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ChemicalBook CAS DataBase List 5-(4-Bromo-phenyl)-3-methyl-isoxazole-4-carboxylic acid

5-(4-Bromo-phenyl)-3-methyl-isoxazole-4-carboxylic acid synthesis

7synthesis methods
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Yield:91182-60-4 96%

Reaction Conditions:

Stage #1: 5-(4-bromophenyl)-3-methylisoxazole-4-carboxylic acid ethyl esterwith lithium hydroxide;water in tetrahydrofuran at 20;
Stage #2: with oxalic acid in water; pH=~ 4;

Steps:

AH.4

To a stirred solution of ester (3.2 g, 0.010M) in THF/H2O (79/35 ml) was added lithium hydroxide (2.4 g, 0.010M). The reaction mixture was stirred at room temperature for over night and the solvent, THF was removed from the reaction mixture under vacuum. The resulting mass was diluted with water and washed with diethyl ether (2×50 ml). Then the aqueous solution was acidified with sat. Oxalic acid (PH4) and was extracted with ethyl acetate (2×75 ml). The combined organic layer was dried over anhydrous sodium sulphate, concentrated under vacuum to give the pure product 2.8 g (96%). 1H NMR (DMSO-d6): δ 2.52 (3H, s), 7.37 (2H, dd), 7.91 (2H, dd), 12.42 (1H, br s). 13C NMR (DMSO-d6) δ 12.0, 110.0, 126.6, 127.2, 131.7, 132.5, 162.4, 164.4, 172.7. MH+=282.

References:

US2006/287287,2006,A1 Location in patent:Page/Page column 31-32