3-amino-7-bromo-2,3-dihydrochromen-4-one;hydrochloride

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: N-Methylmorpholine (2.14 mL, 19.4 mmol) was added to a mixture of (S)-1-(tert-butoxycarbonyl)pyrrolidine-2-carboxylic acid (1.93 g, 8.98 mmol) and 2-(1H-7-Azabenzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (3.41 g, 8.98 mmol), in N,N-dimethylformamide (6 mL). After 5 min solution of 3-amino-7-bromochroman-4-one hydrochloride (2.5 g, 8.9 mmol) and N-methylmorpholine (2.14 mL, 19.4 mmol) in N,N-dimethylformamide (6 mL) was added. After 1 hour the mixture was diluted with ethyl acetate (100 mL) and was with water (2×25 mL), saturated sodium bicarbonate (25 mL), saturated ammonium chloride (25 mL) and dried over sodium sulfate. The mixture was filtered and the solvent was removed under reduced pressure. The residue was subjected to flash chromatography with eluant of (10% methanol in ethylacetate) and hexane. The product containing fractions were combined and the solvent was removed under reduced pressure to provide (2S)-tert-butyl 2-(7-bromo-4-oxochroman-3-ylcarbamoyl)pyrrolidine-1-carboxylate (3.23 g, 7.35 mmol, 84%). dried over sodium sulfate The mixture was filtered the solvent was removed under reduced pressure The product containing fractions the solvent was removed under reduced pressure