Sodium Thiosulfate → 7-Amino-4-bromo-2-methylisoindolin-1-one

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Reaction Steps

NBS (2.3 g, 12.96) was added to a cold (−8° C. to −10° C.) solution of 7-amino-2-methyl-2,3-dihydro-1H-isoindol-1-one (Compound 17E, 2 g, 12.4 mmol) in DCM (40 mL) and the mixture stirred at −8° C. to −10° C. for 1 h. A solution of 10% aq. sodium thiosulfate (30 mL) was then added to the reaction mixture and stirring was continued for another 20 minutes. The layers were separated and the aqueous layer was extracted with DCM (2×20 mL). The combined organic extracts were washed with water (3×40 mL) and brine (30 mL), and the organic layer was dried (Na2SO4) and concentrated in vacuo to yield 3.2 g of crude product. This material was triturated with ethyl acetate (10 mL) to give 2.2 g of pure 7-amino-4-bromo-2-methyl-2,3-dihydro-1H-isoindol-1-one (yield: 74%). 1H NMR (CDCl3 400 MHz): δ 3.14 (s, 3H), 4.20 (s, 2H), 5.20 (bs, 2H), 5.49 (d, 1H, J=8.4 Hz), 5.79 (d, 1H, J=8.4 Hz).

Provenance & Evidence