Sodium Azide → 2-Azido-2-(4-nitrophenyl)ethan-1-ol

To 60 ml of MOPS buffer (50 mM, pH=7.0), 0.47 gram (3.2 mmol) of racemic para-nitro styrene oxide was added and the suspension was stirred for 60 min. The halohydrin dehalogenase, obtained as described in Example 1, (29 mg in 6 ml buffer) was added. A prepared stock solution of 0.12 gram (1.6 mmol) NaN3 in 5 ml MOPS buffer was slowly added over a period of 24 hours. The reaction was stopped and the suspension was three times extracted with diethylether. After separating, the organic phase was dried with MgSO4, and removed by rotary evaporator yielding an orange oil. This mixture was redissolved in diethylether and the composition and e.e. of the products were determined by chiral HPLC. The mixture mainly consisted of (S)-para-nitro styrene oxide in 46% yield (98% e.e.) and (R)-2-azido-1-(para-nitrophenyl)ethanol in 47% yield (97% e.e.). The chemical side product 2-azido-2-(para-nitrophenyl)ethanol was formed to a total of 4% of the reaction mixture. The product of chemical hydrolysis of the epoxide, para-nitrophenyl ethanediol was formed in 3%. All the mentioned yields are calculated yields. Flash chromatography on silica 60H using heptane/ethylacetate (ratio 7:3) as eluent yielded pure epoxide and azido alcohols. The NMR data were identical with synthesized racemic reference compounds.