反应详情

Sodium N-carbobenzoxy4-amino-2-oxobutyric acid 5 (67 mg, 0.25 mmol) and sodium formate (17 mg, 0.25 mmol) in aqueous Tris buffer (20 cm3) were deoxygenated by bubbling a stream of nitrogen through the solution for 30 minutes. RLB2HADH in Tris buffer (0.5 cm3, 2 mg dry mass of enzyme), β-nicotinamide adenine dinucleotide (2 mg), formate dehydrogenase (2 mg) and dithiothreitol (1M, 1 μl) were added and the mixture was stirred at room temperature under nitrogen, the reaction was complete in 1 day. The pH was maintained at from 6.5-7.0 by the addition of dilute aqeuous hydrochloric acid (0.1 M). When no further change in pH was observed, the mixture was concentrated in vacuo. Saturated brine (5 cm3) and concentrated hydrochloric acid (0.5 cm3) were added and the mixture was extracted with ethyl acetate (3×20 cm3). The combined organic phases were dried over anhydrous sodium sulphate and concentrated in vacuo to give (R)-N-carbobenzoxy-4-amino-2-hydroxybutyric acid 6 as an off-white solid (55 mg, 89% yield).

1. customby bubbling a stream of nitrogen through the solution for 30 minutes
2. additionRLB2HADH in Tris buffer (0.5 cm3, 2 mg dry mass of enzyme), β-nicotinamide adenine dinucleotide (2 mg), formate dehydrogenase (2 mg) and dithiothreitol (1M, 1 μl) were added
3. temperatureThe pH was maintained at from 6.5-7.0 by the addition of dilute aqeuous hydrochloric acid (0.1 M)
4. concentrationthe mixture was concentrated in vacuo
5. additionSaturated brine (5 cm3) and concentrated hydrochloric acid (0.5 cm3) were added
6. extractionthe mixture was extracted with ethyl acetate (3×20 cm3)
7. dry with materialThe combined organic phases were dried over anhydrous sodium sulphate
8. concentrationconcentrated in vacuo