Bromide ion → Methyl 5-[(4-nitro-1h-pyrazol-1-yl)methyl]-2-furoate

Beteiligte Stoffe

Reaktionsschritte

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of 4-nitro-1H-pyrazole (6.22 g, 55.0 mmol) in acetone (130 mL) was treated with 5-chloromethyl-furan-2-carboxylic acid methyl ester (9.61 g, 55.0 mmol) followed by K2CO3 (38.04 g, 275.2 mmol) and TBA bromide (3.55 g, 11.0 mmol). The reaction mixture was stirred at rt for 2 h before being quenched with water (500 mL), extracted with EA (3×100 mL) and the combined org. extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (50:50 hept-EA) gave the title compound as a yellowish solid. TLC: rf (50:50 hept-EA)=0.35. LC-MS-conditions 02: tR=0.88 min. 1H NMR (400 MHz, CDCl3) δ 3.91 (s, 3H), 5.39 (s, 2H), 6.59 (d, J=3.3 Hz, 1H), 7.17 (d, J=3.3 Hz, 1H), 8.09 (s, 1H), 8.23 (s, 1H).

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