Benzoic acid, 3-nitro-4-(1-piperazinyl)-, 1,1-diMethylethyl ester synthesis

Yield:1012060-12-6 70.7%

Reaction Conditions:

with potassium carbonate in N,N-dimethyl-formamide at 120; for 6 h;

Steps:

7.b

A mixture of piperazine(451 mg, 5.2 mmol), tert-butyl 4-fluoro-3-nitro-benzoate (211 mg, 0.9 mmol) and K₂CO₃ (234 mg, 1.7 mmol) in DMF(IO ml) was stirred at 12O⁰C for 6 hours. The mixture was poured into water, and extracted with ethyl acetate. The organic phase was washed with water (100 ml), concentrateded in vacuo. The residue was purified with flash column chromatography on silica gel eluting with 25% ethyl acetate/petroleum ether to provide 0202 (190 mg, 70.7%). LC-MS: 308 [M+l]⁺. ¹H NMR (CDCl₃): δ 1.58 (s, 9H), 1.84 (s, IH), 3.01 (m, 4H), 3.12 (m, 4H), 7.03 (d, J= 6.0 Hz, IH), 8.02 (dd, J= 2.1, 6.0 Hz, IH), 8.33 (d, J= 2.1 Hz, IH).

References:

WO2009/36051,2009,A1 Location in patent:Page/Page column 57