Diethyl Ether → Methyl 3-amino-2-thiophenecarboxylate

2-Methoxycarbonyl-3-oxotetrahydrothiophene (2 g) was dissolved in acetonitrile (20 ml) with heating and stirring. Hydroxylamine hydrochloride (0.8 g) was added to the refluxing solution and the mixture was refluxed for 11/2hour. After cooling, ether (50 ml) was added and the precipitated straw-coloured solid was filtered off. The solid was dissolved in water and basified with 4M ammonia solution and extracted with dichloromethane (2×25 ml). The combined extracts were washed with water and with brine and dried over sodium sulphate. Filtration and evaporation gave an oil which solidified on cooling and was crystallised from petrol ether bp 60°-80° to afford the title compound, 1.34 g (73%); mp 62°-63°.

1. temperaturewith heating
2. temperaturethe mixture was refluxed for 11/2hour
3. temperatureAfter cooling
4. filtrationthe precipitated straw-coloured solid was filtered off
5. dissolutionThe solid was dissolved in water and basified with 4M ammonia solution
6. extractionextracted with dichloromethane (2×25 ml)
7. washThe combined extracts were washed with water and with brine
8. dry with materialdried over sodium sulphate
9. filtrationFiltration and evaporation
10. customgave an oil which
11. temperatureon cooling
12. customwas crystallised from petrol ether bp 60°-80°

ORD record

ord-e432bb8ef66748f1b818b97ff335a9af

Source dataset

uspto-grants-1989_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04847386