Methyl iodide → 2,3,5,6-Tetrafluorotoluene

Temperatur

-60 °C

A solution of n-butyllithium in hexane (1.6 M, 62.5 ml) was added dropwise to a well stirred solution of 1,2,4,5-tetrafluorobenzene (15.0 g) in dry tetrahydrofuran (150 ml) maintained at a temperature of -60° C. under an atmosphere of dry argon. When the addition was complete the mixture was stirred at -45° C. for 2 hours and then methyl iodide (14.2 g) was added dropwise whilst the temperature was kept at -45° C. After a period of 30 minutes the mixture was allowed to warm to the ambient temperature, poured into distilled water and the mixture extracted with diethyl ether (2×50 ml), and the extracts dried over anhydrous magnesium sulphate. After filtering the solution was concentrated by evaporation of the solvents at atmospheric pressure. The residual oil was distilled and the fraction boiling in the range 115°-122° C. at atmospheric pressure (6.2 g) collected, identified by n.m.r. and gas chromatographic analysis as consisting of ca. 95% of the required 2,3,5,6-tetrafluorotoluene and ca. 5% of 2,3,5,6-tetrafluoro-1,4-xylene.

1. additionWhen the addition
2. customwas kept at -45° C
3. waitAfter a period of 30 minutes the mixture was allowed
4. temperatureto warm to the ambient temperature
5. additionpoured
6. distillationinto distilled water
7. extractionthe mixture extracted with diethyl ether (2×50 ml)
8. dry with materialthe extracts dried over anhydrous magnesium sulphate
9. filtrationAfter filtering the solution
10. concentrationwas concentrated by evaporation of the solvents at atmospheric pressure
11. distillationThe residual oil was distilled
12. customboiling in the range 115°-122° C. at atmospheric pressure (6.2 g)
13. customcollected

ORD-Eintrag

ord-190995229d0445419a832525ac58d9bd

Quelldatensatz

uspto-grants-1983_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04385070