Bromide ion → HCID 88669256, compound

Participants

Reaction Steps

To a stirred suspension of Ia (R2 =R3 =H) (280 mg, 0.68 m mole) and Na2CO3 (36 mg, 0.34 m mole) in dry DMF (5 ml) was added at -10° C. over 10 min. a solution of acetoxymethyl bromide in dry DMF (104 mg, 0.68 m mole/100 μl). After 30 min, additional Na2CO3 (18 mg, 0.17 m mole) and the bromide solution (52 mg, 0.34 m mole/50 μl) were added in small portions over 10 min. The mixture was stirred at the same temperature for 30 min. The reaction mixture showing four spots at Rf 0.10 (BMY-28232), 0.15, 0.60 and 0.75 by TLC (Merck Kieselgel 60 F254, 10:1 MeCN--H2O) was diluted with AcOEt (25 ml), washed with water (×3) and a saturated NaCl solution, dried over MgSO4 and evaporated. The residue was dissolved in a small amount of CHCl3 and charged on a column of Kieselgel 60 (18 g), which was washed with CHCl3 (50 ml) and eluted with MeOH--CHCl3 (1:20, 250 ml). The fractions showing a spot at Rf 0.60 by TLC were combined and evaporated in vacuo. The residue was dissolved in benzene and lyophilized to afford 45 mg (14%) of the title compound. M.p. 107-110° C. Estimated purity 70%. HPLC (Lichrosorb 4×300 mm, 2:3 MeCN--H2O): retention time, 6.0 min.

Provenance & Evidence