Reacción #1995048

Ecuación de reacción

ethyl acetoacetate

dimethylformamide dimethylacetal

p-toluenesulfonic acid

2-ethylisothiourea hydrobromide

→

solid

Rendimiento 62.7%

4-Methyl-2-ethylsulfanyl-pyrimidine-5-carboxylic acid ethyl ester

Rendimiento 62.7%

Disolventes

N,N-dimethylformamide

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaAfter cooling to rt
2. 2
   workup.ADDITIONwas added
3. 3
   TemperaturaAfter heating the at 100° C. for 18 h
4. 4
   Temperaturathe mixture was cooled to rt
5. 5
   Concentraciónconcentrated
6. 6
   Otroto give a crude residue, which
7. 7
   Otrowas purified by FCC (EtOAc/hexanes)

Procedimiento

A mixture of ethyl acetoacetate (6.37 mL, 50.0 mol), dimethylformamide dimethylacetal (8.94 g, 75.0 mmol), and catalytic p-toluenesulfonic acid was heated at 100° C. for 2 h. After cooling to rt, the mixture was diluted with N,N-dimethylformamide (DMF; 50 mL) and 2-ethylisothiourea hydrobromide (9.10 g, 50.0 mmol) was added. After heating the at 100° C. for 18 h, the mixture was cooled to rt and concentrated to give a crude residue, which was purified by FCC (EtOAc/hexanes) to give 7.1 g (61%) of a solid. 1H NMR (CDCl3): 8.97-8.91 (m, 1H), 4.43-4.35 (m, 2H), 3.24-3.15 (m, 2H), 2.81-2.72 (m, 3H), 1.47-1.35 (m, 6H).

Fuente