Hydrochloric Acid → 1,5-Dimethyl-3-(trifluoromethyl)-1H-pyrazole-4-carbaldehyde

Temperature

-78 °C

Dissolve 4-bromo-1,5-dimethyl-3-trifluoromethyl-1H-pyrazole (0.30 g, 1.23 mmol) in tetrahydrofuran (14.7 mL). Cool to −78° C. and add 1.7 M t-butyllithium in pentane (2.9 mL) dropwise. Stir for 3 min. at −78° C. and then add dimethylformamide (669 μL, 8.64 mmol). Stir for thirty min. at −78° C., then warm to 0° C. over 2 hr. Add 2 N hydrochloric acid (12.3 mL) and stir at room temperature for one hr. Separate layers and extract aqueous layer 2 times with DCM. Dry combined organic layers (magnesium sulfate), filter, concentrate and purify (silica gel chromatography eluting with 0:100 to 15:85 ethyl acetate:hexanes), to give the title preparation (79 mg, 33%). GC-MS: m/z=192 [M+].

1. stirringStir for thirty min. at −78° C.
2. temperaturewarm to 0° C. over 2 hr
3. stirringstir at room temperature for one hr
4. extractionSeparate layers and extract aqueous layer 2 times with DCM
5. customDry
6. filtrationfilter
7. concentrationconcentrate
8. custompurify
9. wash(silica gel chromatography eluting with 0:100 to 15:85 ethyl acetate:hexanes)
10. customto give the title
11. custompreparation (79 mg, 33%)

ORD record

ord-803c5b118d0840efa936bf8fc0bf6ab5

Source dataset

uspto-grants-2012_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08202873B2