Example 3: Preparation of 1-[3,5-di-O-(p-chlorobenzoyl)]-2-deoxy-α-D-ribofuranosyl chloride
To a 250 mL four-necked round-bottomed flask under nitrogen protection was added 1-O-methyl-3,5-di-O-(p-chlorobenzoyl)-2-deoxy-α/β-D-ribofuranose (15.94 g), glacial acetic acid (60 mL), anhydrous chloroform (30 mL), anhydrous dioxane (30 mL) and acetyl chloride (0.87 g). Under stirring conditions, gaseous HCl (11.5 g) was slowly passed while the reaction temperature was controlled between 13 and 15 °C. During this process, 1-[3,5-di-O-(p-chlorobenzoyl)]-2-deoxy-α-D-ribofuranosyl chloride was gradually crystallized and precipitated.After the completion of HCl passage, the reaction mixture was continued to be stirred at 12 °C for 20 min. Subsequently, the product was collected by filtration and washed with anhydrous hexane (20 mL). After drying, 12.4 g of the target compound 1-[3,5-di-O-(p-chlorobenzoyl)]-2-deoxy-α-D-ribofuranosyl chloride was obtained as a white powder in 77% yield.
