Ammonium Chloride → 6-(7-hydroxy-6,7-dihydro-5H-pyrrolo[1,2-c]imidazol-7-yl)-2-naphthamide

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Reaction Conditions

Reaction Steps

6-Bromo-2-naphthoic acid (1.51 g) was dissolved in dry THF (50 ml) and the mixture was cooled in a liquid nitrogen/diethyl ether bath to −100° C. With stirring the mixture, an n-butyl lithium hexane solution (1.6M; 7.88 ml) was added dropwise at not more than −95° C. over 5 min. The mixture was stirred at −100° C. for 30 min and at −80° C. for 10 min. Thereafter, the mixture was cooled again to −100° C. and a solution of 5,6-dihydro-7H-pyrrolo[1,2-c]imidazol-7-one (0.61 g) in dry THF (11 ml) was added dropwise at not more than −90° C. over 5 min. The mixture was stirred at same temperature for 30 min and warmed to −70° C. over 30 min. A saturated aqueous ammonium chloride solution (25 ml) was added to stop the reaction. After stirring the mixture for 10 min, ethyl acetate (50 ml) was added for partitioning. The organic layer was removed and the aqueous layer was concentrated to dryness. The resulting residue was purified by flash column chromatography and the objective fraction was dissolved in methanol. This solution was concentrated, ether was added to the precipitated powder for filtration and dried to give the title compound (180 mg) as a colorless powder. The mother liquid was concentrated to give a residue (449 mg) containing the title compound.

Provenance & Evidence