Ethyl formate → Racemic Ethyl 6,7-Dimethoxy-3-hydroxymethylene-2-methyl-4-oxo-1,2,3,4-tetrahydroquinoline-1-carboxylate

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Reaction Steps

To sodium ethoxide, freshly prepared from 4.8 g. of sodium hydride and 6.0 ml. of ethanol was added a solution of 14.7 g. of ethyl 6,7-dimethoxy-2-methyl-4-oxo-1,2,3,4-tetrahydroquinoline-1-carboxylate and 19.8 ml. of ethyl formate in 150 ml. of benzene, over a 45 min. period. The reaction mixture was stirred at room temperature for 3 hrs. and then it was poured onto 250 ml. of ice water. The layers were separated, and the organic layer was extracted with 1N sodium hydroxide solution. The combined aqueous phases were washed with benzene, and then they were added dropwise to 250 ml. of 12N hydrochloric acid. This caused the product to separate in the form of an oil. Recrystallization of this oil from hexane produced 15.4 g. (96% yield) of the title compound, m.p. 98°-101° C. Further recrystallization from hexane raised the melting point to 129°-130° C.

Provenance & Evidence