4-Methyl-1-naphthol → 2,6-Dimethyl-2-morpholinophenylbenzochromene

Beteiligte Stoffe

Reaktionsschritte

2-p-Morpholinophenylpropargyl alcohol (3C) (8 g) and 4-methyl-1-naphthol (5 g) were dissolved in hot toluene (300 cm3) and the solution added to dry acidic alumina (200 g) in a flask fitted with a condenser. The mixture was heated (20 minutes) on a water bath, cooled and filtered. The residual alumina was extracted with chloroform (3×100 cm3). The combined organic filtrates and extracts were evaporated and the residual oil was purified by chromatography on acidic alumina (100 g) using a 1:20 mixture of dichloromethane and petroleum as eluant. The heliochromic fraction was separated and the solvent removed, leaving a dark brown oil. Two further chromatographic separations failed to improve the quality of the benzochromene (3D; R=Me). The brown oil darkens in air but its n.m.r. spectrum indicates less than 5% impurities.

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