(2R)-3-Chloro-1,2-propanediol → (2R)-3-{4-[5-(5-ethyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-2,6-dimethyl-phenoxy}-propane-1,2-diol

Participants

Reaction Steps

To a solution of 4-[5-(5-ethyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-2,6-dimethyl-phenol (79 mg, 0.263 mmol) in isopropanol (3 mL) and 3 N aq. NaOH (0.6 mL), (R)-3-chloro-propane-1,2-diol (148 mg, 1.31 mmol) is added. The mixture is stirred at rt for 2 h, then at 65° C. for 16 h before another portion of (R)-3-chloro-propane-1,2-diol (119 mg, 1.05 mmol) is added. Stirring is continued at 65° C. for 24 h. The reaction mixture is diluted with water and extracted with diethyl ether. The org. extract is dried over MgSO4, filtered and evaporated. The crude product is purified by chromatography on prep. TLC plates with DCM containing 4% of 7 N NH3 in methanol to give (2R)-3-{4-[5-(5-ethyl-thiophen-2-yl)-[1,2,4]oxadiazol-3-yl]-2,6-dimethyl-phenoxy}-propane-1,2-diol as an off-white solid; LC-MS: tR=0.99 min; [M+1]+=375.13; 1H NMR (CDCl3): δ 7.83 (s, 2H), 7.80 (d, J=3.8 Hz, 1H), 6.93 (d, J=3.8 Hz, 1H), 4.20-4.11 (m, 1H), 3.97-3.93 (m, 1H), 3.91 (dd, J=11.5, 4.3 Hz, 1H), 3.85 (dd, J=11.5, 5.5 Hz, 1H), 2.97 (q, J=7.5 Hz, 2H), 2.39 (s, 6H), 1.41 (t, J=7.5 Hz, 3H).

Provenance & Evidence