tert-butyl N-(2-chloro-4-hydroxyphenyl)carbamate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a 50 mL round bottomed flask with a stirring bar and an argon inlet was added 4-(1,1-dimethylethoxycarbonyl)amino-3-chlorophenol (0.831 g, 3.41 mmol) and DMF (16 mL). This mixture was cooled in an ice bath then Cs2CO3 (0.552 g, 1.69 mmol) and ethyl bromoacetate (0.37 mL, 3.34 mmol) were added. The resulting mixture was stirred for 6 h, during which time the cooling bath was allowed to expire. The mixture was filtered through a frit and the DMF was removed in vacuo. The residue was dissolved in EtOAc and washed with water (12×) and brine. Drying (MgSO4), filtration and removal of the solvent in vacuo gave an oil which was purified by silica gel chromatography (EtOAc-hexane) to give ethyl 4-(1,1-dimethylethoxycarbonyl)amino-3-chlorophenoxyacetate (34-4) as an oil. 1H NMR (CDCl3): δ 1.30 (m, 3H), 1.53 (s, 9H), 4.27 (m, 2H), 4.57 (s, 2H), 6.78 (br s, 1H), 6.83 (dd, J=2.8, 8.8 Hz, 1H), 6.96 (d, J=2.8 Hz, 1H), 8.02 (br d, J=8.8 Hz, 1H). This mixture was cooled in an ice bath The mixture was filtered through a frit the DMF was removed in vacuo The residue was dissolved in EtOAc washed with water (12×) and brine Drying (MgSO4), filtration and removal of the solvent in vacuo gave an oil which was purified by silica gel chromatography (EtOAc-hexane)