反应详情

Sodium borohydrate (2.4 g, 64 mmol) was added in portions to a stirred ice cold solution of 1,4 cyclohexanedione monoethylene ketal 38 (20 g, 128 mmol) in 60 mL of methanol (Step 35). After addition was complete, 1N HCl was added to the solution dropwise until a pH of 8 was obtained and then the solvent was removed by roto-evaporation. The product 39 (16.8 g, 84%) showed a single spot on TLC (Rf=0.4, ethyl acetate/hexane 20:80 solvent system, visualization was with acidic vanillin ethanol solution) and was used without further purification. 1H NMR (CDCl3) δ1.6-1.9 (m, 8H, ring-CH2), 3.8 (m, 1H, CH--O), 4.0 (s, 4H, ketal-CH2), 5.3 (s, 1H, OH).

1. additionAfter addition
2. customwas obtained
3. customthe solvent was removed by roto-evaporation
4. customwas used without further purification