Bromine → 3-Bromo-2-hydroxy-cyclohex-1-enecarboxylic acid ethyl ester

Temperature

0 °C

Ethyl 2-oxocyclohexanecarboxylate (5.0 g, 29 mmol, 4.7 mL) was dissolved in diethyl ether (5 mL) and cooled to 0° C. under N2. Bromine (4.6 g, 29 mmol, 4.2 mL) was added dropwise over 15 min and the reaction mixture was allowed to warm to room temperature over 90 min. The mixture was slowly poured into ice-cold saturated aqueous sodium carbonate solution (40 mL) and extracted with ethyl acetate (3×40 mL). The combined organic layers were dried and concentrated in vacuo to afford 5.96 g (81%) of 3-bromo-2-hydroxy-cyclohex-1-enecarboxylic acid ethyl ester (29) as a pale yellow oil which was used in the next step without purification. The structure was confirmed by 13C NMR (75 MHz, DMSO-d6) δC 14.14, 17.65, 21.77, 32.02, 59.95, 60.83, 99.70, 166.33, 172.81.

1. temperatureto warm to room temperature over 90 min
2. extractionextracted with ethyl acetate (3×40 mL)
3. customThe combined organic layers were dried
4. concentrationconcentrated in vacuo

ORD record

ord-066851851e714bfab37a92d130f18372

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09314541B2