Diisopropylethylamine → 7-[3-[(7-Methoxy-2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl)amino]propoxy]chromen-4-one

Participants

Reaction Conditions

Reaction Steps

2,3-Dihydro-7-methoxy-1,4-benzodioxin-2-methanamine hydrochloride (4.0 g, 17 mmole), 7-(3-bromopropoxy)chromen-4-one (4.9 g, 17 mmole) and diisopropylethylamine (15.1 ml, 87 mmole) were combined in 150 ml of DMF and heated at 80° C. for 24 hours under a nitrogen atmosphere. The solvent was then removed and replaced with dichloromethane. The mixture was washed with an equal volume of saturated aqueous sodium bicarbonate, with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuum. The residue was chromatographed on a silica gel column using first dichloromethane and then 5% methanolic dichloromethane as eluents. The fractions containing material with Rf=0.59 on silica gel tlc (chloroform/methanol/ammonia=95/5/1) were combined, concentrated, and the residue was dissolved in 50% methanol/dichloromethane. The mixture was then treated with 4N isopropanolic HCl until the solution was 3 in pH and crystallized by triturating with ether. Two further recrystallizations gave 0.3 g of title compound as a yellow solid hydrochloride, quarter hydrate, m.p. 155°-157° C.

Provenance & Evidence