ChemicalBook CAS DataBase List 3-METHYLISOXAZOLE-5-CARBOXYLIC ACID

3-METHYLISOXAZOLE-5-CARBOXYLIC ACID synthesis

11synthesis methods

Product Name:3-METHYLISOXAZOLE-5-CARBOXYLIC ACID
CAS Number:4857-42-5
Molecular formula:C5H5NO3
Molecular Weight:127.1

63366-79-0 Synthesis

5-Isoxazolecarboxylicacid,3-methyl-,ethylester(6CI,7CI,9CI)

63366-79-0
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$45.00/50mg

4857-42-5
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$17.00/250mg

Yield:4857-42-5 90%

Reaction Conditions:

Stage #1: 3-methylisoxazole-5-carboxylic acid ethyl esterwith sodium hydroxide;water in tetrahydrofuran;methanol at 20; for 18 - 20 h;
Stage #2: with hydrogenchloride in tetrahydrofuran;methanol;water; pH=2;

Steps:

A round bottom flask with magnetic stirrer was charged with 3-methyl-isoxazole-5- carboxylic acid ethyl ester (900 mg, 5.8 mmol) in tetrahydrofuran (2.0 mL). To the reaction was added a solution of sodium hydroxide (465 mg, 11.6 mmol) in water (2 mL), followed by methanol (4 mL). The reaction was stirred at room temperature for 18 - 20 hours under an argon atmosphere. The reaction was transferred to a separatory funnel and the pH adjusted to 2 via addition of IN hydrochloric acid. The mixture was extracted with ethyl acetate (3 x 35 mL) and the combined extractions were washed with brine (1 x 50 mL), dried over magnesium sulfate, and filtered. The filtrate was concentrated in vacuo to yield S-methyl-isoxazole-S-carboxylic acid as a white solid (660 mg, 90%). The solid was used without purification in the next reaction.

References:

WO2006/91674,2006,A1 Location in patent:Page/Page column 79