2-FLUORO-5-NITRO-BENZOIC ACID TERT-BUTYL ESTER synthesis

Yield:-

Reaction Conditions:

dmap in tetrahydrofuran;tert-butyl alcohol; for 25 h;

Steps:

180

Reference Example 180 tert-Butyl 2-fluoro-5-nitrobenzoate [Show Image] N,N-dimethylaminopyridine (801 mg) and di-tert-butyl dicarbonate (9.54 g) were added to a suspension of 2-fluoro-5-nitrobenzoic acid (4.04 g) in tetrahydrofuran (60 mL) and stirred for 11 hours. Then, tert-butanol (60 mL) was added thereto and stirred for 24 hours. The reaction solution was filtered and the filtrate was concentrated under reduced pressure. The residue was suspended in ethyl acetate (500 mL) and the suspension was filtered. The filtrate was concentrated under reduced pressure and the residue was purified by a silica gel column chromatography (developing solvent: hexane/ethyl acetate = 20/1) to obtain the title compound (4.652 g) as a light-yellow oil. ¹H NMR (400 MHz, CDCl₃) δ 8.77-8.75 (m, 1H), 8.39-8.35 (m, 1H), 7.31-7.27 (m, 1H), 1.53 (s, 9H).

References:

EP1690863,2006,A1 Location in patent:Page/Page column 177