11-beta, 17-dihydroxypregna-1,4–diene-3,20-disemicarbazone-21-yl acetate synthesis

Yield:96580-08-4 31.9 g

Reaction Conditions:

with potassium acetate;acetic acid in acetone; for 4.5 h;Reflux;Reagent/catalyst;

Steps:

2 Implementation of the example two

Sequentially to the reaction flask by adding 750 ml acetone, 30g also original intermediate prednisolone acetate, 15g potassium acetate, 51 ml of acetic anhydride, 9 ml acetic acid, reflux reaction temperature rise 4.5 hours. TLC shows the reaction is complete, normal pressure distillation recovery most of the solvent, the solvent evaporation to dryness under reduced pressure, lowering the temperature to 5 °C the following, stirring 30 minutes later, static 2 or more hours, filtering, drying to obtain 31.9g ester.The 30g the esterified 150 ml mass percent concentration of 36% hydrochloric acid, 240 ml water, 15 ml chloroform solution of, for 25 °C -30 ° C stirring 30 minutes-soluble cleaning. Cooling, in 18 °C -22 ° C instillment by 30g sodium nitrite and 1050 ml water solution. Is omitted, to continue for 18 °C -22 ° C reaction 3 hours. TLC shows the reaction is complete, cooling to 0 °C, for 0 °C -5 ° C stirring 0.5 hours, for 2 hours, filtered, washed to neutral, is added to the resulting filter cake 30 ml ethanol heating reflux 30 minutes, cooling, in -5 ° C -0 ° C stirring 0.5 hours, for 2 or more hours, filtering, drying to obtain 21.8g crude prednisolone acetate. ACOH predinisone long Cupin Decolouring refining in ethanol to obtain 19.5g prednisolone acetate, HPLC purity 99.0%.

References:

CN105503986,2016,A Location in patent:Paragraph 0027; 0028