production method | vitamin D2 (I) is used as raw material. Vitamin D2(12.5g,31.5 mmol) was dissolved in 50ml of liquid sulfur dioxide, and the mixture was stirred and refluxed for 30min. It was then dissolved in 4.5 of dimethylformamide and imidazole (5.0g,66 mmol) and tert-butyldimethylsilyl chloride (g,33 mmol) were added and stirred at 20 °c for 90min. The reaction was partitioned between 500ml of ethyl acetate and 200ml of water. The organic layer was separated, washed with water and brine, dried and concentrated. The residue was separated by chromatography (eluted with 30% diethyl ether in petroleum ether solution), and 9.4g of compound (Ⅱ a) was obtained in 52% yield, melting point 117~118 ℃ (decomposition); and 7.7g of compound (II B), yield 42%, melting point 121~122 C (decomposition). Compound (IIA) or (IIB) or a mixture thereof (16.4g,28.5 mmol) was suspended in 96% ml of ethanol, and 20g of sodium bicarbonate was added and refluxed for 90min. It was cooled, partially concentrated under reduced pressure, and the remaining solution was partitioned between ethyl acetate and water. The organic layer was separated, washed with water and brine, dried and concentrated. The residue was dissolved in a solution of N-methylmorpholine N-oxide monohydrate (16g,119 mmol) in of dichloromethane. Filtration, a solution of selenium dioxide (3.0g,27 mmol) in of methanol was added rapidly to the filtrate under reflux. Refluxing for 50min. After cooling, dilution with dichloromethane, washing with water and brine, drying and concentration. The residue was dissolved in 80ml of dimethylformamide, imidazole (4.3g,63 mmo1) and tert-butyldimethylsilyl chloride (5.1g,34 mmo1) were added and stirred at 20 °c for 90min,, the reaction was partitioned between 450ml of ethyl acetate and 200ml of water. The ethyl acetate layer was separated and washed with water and brine, Drying and concentration gave a crystalline solid. The solid was isolated over silica gel (1% ether in petroleum ether) and then recrystallized from ether-ethanol to give 113g of compound (III), m. P. 114-°c. Compound (III)(4.0g,6.2mmol) was dissolved in 10ml of diethyl ether and 50ml of liquid sulfur dioxide and stirred for 30min. Sulfur dioxide and ether were distilled off, the residue was dried under reduced pressure, and then separated by chromatography (20% ether in petroleum ether solution) to obtain compound (Ⅳ a), melting point 107~109 ℃ (decomposition); and compounds (IV B). Compound (IV a) (4.4g,6.2 mmol) was dissolved in mL of dichloromethane and 40ml of methanol, and O3 was added at -65 °c to complete the reaction of the starting material, which took about 40min. Nitrogen was bubbled through and triphenylphosphine (2.5g,9.5 mmol) was added. The temperature was slowly raised to 0 °c, diluted with dichloromethane, washed with 5% sodium bicarbonate solution, water and brine successively, dried and concentrated. Residue chromatography (30% ether in petroleum ether solution elution), 81% G of compound (Va), yield 122, melting point 124 ~ C (decomposition); And compound (Vb). Compound (V)(14.3g,22 mmol) was suspended in ml ethanol, 14g of sodium bicarbonate was added and refluxed for 90min. It was cooled and partially concentrated under reduced pressure. The remaining solution was partitioned between 350ml of ethyl acetate and 200ml of water. The organic layer was separated, washed with water and brine, dried and concentrated. 12.6g of a crystalline product containing 90% of the compound (VI a) and 5% of the compound (IV B) were obtained and used directly in the next step. The mixture (10.5g) of the above compounds (VI a) and (vi B) and the halide (X)(15g,44 mmol) were dissolved in 60ml of dimethyl sulfoxide and reacted at 105 ° C. For 4 hours. Cool and partition between 250ml ethyl acetate and 200ml water. The ethyl acetate layer was separated, washed with water and brine, dried, and concentrated under reduced pressure. The residue was purified by chromatography (10% ether in petroleum ether) and recrystallized from ether-methanol to give 7.51g of compound (VII), yield 63% [in terms of compound (V)], melting point 123 to 124 °c. Compound (VII)(4.31g,6.74 mmol) was dissolved in 8ml of tetrahydrofuran, and 18ml of 0.4mol/L CeCl3 was added under cooling and stirring in an ice bath? 6H2O methanol solution, and then add 9ml methanol. 0.50g of sodium borohydride was added in portions over 5min. After addition, the mixture was stirred for 10min. Partition was performed between 250ml of ethyl acetate and 200ml of water. The organic layer was separated, washed with 100ml of water, dried, and concentrated under reduced pressure. The residue was separated by chromatography to give 1.42g of compound (VIII) in 33% yield with a melting point of 122-123 °c. Compound (VIII)(1.13g,1.76 mmol), MG of anthracene and 1 drop of triethylamine were dissolved in 75ml of toluene and irradiated with a high-pressure UV lamp at 20 °c for 60min. It was filtered and concentrated under reduced pressure. The residue was purified by chromatography (15% ethyl acetate in petroleum ether) to give 92% G of compound (IX) in yield. Compound (ix)(1.03g,1.61 mmol) and tetrabutylammonium fluoride (2.1g,6.7 mmol) were dissolved in 40ml of tetrahydrofuran and reacted at 60 ° C. For 50min. Cool and partition between 150ml of ethyl acetate and 100ml of 2% sodium bicarbonate solution. The organic layer was separated, washed with water and brine, dried and concentrated. The residue was purified by silica gel column chromatography (eluted with ethyl acetate) to give 73% mg of calcipotriol in 166 yield, melting point 168-°c. |