Hydrochloric Acid → ethyl 3-amino-5-[4-(ethoxycarbonyl)phenyl]-1H-pyrrole-2-carboxylate

To a suspension of methyl 4-(2-cyano-1-{[(4-methylphenyl)sulfonyl]oxy}vinyl)benzoate (17.5 g) and diethyl aminomalonate hydrochloride (10.36 g) in a mixed solvent of ethanol (165 mL)-tetrahydrofuran (80 mL) was added dropwise a solution (50 mL) of 20% sodium ethoxide in ethanol under ice-cooling. After stirring under ice-cooling for 1 hr, the mixture was stirred at room temperature for 21 hr. the reaction mixture was poured into ice water (400 mL) and adjusted to pH 7 with 1N hydrochloric acid. The organic solvent was evaporated under reduced pressure, and the residue was extracted with ethyl acetate (250 mL×3). The organic layers were combined, washed with saturated brine (150 mL), and dried over anhydrous magnesium sulfate. After concentration under reduced pressure, the residue was purified by silica gel column chromatography (eluent, hexane:ethyl acetate=2:1→1:1) and the obtained solid was recrystallized from ethyl acetate to give the title compound (4.76 g).

1. temperaturecooling
2. temperaturecooling for 1 hr
3. stirringthe mixture was stirred at room temperature for 21 hr
4. customThe organic solvent was evaporated under reduced pressure
5. extractionthe residue was extracted with ethyl acetate (250 mL×3)
6. washwashed with saturated brine (150 mL)
7. dry with materialdried over anhydrous magnesium sulfate
8. concentrationAfter concentration under reduced pressure
9. customthe residue was purified by silica gel column chromatography (eluent, hexane:ethyl acetate=2:1→1:1)
10. customthe obtained solid was recrystallized from ethyl acetate

ORD record

ord-f247aca2bfa54aee8ed9bc83774397b9

Source dataset

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08178543B2