Potassium Bromide → HCID 86762555, compound

Participants

Reaction Conditions

Reaction Steps

5% NaHCO3 (16 mL) was added to a 250 mL RB flask. A solution of cis-/trans-4-(1-tert-Butoxycarbonylamino-2-hydroxy-ethyl)cyclohexanecarboxylic acid propyl ester (1-5, prepared according to Example 1) (1.65 g, 1 eq) in acetone (37 mL) was added. The mixture was cooled to 0° C. with an ice-H2O bath. KBr (119.00, 60 mg, 0.1 eq) was added, followed by the addition of TEMPO (825 mg, 1.05 eq). Bleach (12.5 mL) was added dropwise. The reaction mixture was stirred at 0° C. for 1 hour. Another portion of bleach (4.7 mL) was added. The reaction mixture stir at 0° C. for 1 hour, followed by the addition of 5% NaHCO3 (19 mL). TLC and LC/MS indicated the absence of starting material. Acetone was removed under vacuum. The aqueous mixture was extracted with Et2O (2×30 mL). The aqueous layer was acidified to pH=3 with 10% HCl while cooling with ice-H2O bath, and then extracted with EtOAc (3×50 mL). The combined EtOAc was washed with brine. After drying over Na2SO4 and filtration, the filtrate was concentrated under vacuum to give 4-(tert-Butoxycarbonylamino-carboxy-methyl)-cyclohexanecarboxylic acid propyl ester (2-1) 1.71 g in 99.4% yield. The 1H NMR (DMSO-d6) data is depicted in FIG. 17.

Provenance & Evidence