Diisopropylethylamine → (S)-7-[3-[[(2,3-Dihydro-7-hydroxy-1,4-benzodioxin-2-yl)methyl]amino]propoxy]-2H-1-benzopyran-2-one

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Reaction Conditions

Reaction Steps

(S)-2,3-Dihydro-7-hydroxy-1,4-benzodioxin-2-methanamine (3.53 g, 16.2 mmole), 7-(3-bromopropoxy)coumarin (4.17 g, 14.7 mmole), and diisopropylethylamine (5.00 ml, 28.7 mmole) were combined in 300 ml of DMF and heated at 86° C. for 24 hours under a nitrogen atmosphere. The solvent was then removed in vacuum and replaced with dichloromethane. The mixture was washed with an equal volume of saturated aqueous sodium bicarbonate, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was column chromatographed on 300 g of silica gel using first 75% ethyl acetate/dichloromethane and then 2% methanol/dichloromethane as eluant. The product-containing fractions were concentrated in vacuum and the free base redissolved in warm methanol. Five ml of 4N isopropanolic HCl was added, the mixture was brought to a boil on a hot plate and the solvent gradually replaced with isopropanol. Upon cooling, 2.24 g of the title compound precipitated as an white solid, monohydrochloride, m.p. 245°-248° C.

Provenance & Evidence