Dimethylformamide → HCID 18008982, compound

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Reaction Steps

3-Methyl-1-(3-fluoro-2-naphthyl)-1H-pyrazole-5-carboxylic acid (see Step 1, Example 4) (828 mg, 3.1 mmol) was dissolved in 20 mL dry DCM. To it were added 0.05 mL DMF and oxalyl chloride (0.81 mL, 9.3 mL). The mixture was stirred for 2 hrs. It was evaporated in vacuuo. The residue was dissolved in 30 mL dry dioxane. It was chilled in ice bath. To the stirred cold mixture was added dropwise a chilled solution of sodium azide (0.4 g, 6.2 mmol) in 2 mL water and 1 mL dioxane. Reaction was allowed for 1 hr. It was evaporated in vacuuo. The residue was taken into EtOAc and washed with water ×2. The organic phase was dried and concentrated in vacuuo. The organic residue was then dissolved in 30 mL DMF. To it was added 15 mL water. The mixture was refluxed for 2.5 hrs. It was concentrated in vacuuo and purified using flash column to give 3-methyl-1-(3-fluoro-2-naphthyl)-5-amino-1H-pyrazole (280 mg, 38% overall). Rf 0.45 (1:1 EtOAc:hexane). ES-MS: (M+H)+242.

Provenance & Evidence