4-Amino-1-(2-deoxy-2,2-difluoro-a-D-erythro-pentofuranosyl)-2(1H)-pyrimidinone Hydrochloride synthesis

Yield:-

Reaction Conditions:

with hydrogenchloride in water;isopropyl alcohol at -4 - 60; for 6.5 h;

Steps:

6
EXAMPLE 6: PREPARATION OF GEMCITABINE HYDROCHLORIDE OF FORMULA I75 ml of isopropyl alcohol and 25 g of gemcitabine base obtained from Example 5 were charged into a round bottom flask and then the isopropyl alcohol solvent was distilled off under a vacuum of 600 mm Hg at 47°C. The above step was repeated two more times. Again 75 ml of isopropyl alcohol was charged to above obtained residue and heated to 60⁰C. 10 ml of 36% aqueous hydrochloric acid was added to the above reaction solution and then allowed to cool to 27°C. Again cooled the reaction suspension to -4°C and stirred for 6.5 hours at -4°C. The obtained solid suspension was filtered and the wet solid washed with 75 ml of acetone. The solid was dried at 39°C under vacuum for 3 hours to afford 9.4 g of title compound. Purity by HPLC: 98.5 % (α: 11.19 %, β: 87.31 %).

References:

DR. REDDY'S LABORATORIES LTD.;DR. REDDY'S LABORATORIES, INC. WO2007/117760, 2007, A2 Location in patent:Page/Page column 21