Barium Carbonate → 4-Hydroxyimino-tetrahydro-thiophene-3-carboxylic acid methyl ester

Participants

Reaction Steps

A suspension of 4-oxo-tetrahydro-thiophene-3-carboxylic acid methyl ester (33) (16.96 g, 106 mmol), hydroxylamine hydrochloride (16.96 g, 244 mmol) and barium carbonate (48.16 g, 244 mmol) in methanol (800 mL) was refluxed overnight. The solution was cooled and filtered. The filtrate was concentrated in vacuo. The residue was suspended in water and extracted by ethyl acetate. The combined organic phase was dried over MgSO4 and concentrated to yield 18.30 g (98%) of an isomeric mixture of 4-hydroxyimino-tetrahydro-thiophene-3-carboxylic acid methyl ester as a viscous oil. 1H NMR (400 MHz, CDCl3) δ 3.14-4.11 (m, 7H), 8.17 (m, 1H) ppm. The isomeric mixture was used in the following step without further purification.

Provenance & Evidence