Ammonium Chloride → (3R*,4R*)-4-azido-3-hydroxy-piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

Heat a mixture of racemic trans-7-oxa-3-aza-bicyclo[4.1.0]heptane-3-carboxylic acid tert-butyl ester (0.56 mol, 112 g), sodium azide (1.12 mol, 73.08 g), ammonium chloride (0.56 mol, 30.07 g) and methanol/water (3:1) (1 L) at 65° C. for 16 h. Dilute the reaction mixture with water, extract with dichloromethane, and wash the organic layer with saturated sodium bicarbonate and brine solution. Dry the organic layer over anhydrous sodium sulfate, filter, and concentrate. Purify the residue on a silica gel column using 6% ethyl acetate in hexanes as eluent to obtain the title compound (42.3 g, 42%) as a light yellow oil. 1H NMR (400 MHz, CDCl3) δ 1.48 (s, 9H), 1.84 (br s 1H), 1.97-2.01 (m, 1H), 2.74-2.82 (m, 1H), 2.88 (br s, 1H), 3.37-3.40 (m, 1H), 3.50 (br s, 1H), 3.91 (br s, 1H), 4.09 (dd, 1H). ES-MS m/z 143 [M−Boc]+.

Provenance & Evidence