3-Thiophenecarboxylic acid, tetrahydro-4-oxo-, methyl ester → 4-Hydroxyimino-tetrahydro-thiophene-3-carboxylic acid methyl ester

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Reaction Steps

Compounds of structure (II) were prepared by using 4-amino-thiophene-3-carboxylic acid methyl ester, as depicted by formula (21), as a starting material. To make this compound, methyl thioglycolate was reacted with methyl acrylate to yield intermediate 3-methoxycarbonylmethylsulfanyl-propionic acid methyl ester, depicted by formula (18), which was cyclized to 4-oxo-tetrahydro-thiophene-3-carboxylic acid methyl ester, depicted by formula (19). This intermediate was reacted with hydroxylamine hydrochloride to yield 4-hydroxyimino-tetrahydro-thiophene-3-carboxylic acid methyl ester, depicted by formula (20), which yielded 4-amino-thiophene-3-carboxylic acid methyl ester hydrochloride, depicted by formula (21), as shown in Scheme 10.

Provenance & Evidence