Dimethylformamide → Methyl 5-carbamoyl-1-(2-ethoxyethyl)-4-nitro-1h-pyrazole-3-carboxylate

Participants

Reaction Steps

Oxalyl chloride (1.2 mL, 13.76 mmol) and N,N-dimethylformamide (39 μL) were added to a solution of the carboxylic acid of step 2 (1.33 g, 4.63 mmol) in dichloromethane (20 mL) and the reaction mixture stirred at room temperature for 2 hours. The reaction mixture was concentrated in vacuo and azeotroped from dichloromethane (3×50 mL). The product was dissolved in tetrahydrofuran (50 mL), cooled in an ice bath, treated with 0.88 ammonia solution (10 mL) and stirred for 18 hours at room temperature. The mixture was concentrated in vacuo and the residue partitioned between dichloromethane (200 mL) and water (50 mL). The organics phase was dried over magnesium sulphate and concentrated in vacuo to yield the nitro product. 1H NMR (DMSO-D6, 400 MHz) δ: 1.06 (t, 3H), 3.40 (m, 2H), 3.77 (m, 2H), 3.84 (s, 3H), 4.38 (m, 2H), 8.35 (m, 1H), 8.46 (m, 1H). MS APCI+m/z 287 [MH]+.

Provenance & Evidence