Sodium Bicarbonate → 3-bromo-2-pyridin-2-yl-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole

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Reaction Steps

Stir a mixture of 2-(pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylic acid (Preparation 3; 2 g, 8.7 mmol), sodium bicarbonate (3.3 g, 38.4 mmol) and N-bromosuccinamide (1.7 g, 9.6 mmol) in DMF (50 mL) at room temperature for 2 h. Dilute the crude mixture with 50 mL of water and 100 mL of ethyl acetate. Separate the ethyl acetate layer, extract with saturated brine, dry over anhydrous sodium sulfate, filter, and evaporate to a solid mass. Purify by MPLC (SiO2, 50% ethyl acetate-hexane) to obtain the title compound (1.62 g, 70%) as a cream solid. MS ES+ m/e 264 (M+1), MS ES+ m/e 266 (M+2).

Provenance & Evidence