2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 5-Bromo-2-chloro-4-(thiophen-2-yl)pyrimidine

Temperatur

-78 °C

A solution of thiophene (3.3 g, 39 mmol) in THF (100 mL) was cooled to −78° C. n-Butyllithium (2.5 M in hexane, 24 mL, 59 mmol) was added and the mixture stirred at −78° C. for 1 h. 2-Chloro-5-bromopyrimidine (7.5 g, 39 mmol) was added and the mixture stirred at −78° C. for 1 h. DDQ (17.7 g, 78 mmol) was added with stirring, followed by the addition of methanol (5 mL). The mixture stirred for 1 h and was then warmed to 0° C. and then to RT. The reaction mixture was poured into 0.5 M sodium ascorbate (aq) solution (100 mL), and allowed to stir for 1 h. The mixture was treated with saturated aqueous potassium carbonate solution (50 mL), and extracted with ethyl acetate. The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated. The residue was purified via column chromatography on silica gel (eluting with 100% dichloromethane) to afford 5-bromo-2-chloro-4-(thiophen-2-yl)pyrimidine as a yellow solid. MS m/z=276 [M+H]+. Calc'd for C8H4BrClN2S: 275.

1. additionwas added
2. stirringthe mixture stirred at −78° C. for 1 h
3. stirringwith stirring
4. stirringThe mixture stirred for 1 h
5. temperaturewas then warmed to 0° C.
6. customto RT
7. stirringto stir for 1 h
8. extractionextracted with ethyl acetate
9. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
10. filtrationfiltered
11. concentrationconcentrated
12. customThe residue was purified via column chromatography on silica gel (eluting with 100% dichloromethane)

ORD-Eintrag

ord-956ec0dd64c84921ac4f8255ee6d96fa

Quelldatensatz

uspto-grants-2013_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08557996B2