
ETHYL 4-HYDROXY-6-METHOXYQUINOLINE-3-CARBOXYLATE synthesis
- Product Name:ETHYL 4-HYDROXY-6-METHOXYQUINOLINE-3-CARBOXYLATE
- CAS Number:77156-78-6
- Molecular formula:C13H13NO4
- Molecular Weight:247.25

83507-70-4

77156-78-6
A solution was prepared from diethyl 2-[(4-methoxyanilino)methylene]malonate (CAS: 83507-70-4, 71.4 g, 0.24 mol) in 150 mL of diphenyl ether. The reaction system was placed in a metal bath and slowly heated to 243 °C and maintained at this temperature for 3 hours. During the reaction, 15 mL of liquid was distilled. Upon completion of the reaction, the mixture was cooled to room temperature and subsequently dissolved by adding 250 mL of hexane. After stirring the mixture for 3 hours, a filtration operation was performed. The resulting solid was washed with hexane and dried to give ethyl 4-hydroxy-6-methoxyquinoline-3-carboxylate (25.0 g, 0.10 mol, 41% yield), the purity of which meets the requirements for direct use in subsequent reactions. The structure of the product was confirmed by 1H-NMR (CDCl3) and LC-MS: 1H-NMR (CDCl3) δ= 1.28 (t, 3H), 3.85 (s, 3H), 4.21 (q, 2H), 7.34 (dd, 1H), 7.55-7.62 (m, 2H), 8.49 (s, 1H); LC-MS: Rt = 1.17 min ; MS: m/z = 248 [M + 1]+.
Yield:77156-78-6 78%
Reaction Conditions:
with diphenyl ether-biphenyl eutectic in ethanol; for 0.5 h;Heating / reflux;
Steps:
4.a
A solution of 4-methoxyaniline (4Og, 0.32 mole) and diethyl ethoxymethylenemalonate (65 mL, 0.32 mole) in Dowtherm A (500 mL) was heated at reflux in a flask fitted with side-arm and condenser, and heating was continued until all the ethanol had distilled off (ca. 0.5 hr). The solution was cooled and pentane was added to give a sticky precipitate. The solvents were decanted off and the residue was treated with more pentane and allowed to stand overnight. The solid was filtered off and washed well with pentane to give the title compound (62.4 g; 78%, contains traces of Dowtherm A).
References:
WO2006/81289,2006,A2 Location in patent:Page/Page column 19

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