The invention relates to a process for the synthesis of high purity d-( 17α)-13-ethyI-17hydroxy-18,19-dinorpregn-4-ene-20-yne-3-one-oxime (further on norelgestromine) via acetylation of d-norgeslrel at position 17, oximation of the oxo group atposition 3 of the obtained 17-acetoxy derivative, and finally hydrolyzing the acetoxy group at position 17 of the obtained 3-oximederivative. The process according to our invention is as follows: the starting material, d-(17α-17-hydroxy-13-ethyl-18,19-dinor-pregn-4-ene-20-yne-3one (d-norgestrel) - purity 93-94 % - is acerylated with acetic anhydride in acetic acid, in the presence ofzinc chloride and hydrogen chloride, or 70 % perchloric acid in an inert gas atmosphere, and after completion of the reaction theexcess of acetic anhydride and the "enol acetate" by-product are decomposed with aqueous hydrochloric acid then the formedd-(17α)-17-acetoxy-13-ethy]-18,19-dinoipregn-4-ene-20-yne-3-one is isolated from the reaction mixture by addition of ice-water,the precipitated product is filtered off, washed with water, dried, dissolved in dichloromethane or acetone and clarified with silica gelor aluminum oxideand charcoal, after filtration of the clarifier the resulted solution is concentrated and the residue is recrystallized,the obtained d-(17α)-17-acetoxy-13-eyhyal-18,l9-dinorpregn-4-ene-20-yne-3-one is reacted either with hydroxylammonium acetateor with hydroxylammonium chloride in the presence of sodium acetate, in acetic acid in nitrogen atmosphere under vigorous stirringfor about 1 hour, aftercompletion of the reaction water is added, the precipitated product is filtered off, washed with water, dried andrecrystallized, the obtained d-(17α-17'acetoxy-13-ethyl-18,19-dinorpregn-4-ene-20-yne-3-one-oximeis hydrolyzed with an equiv-alent amount of an alkali metal hydroxide in a C1 -C4 alkanol solution, in nitrogen atmosphere between a temperature of about 5-38°C, under vigorous stirring, after completion of the reaction the mixture is diluted with water and the pH of the resulted suspensionis adjusted to 7,5-9 with acetic acid, the precipitated product is filtered off, washed with water, dried, the crude product is dissolvedin ethanol, clarified with charcoal, and after filtration of the clarifier water is added to the obtained solution, the precipitated high pu-rity d-(17α)-17-acetoxy-13-ethyl-18,19-dinorpregn-4-ene-20-yne-3-one-oxime is filtered off, washed with water and in given caserecrystallized from ethanol.
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