METHOD OF OBTAINING AND PURIFICATION OF GEMCITABINE HYDROCHLORIDE Russian patent published in 2009 - IPC A61K31/7068 C07H19/06 

FIELD: medicine.

SUBSTANCE: invention relates to method of obtaining gemcitabine hydrochloride, characterised by the following: 2,2-dimethyl-[1,3]-dioxolane-4-carbaldehyde is subjected to interaction with ethyl bromodifluoracetate in presence of zinc in organic solvent medium processing reaction mixture with ultrasound for 5-60 minutes, obtained ethyl 3-hydroxy-2,2-difluoro-3-[2,2-dimethyl-[1,3]dioxolane-4-yl]propionate is subjected to hydrolysis and cyclisation by means of ion-exchange resin in water-alcohol medium obtaining (4R,5R)-4-hydroxy-5-hydroxymethyl-3,3-difluorodihydrofuran-2(3H)-on, which is processed with solution of trimethylchlorosilane in dichloromethane obtaining (4R,5R)-4-trimethylsilyloxy-5-((trimethylsilyloxy)methyl)-3,3-difluorodihydrofuran-2(3H)-on, which is subjected to reduction by means of lithium diisopropylalumohydride in organic solvent medium at cooling to -70°C obtaining (4R,5R)-2-hydroxy-4-(trimethylsilyloxy)-5-((thrimethylsilyloxy)methyl)-3,3-difluorotetrahydrofurane, which is converted into (4R,5R)-2-methylsulphonyloxy-4-(trimethylsilyloxy)-5-((trimethylsilyloxy)methyl)-3,3-difluorotetrahydrofurane by processing with methane sulphonylchloride in solvent medium at cold, obtained (4R,5R)-2-methylsulphonyloxy-4-(trimethylsilyloxy)-5-((trimethylsilyloxy)methyl)-3,3- difluorotetrahydrofurane after optic isomer separation is processed with bis-trimethylsilylacetylcytozine in water-free dichlorethane and boil with trifluoromethane sulphonyloxymethylsilane with further cooling and separation of obtained gemcitabine in form of base or hydrochloride, as well as method of gemcitabine hydrochloride purification by its re-crystallisation from water solution with processing with ultrasound.

EFFECT: invention results in increase of ratio 3-(R)-hydroxy-isomer to 3(S)-hydroxy-isomer.

6 cl, 2 dwg, 4 ex