Methanesulfonyl chloride → N-Benzyloxycarbonyl-4-methanesulphonyloxy-L-cis-proline methyl ester

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Reaction Steps

1.59 g (5.7 mmol) of N-benzyloxycarbonyl-4-hydroxy-L-cis-proline methyl ester are dissolved in 50 ml of abs. pyridine and cooled to 0° C. 0.6 ml (7.7 mmol) of methanesulphonyl chloride is added dropwise at 0° C., and the mixture is subsequently stirred at room temperature for 3 hours. The mixture is then concentrated and 100 ml of methylene chloride are added to the residue, and this latter mixture is then extracted 2 x by shaking with a 10% solution of NaHCO3, dried over sodium sulphate and concentrated once again, with the residue being subsequently distilled repeatedly with toluene. Yield: quantitative Rf : 0.33, eluent, toluene/EtOH (10:1)

Provenance & Evidence