Diethyl Ether → 4-Bromo-3,5-dimethylthiophene-2-carbaldehyde

Temperatur

-35 °C

15.0 G. of 2,4-dibromo-3,5-dimethylthiophene was dissolved in 250 ml. of anhydrous ether and cooled to -70° C. with stirring under argon. 24 Ml. of a 2.4 M sodium of n-butyl lithium was slowly added to the solution and the mixture was warmed to -35° C. for 10 minutes, and then cooled again to -70° C. 7.3 G. of dimethylformamide was added slowly to the mixture and the reaction mixture was warmed to room temperature for 14 hours. The resulting solution was poured into ice water, stirred for 20 minutes and extracted with ethyl ether. The ether extracts were combined, washed with an aqueous solution of 5% sodium carbonate, saturated sodium chloride solution, dried with sodium sulfate, filtered and evaporated to yield 4-bromo-3,5-dimethylthiophene-2-carboxaldehyde, m.p. 44°-45° C.

1. temperaturecooled again to -70° C
2. temperaturethe reaction mixture was warmed to room temperature for 14 hours
3. stirringstirred for 20 minutes
4. extractionextracted with ethyl ether
5. washwashed with an aqueous solution of 5% sodium carbonate, saturated sodium chloride solution
6. dry with materialdried with sodium sulfate
7. filtrationfiltered
8. customevaporated

ORD-Eintrag

ord-326d6568da324d3eb077e50c391191da

Quelldatensatz

uspto-grants-1981_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04256878