Pyridine → N-methoxy-N-methyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a cooled (5-6° C.), stirred suspension of crude potassium 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxylate (0.82 g, 4.3 mmol) in dichloromethane (15 mL), containing N,N-dimethylformamide (0.1 mL, 1.3 mmol), is added, dropwise, oxalyl chloride (0.6 mL, 6.9 mmol). The reaction is exothermic with gas evolution. After the addition, the ice-bath is removed to allow the reaction mixture to stir at room temperature. After 3 hours, the solution is added to a stirred, cooled (10-12° C.) suspension of N,O-dimethylhydroxylamine hydrochloride (0.67 g, 6.9 mmol) in dichloromethane (7 mL) containing pyridine (1.7 mL, 21 mmol). After 40 minutes at room temperature, dichloromethane (35 mL) and water (25 mL) are added. The two layers are separated. The organic layer is extracted with water (2×25 mL), dried over anhydrous sodium sulfate, filtered and concentrated under diminished pressure to give 0.75 g (89% yield) of N-methoxy-N-methyl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-2-carboxamide as a brown solid.

Provenance & Evidence