 1.08 (3H, s, 19-H₃), 1.5, (6H, s) 26-H₃, 27-H₃), 2.02, 2.05 (6H, s, CH₃COO―), 3.34 (3H, s, OCH₃) 3.49 (1H, m) 3.94 (1H, m) 3.98 (1H, s, 22-H), 4.92 (1H, m, 3-H) 5.05 (2H, m, 1-H) 5.55 (1H, m, 6-H) (2) (22R)-1α, 3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b1 ) and (22S)-1α, 3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b2 ) a) 105 mg of (22S)-1α,3β-diacetoxy-22-methoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn (IV b1 ) was dissolved in a mixture of 2 ml of tetrahydrofuran and 2 ml of methanol, and after adding thereto 1 drop of 2N hydrochloric acid, the mixture was stirred for 1.5 hours at room temperature. The reaction solution was diluted with ethyl acetate, washed with water, and dried over sodium sulfate. The solvent was removed for concentration of the reaction solution, the residue was dissolved in 10 ml of methanol, and after adding thereto 80 mg of 10% Pd-carbon (Pd-C), the mixture was stirred for 40 minutes at room temperature under a hydrogen gas stream atmosphere. The catalyst was removed by filtration and the filtrate was concentrated and subjected to column chromatography (solvent; n-hexane:acetic acid = 5: 1) for purification to give 57.7 mg of (22R)-1α,3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b1 ) was obtained (yield: 63%). (V b1 ): Oily material ¹H-NMR(CDCl₃) δppm: 0.71 (3H, s, 18-H₃), 0.87 (3H, d, J = 6Hz, 21-H₃) 1.09 (3H, s, 19-H₃), 1.21 (6H, s, 26-H₃, 27-H₃) 2.03, 2.06 (6H, s, CH₃COO―), 3.05 (1H, m, 22-H) 3.27 (3H, s, OCH₃), 4.92 (1H, m, 3-H) 5.02 (1H, m, 1-H), 5.55 (1H, m, 6-H) b) (22R)-1α,3β-diacetoxy-22-methoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn (IV b2 ) (78.9 mg) was treated in similar way to the above; 50.7 mg of (22S)-1α,3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b2 ) was obtained (yield: 73%) (V b2 ): Oily material ¹H-NMR (CDCl₃) δppm: 0.67 (3H, s, 18-H₃), 0.89 (3H, d, J = 6Hz, 21-H₃) 1.08 (3H, s, 19-H₃), 1.23 (6H, s, 26-H₃, 27-H₃) 2.03, 2.05 (6H,s, CH₃COO―), 3.10 (1H, m, 22-H) 3.36 (3H, s, OCH₃), 4.92 (1H, m, 3-H) (3) (22R)-1α, 3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b1 ) and (22S)-1α, 3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b2 ) a) 25.6 mg of (22R)-1α,3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b1 ) was dissolved in 2 ml of carbon tetrachloride, the mixture was refluxed under heating under an argon gas stream atmosphere, and 12 mg of N-bromosuccinimide was added to the mixture. After refluxing for 25 minutes, the mixture was cooled with ice-water, and the insoluble material was removed by filtration. The filtrate was concentrated under reduced pressure, and the residue was dissolved in 5 ml of tetrahydrofuran, and after adding a catalytic amount of tetra-n-butyl ammonium bromide, the mixture was stirred for 1 hour under an argon gas stream atmosphere. To the reaction mixture was added 0.17 ml of tetra-n-butyl ammonium fluoride (1M solution), and the mixture was stiired for 30 minutes at room temperature. The mixture was diluted with ethyl acetate, washed with 2N hydrochloric acid, saturated aqueous sodium hydrogen carbonate, and water, successively, and dried over sodium sulfate. The residue was dissolved in 10 ml of acetone, and after adding thereto about 5 mg of p-toluenesulfonic acid, the mixture was stirred overnight at room temperature under an argon gas stream atmosphere, in the dark. The reaction mixture was diluted with ethyl acetate, washed with water, and dried over magnesium sulfate. The solvent was distilled away, and the residue was purified using a column (Merck Company, Lichroprep RP-8, size A, solution; 15% water-methanol) to give 4.33 mg of (22R)-1α,3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b1 ). VI b1 : UV (methanol); λ max 294,282,272n. b) (22S)-1α,3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en By following the same procedure as above using (22S)-1α,3β-diacetoxy-25-hydroxy-22-methoxy-cholest-5-en (V b2 ), 5.40 mg of (22S)-1α,3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b2 ) was obtained. VI b2 ; UV (in methanol); λ max 294,282,272 nm (4) (22R)-1α,25-dihydroxy-22-methoxyvitamin D₃ (I b1 ) and (22S)-1α,25-dihydroxy-22-methoxyvitamin D₃ (I b2 ) a) 4.33 mg of (22R)-1α,3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b1 ) was dissolved in a mixture of 90 ml of benzene and 40 ml of ethanol, and the solution was irradiated with a medium pressure mercury lamp through a Vycor filter under ice-cooling for 5 minutes. The solution was refluxed under heating for 1 hour under an argon atmosphere. The solvent was distilled away, and the residue was purified by preparative thin layer chromatography (solvent; n-hexane; ehtyl acetate = 2: 1, 5 times developping) to give 1,25-diacetoxy-22-methoxy-vitamin D₃. The thus obtained material was dissolved in 5 ml of tetrahydrofuran, and after adding thereto 2 ml of 5%KOH-methanol solution, the mixture was stirred under an argon atmosphere in the dark at room temperature. The mixture was diluted with ethyl acetate, washed with water, and dried over sodium sulfate. The solvent was distilled away, and the residue was purified by high performance liquid chromatography (Zorbax SIL, 4.6 mm × 25 cm, solvent; 20% 2-propanol in hexane; 2 ml/min., retention time; 7.6 minutes) to give 1.02 mg of (22R)-1α,25-dihydroxy-22-methoxyvitamin D₃ (I b1 ). I b1 ; UV (in ethanol); λmax 265 nm, λmin 228 nm MS (m/z); 446(M⁺), 428(M⁺-H₂O), 383, 366. 290, 271, 251, 152, 134 ¹H-NMR (CDCl₃) δppm: 0.59 (3H, s, 18-H₃), 0.89 (3H, d, J = 6, 6Hz, 21-H₃) 1.22 (6H, s, 26-H₃, 27-H₃), 3.07 (1H, m, 22-H) 3.29 (3H, s, OCH₃), 4.21 (1H, m, 3-H) b) By using as a starting material 5.40 mg of (22S)-1α,3β-diacetoxy-22-methoxy-cholest-5,7-dien-25-ol (VI b2 ), in the same way as described above, and after purification by high performance chromatography (retention time: 7.8 minutes), 0.743 mg of (22S)-1α, 25-dihydroxy-22-methoxyvitamin D₃ (I b2 ) was obtained. I b2 ; UV (ethanol); λ max 265 nm, λ min 228 nm MS (m/z); 446 (M⁺), 428 (M⁺-H₂O), 383, 366, 290, 271, 251, 152, 134 ¹H-NMR (CDCl₃) δppm: 0.55 (3H, s, 18-H₃), 0.91 (3H, d, J = 6.6Hz, 21-H₃) 1.24, 1.25 (1H, s, 26-H₃, 27-H₃) 3.11 (1H, m, 22-H), 3.38 (3H, s, OCH₃) 4.21 (1H, m, 3-H), 4.45 (1H, m, 1-H) 5.01 (1H, s, 19-H), 5.34 (1H, m, 19-H) 6.03 (1H, d, J = 11Hz, 7-H), 6.39 (1H, d, J = 11Hz, 6-H) Reference Example (22S,23Z)-1α,3β-diacetoxycholest-5,22-dien-22,25-diol 22-p-bromobenzoate (VIII a1 ) and (22R,23Z)-1α 3β-diacetoxycholest-5,22-dien-22,25-ol 22-p-bromobenzoate (VIII a2 ) 30 mg of (22S)-1α, 3β-diacetoxy-25-tetrahydropyranyloxy-cholest-5-en-23-yn-22-ol (III a1 ) obtained in Example 1 (1) was dissolved in 5 ml of methanol, and after adding thereto 15 mg of 5% Pd-CaCO₃ and 20 µl of quinoline, the mixture was stirred for 6 hours in a hydrogen gas stream atmosphere. The catalyst was removed by filtration, and after washing with ethyl acetate, a combined solution of the filtrate and the washing was concentrated under reduced pressure. The residue was dissolved in 2 ml of pyridine, and after adding thereto 55 mg of p-bromobenzoychloride, the mixture was stirred overnight at room temperature. After adding water,the mixture was extracted with ethyl acetate. The extract organic layer was washed with 2N-hydrochloric acid and saturated aqueous sodium hydrogen carbonate, and dried over magnesium sulfate. The solvent was distilled away, and the residue was dissolved in 6 ml of a mixture of 3 ml of methanol and 3 ml of tetrahydrofuran, After adding 1 drop of 2N-hydrochloric acid, the mixture was stirred for 1 hour at room temperature. The reaction solution was diluted with ethyl acetate, washed with water, and dried over magnesium sulfate. The solvent was distilled away, and the residue was purified by preparative thin layer chromatography (solvent; n-hexane; ethyl acetate = 10: 1, 6 times developing) to give 12.4 m, of (22S, 23Z)-1α 3β -diacetoxycholest-5,22-dien-22, 25-diol 22-p-bromobenzoate (VIII a1 ). Melting point: 132-134°C (recrystallized from methanol) ¹H: NMR (CD₃OD) δ ppm: 0.67 (3H, s, 18-H₃), 1.04 (3H, s, 19-H₃), 1.09 (3H, d, 6Hz, 21-H₃), 1.23 (s, 26, 27-H₃), 1.92 (3H, s, CH₃CO―), 1.97 (3H, s, CH₃CO), 5.02 (1H, m, 1-H), 5.36 (1H, dd, 10.5 12.5 Hz, 23-H), 5.48 (1H, m, 6-H), 5.65 (1H, d, 12 Hz, 24-H) 6.34 (1H, dd, 3.3, 10.5 Hz, 22-H), 7.59 (2H, d, 7Hz), 7.86 (2H, d, 7Hz) The compound (VIII a1 ) shows J 22,23 = 10.5 Hz in ¹H-NMR, and its proton is in the trans-configuration. Its CD spectrum shows Δ ε = 7.27, and so the compound is in the (22S)-configuration. By following the same procedure as above using 30.1 mg of (22R)-1α, 3β-diacetoxy-5-tetrahydropyranyloxycholest-5-en-23-yn-22-ol (III a2 ), 4.0 mg of (22R, 23Z)-1α,3β-diacetoxycholest-5,22-dien-22,25-diol 22-p-bromobenzoate (VIII a2 ) was obtained. Melting point: 179-181°C (recrystallized from acetone -n-hexane) ¹H-NMR(CD₃CO) δppm; 0.68(3H, s, 18-H₃), 1.04 (3H, s, 19-H₃),1.12 (3H, d, 6Hz, 21-H₃), 1.27 (s, 26-H₃), 1.38 (s, 27-H₃), 1.92 (3H, s, C H ₃CO-), 1.94 (3H, s, C H ₃CO―). 4.96 (1H, m, 1-H), 5.35 (1H, dd, 8.6Hz 12Hz, 23-H), 5.45 (1H, m, 6-H), 5.50 (1H, d, 12Hz, 24-H), 6.41 (1H, dd, 1.0Hz8.6Hz, 22-H), 7.60 (2H, d, 7Hz, Benzene ring) 7.85 (2H, d, 7Hz, benzene ring) The compound (VIII a2 ) shows J 22,23 = 8.6Hz in ¹H-NMR, and its CD spectrum (methanol) shows Δε = -5.85, and so the compound is in the (22R)-configuration. Additional Example to Example 1 (3): ― By following the procedure of Example 1 (3), using as starting material 14 mg of (22S)-1α,3β,22-triacetoxycholest-5-en-25-ol (IV a2 ), 2.08 mg of (22S)-1α,3β,22-triacetoxycholest-5,7-dien-25-ol (V a2 ) was obtained. (V a2 ) UV (in ethanol), λ max : 294, 282, 272 nm

Claims: 1. A compound of formula wherein R represents a hydrogen atom or C n to C₅ alkyl group. 2. A compound according to claim n wherein R is methyl. 3. A compound according to claim n or 2 wherein the 22-position has the S-configuration. 4. Compound according to claim 1 which is selected from [22R]-1α,22,25-trihydroxyvitamin D₃, [22S]-1α,22,25-trihydroxyvitamin D₃ and a mixture of the two optical isomers. 5. Compound according to claim 1 which is selected from [22R]-1α,25-dihydroxy-22-methoxyvitamin D₃, [22S]-1α,25-dihydroxy-22-methoxyvitamin D₃ and a mixture of the two optical isomers. 6. A derivative of a compound according to any of claims 1 to 5 which derivative is convertible in vivo to a compound according to any one of claims 1 to 5. 7. A metabolite of a compound according to any of claims 1 to 5 which metabolite has the effect of inducing the differentiation of tumor cells. 8. A pharmaceutical composition containing as active ingredient a compound according to any of claims 1 to 6. 9. A compound according to any of claims 1 to 7 for use in a method of inducing the differentiation of tumor cells. 10. The use of a compound according to any of claims 1 to 7 for the preparation of a pharmaceutical composition for inducing the differentiation of tumor cells.

Inventors: EGUCHI, TADASHI, IKEGAWA, NOBUO
Applicants: YAMANOUCHI PHARMACEUTICAL CO. LTD.
Application year: 1988
Main classification: C07C401
IPC codes: C07J17, C07J9, C07C401