Thionyl Chloride → (R)-4-methyl-3-(2-pyridyl)-[1,2,3]oxathiazolidine 2-oxide

A solution of (R)-N-(2-pyridyl)-2-aminopropanol (20.0 g, 0.13 moles) and N,N-diisopropylethylamine (33.6 g, 0.13 moles) in dichloromethane (500 ml) was cooled to 5° C. Then thionyl chloride (15.5 g, 0.13 moles) in dichloromethane (100 ml) was added slowly whilst the temperature was kept below 10° C. The mixture was stirred for 0.5 h. and ice cold water (500 ml) was added. The organic phase was separated and washed with water (5×500 ml). The aqueous phase was back-extracted with dichloromethane (2×500 ml), the organic phases were combined, dried (MgSO4) and evaporated in vacuo to give a brown oil. This was purified on a silica column, eluting with diethyl ether to give (R)-4-methyl-3-(2-pyridyl)-[1,2,3] oxathiazolidine 2-oxide (154.4 g) as a clear oil.