Methyl 3-amino-2-thiophenecarboxylate → Methyl 3-nitrothiophene-2-carboxylate

Temperature

2.5 °C

To a stirring solution of methyl 3-aminothiophene-2-carboxylate (5 g, 31.8 mmol) in Conc. HCl (4.77 ml) was added aq. solution of sodium nitrite (2.195 g, 31.8 mmol) slowly at 0-5° C. Reaction mixture was stirred at 0-5° C. for 1 h. To this was added aq. solution of sodium tetrafluoroborate (5.24 g, 47.7 mmol) in one lot. After 30 min. precipitated product was filtered. The product was added to the stirring suspension of copper bronze (6.06 g, 95 mmol) and sodium nitrite (26.3 g, 382 mmol) in water (100 ml). Reaction mixture was stirred at 25° C. for 1 h. Reaction mixture was diluted with water and EtOAc and filtered through Hyflow bed. The organic layer was separated and distilled out to get crude product which was column purified using 0-5% EtOAC in hexane to get titled compound as light yellow solid in 63% yield.

1. customReaction mixture
2. customAfter 30 min. precipitated product
3. filtrationwas filtered
4. customReaction mixture
5. stirringwas stirred at 25° C. for 1 h
6. customReaction mixture
7. filtrationfiltered through Hyflow bed
8. customThe organic layer was separated
9. distillationdistilled out
10. customto get crude product which
11. custompurified

ORD record

ord-6133b796f30b426dab1c686e7820c60b

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09394300B2