ethyl 7-(bromomethyl)-6-chloro-2-(trifluoromethyl)-2H-chromene-3-carboxylate → ethyl 6-chloro-7-[(4-methylpyridin-2-yl)methyl]-2-(trifluoromethyl)-2H-chromene-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

The bromo (4-methylpyridin-2-yl)magnesium (10.4 mL, 2.6 mmole) was diluted by 5 mL THF and the solution was cooled to −78° C. ZnCl2 (340 mg, 2.5 mmole) was added to above solution and the mixture was slowly warmed to r.t and heated to 50 OC for 3 hrs. The mixture was cooled to −78° C. again and ethyl 7-(bromomethyl)-6-chloro-2-(trifluoromethyl)-2H-chromene-3-carboxylate from Example 16, Step 3 (1.0 g, 2.5 mmol) was added to above mixture and followed by PdCl2(PPh3)2 (18 mg, 0.025 mmole). The mixture was warmed to 50° C. for 3 hrs. LCMS indicated that around 40% product was formed. The reaction was quenched with 1 N HCl and extracted with EtOAc. The organic layer was washed with brine and dried over MgSO4. The filtrate was concentrated to afford the crude product, which was purified by RPHPLC eluted with 10 to 95% ACN in water with 0.05% TFA to give 50 mg the desired product as a brown oil (yield 5%), which had suitable purity to use without further purification.

Provenance & Evidence