N-bromobutanimide → tert-butyl 5-bromo-6-cyclohexyl-4H-thieno[3,2-b]pyrrole-2-carboxylate

Temperatur

0 °C

A solution (0.2 M) of 6-cyclohexyl-4H-thieno[3,2-b]pyrrole-2-carboxylic acid (prepared as described in example 14, step 8) in THF was treated with tert-butyl N,N′-diisopropylimidocarbamate (2 eq.). The reaction mixture was heated to reflux for 1 h. After cooling down, the mixture was filtered trough a pad of silica gel and washed with AcOEt. Evaporation under reduced pressure of the filtrate gave a residue that was dissolved in DCM. The resulting solution (0.2 M) was cooled at 0° C. and treated with NBS (1 eq.). The reaction mixture was stirred at 0° C. for 1 h, then it was quenched with aqueous Na2S2O3 (saturated solution) and extracted with AcOEt. The combined organic phase was washed with aqueous Na2S2O3 (saturated solution) and brine and dried. Evaporation of the solvent under reduced pressure afforded the title compound (37%) as a solid.

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 1 h
3. temperatureAfter cooling down
4. filtrationthe mixture was filtered trough a pad of silica gel
5. washwashed with AcOEt
6. customEvaporation under reduced pressure of the filtrate
7. customgave a residue that
8. customit was quenched with aqueous Na2S2O3 (saturated solution)
9. extractionextracted with AcOEt
10. washThe combined organic phase was washed with aqueous Na2S2O3 (saturated solution) and brine
11. customdried
12. customEvaporation of the solvent under reduced pressure

ORD-Eintrag

ord-1df4ca85c96f422b947e708aae27cc8a

Quelldatensatz

uspto-grants-2010_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07781431B2