Hydrochloric Acid → 3-Methylisoxazole-5-carboxylic acid

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 1N hydrochloric acid. The mixture was extracted with ethyl acetate (3×35 mL) and the combined extractions were washed with brine (1×50 mL), dried over magnesium sulfate, and filtered. The filtrate was concentrated in vacuo to yield 3-methyl-isoxazole-5-carboxylic acid as a white solid (660 mg, 90%). The solid was used without purification in the next reaction.

1. customThe reaction was transferred to a separatory funnel
2. extractionThe mixture was extracted with ethyl acetate (3×35 mL)
3. extractionthe combined extractions
4. washwere washed with brine (1×50 mL)
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-0f7b983b359f491da0240ca7b8a533c0

Source dataset

uspto-grants-2011_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07951950B2