4-Hydroxybenzaldehyde → HCID 54101020, compound

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Reaction Steps

A solution of 5,6,7,8-tetrahydro-2-methyl-3-quinolinecarboxylic acid ethyl ester (2.19 g) and 4-hydroxybenzaldehyde (1.32 g, 11 mmol) in acetic anhydride (6.5 ml) is heated at reflux temperature for 18 hours. The solution is evaporated, the residue dissolved in tetrahydrofuran and crude 8-[[4-(acetyloxy)phenyl)methylene]-5,6,7,8-tetrahydro-2-methyl-3-quinolinecarboxylic acid ethyl ester is precipitated with water to yield 3.4 g. Purification on silica gel (250 g) with 9:1 Skelly B:ethyl acetate gives pure 8-[[4-(acetyloxy)phenyl)-methylene]-5,6,7,8-tetrahydro-2-methyl-3-quinolinecarboxylic acid ethyl ester (2.76 g), m.p. 112° C., after ethanol crystallization.

Provenance & Evidence