Boron trifluoride → HCID 20522869, compound

Participants

Reaction Steps

Ethyl pyruvate (1.00 g, 0.0086 m), 3,4-dimethoxyphenylethanol (1.57 g, 0.0086 m), and, 1 ml of BF3 etherate are stirred at 25° C. in 20 ml of nitromethane for 45 minutes. The mixture is dissolved in methylene chloride and extracted with aqueous sodium bicarbonate. The organic phase is dried (sodium sulfate), concentrated, and chromatographed on silica gel to give 1.4 g of 6,7-dimethoxy-1-methyl-1-carboethoxyisochroman. A 0.5 g sample of this is dissolved in ether and treated with 100 mg of LAH. After 10 minutes, the mixture is quenched with ethyl acetate and partitioned between 1 N aqueous sodium hydroxide and CH2Cl2. The organic phase yields 0.34 g of 6,7-dimethoxy-1-methyl-1-hydroxymethylisochroman. This is dissolved in THF and treated sequentially with sodium hydride and then o-tetrahydropyranyl chloroethanol. The adduct, upon treatment with acid and water, yields 2-[(7,8-dimethoxy-1-methyl-isochroman-1-yl)methoxy]ethanol. In the manner of Preparation 7, this can be converted to its benzenesulfonates ##STR21## Furthermore, 2-[(1-methylisochroman-1-yl)methoxy]ethanols, with various substituents on the isochroman ring, can be prepared by using the appropriate phenyl ethanols whose substituents, R1 -R5 (vide supra), are analogous to those substituents of the isochromans of Table 3.

Provenance & Evidence