Ethyl Bromide → 3-Ethyl 2-Methyl 6-oxooctahydroisoquinoline-2,3(1H)-dicarboxylate

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Reaction Conditions

Reaction Steps

In Scheme X, Step A, the compound of structure (i) is esterified by reaction with a compound of formula Et-Br (where Et represents an ethyl group) to provide the intermediate of compound (i-b). For example 2-methoxycarbonyl-6-oxodecahydroisoquinoline-3-carboxylic acid is dissolved in acetonitrile and treated with triethylamine and bromoethane. The reaction is heated at 50° C. for about 3 hours, cooled and partitioned between 50:50 ethyl acetate/heptane and 1N HCl. The organic phase is isolated and washed 3 times with water, saturated sodium bicarbonate, brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum to provide ethyl-2-methoxycarbonyl-6-oxodecahydroisoquinoline-3-carboxylate, the compound of structure (i-b). This crude material may then be purified under standard conditions well known in the art. For example, the crude material is dissolved in 10% ethyl acetate/heptane and applied to a plug of silica gel (10 g in 10% ethyl acetate/heptane). The plug is eluted with, 10% ethyl acetate/heptane, 15% ethyl acetate/heptane, and 25% ethyl acetate/heptane. The eluents are combined and concentrated under vacuum to provide the purified compound of structure (i-b).

Provenance & Evidence