Hydrogen Bromide → 2-Amino-4-chloro-7-[3,5-bis-O-(2,4-dichlorophenylmethyl)-2-C-methyl-beta-D-ribofuranosyl)-7H-pyrrolo[2,3-d]pyrimidine

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Reaction Steps

To an ice-cold solution of product from Step C of Example 62 (1.27 g, 2.57 mmol) in CH2Cl2 (30 mL) was added HBr (5.7 M in acetic acid; 3 mL) dropwise. The reaction mixture was stirred at room temperature for 2 h, concentrated in vacuo and co-evaporated with toluene (2×15 mL). The resulting oil was dissolved in MeCN (15 mL) and added dropwise into a well-stirred mixture of 2-amino-4-chloro-7H-pyrrolo[2,3-d]pyrimidine [for preparation see Heterocycles 35: 825 (1993)] (433 mg, 2.57 mmol), KOH (85%, powdered) (0.51 g, 7.7 mmol), tris-[2-(2-methoxyethoxy)ethyl]amine (165 μL, 0.51 mmol) in acetonitrile (30 mL). The resulting mixture was stirred at rt for 1 h, filtered and evaporated. The residue was purified on a silica gel column using hexanes/EtOAc, 5/1, 3/1 and 2/1 as eluent to give the title compound as a colorless foam (0.65 g).

Provenance & Evidence