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methyl 6,7-dichloro-2-hydroxyquinoline-3-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
3,4-Dichloro-6-aminobenzaldehyde (2.85 g, 15 mmol) was stirred with dimethylmalonate (10 ml) at 140 C. for 20 h. The mixture was diluted with ethyl ether (100 ml). The precipitate was collected, washed twice with ethyl ether and dried in vacuo to give 2.86 g of methyl 6,7-dichloro-2-hydroxyquinoline-3-carboxylate.
Example 9 (R)-alpha-Amino-6,7-dichloro-3-(phosphonomethyl)-2-quinolinepropanoic acid 3,4-Dichloro-6-nitrobenzaldehyde (4.40 g, 20 mmol) was dissolved in 50% aqueous ethanol (200 ml) at 50-60 C. and the solution was added to a solution of iron(II) sulfate heptahydrate (27.8 g, 100 mmol) in water (200 ml) at 90 C. Concentrated (25%) aqueous ammonia (50 ml) was added in several portions with intensive stirring while the temperature was kept close to the boiling point. The mixture was refluxed for 5-10 min. and cooled. The precipitate was filtered off and washed with ethanol. The filtrate was concentrated in vacuo until most of the ethanol was removed. The resulting precipitate was collected, washed with water and dried in vacuo at 40-50 C. to give 3.3 g of 3,4-dichloro-6-aminobenzaldehyde.
With hydrogenchloride; sodium methylate; In N-methyl-acetamide; methanol;
EXAMPLE 3 6,7-Dichloro-2-(1H)-quinolinone-3-sulfonic acid, sodium salt A suspension containing 2.00 g (10.5 mmol) of <strong>[163458-94-4]4,5-dichloro-2-aminobenzaldehyde</strong> (prepared according to the procedure described by A. Cordi et al., Bioorg. Med. Chem., 1995, 2, 129-141), 4.12 g (21 mmol) of ethoxysulfonylacetic acid ethyl ester (prepared according to the procedure described by M. Bordeau et al., Bull. Soc. Chim. Fr., 1986, 3, 413-417 and J. I. Trujillo et al., Tetrahedron Lett., 1993, 46, 7355-7358), 4 ml (21 mmol) of 5.25M sodium methanolate in methanol and 25 ml of anhydrous methanol, is stirred for 72 hours at room temperature. The methanol is evaporated under vacuum and the reaction medium is neutralized by adding dropwise 1N hydrochloric acid. The precipitate is filtered and taken up in 10 ml of dimethylformamide at high temperature. The mixture is allowed to return to room temperature and the white solid is filtered. Melting point:>300 C. The compounds of the following examples are prepared according to the procedure described in Example 1 from the corresponding starting materials: