Diisopropylethylamine → Ethyl 3-(Trifluoromethyl)pyrazole-4-carboxylate

To a suspension of hydrazine hydrochloride (10 g, 147 mmol) in EtOH (500 mL), DIPEA (45.3 mL, 267 mmol) was added slowly at −20° C. and stirred for 10 minutes. Then 2-[1-ethoxy-meth-(E)-ylidene]-4,4,4-trifluoro-3-oxo-butyric acid ethyl ester (Preparation 96 Step 1, 32 g, 133.33 mmol) was added to above solution and the resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was concentrated under reduced pressure and residue was partitioned between EtOAc (200 mL) and water (50 mL). The organic layer was washed with water (25 mL), dried (Na2SO4) and evaporated in vacuo. The crude material was purified by silica gel column chromatography eluting with Hexane:EtOAc 90:10 to afford the title compound as off white solid (43%, 13 g).

1. additionwas added slowly at −20° C.
2. stirringthe resulting mixture was stirred at room temperature for 16 hours
3. concentrationThe reaction mixture was concentrated under reduced pressure and residue
4. customwas partitioned between EtOAc (200 mL) and water (50 mL)
5. washThe organic layer was washed with water (25 mL)
6. dry with materialdried (Na2SO4)
7. customevaporated in vacuo
8. customThe crude material was purified by silica gel column chromatography
9. washeluting with Hexane:EtOAc 90:10

ORDレコード

ord-18b821e71bac48ef9446089e8e737330

出典データセット

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US09163021B2