2-Ethyl-1-butanol → ethyl 7-(2-ethylbutoxy)-2-(trifluoromethyl)-2H-chromene-3-carboxylate

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Reaction Steps

The polymer bound PPh3 was suspended in THF for 15 min. Ethyl 7-hydroxy-2-(trifluoromethyl)-2H-chromene-3-carboxylate from Example 1a, Step 1 (2.0 g, 6.94 mmole) and 2-ethyl-1-butanol (1.3 mL, 10.35 mmole) were added to above slurry and the mixture was stirred at r.t. for 15 min. Ethyl azodicarboxylate (1.6 mL, 10.35 mmole) was added to above mixture dropwise and the mixture was stirred at room temperature overnight. LCMS indicated product formation and that there was a trace amount of starting material present. The polymer was filtered off through celite pad and the pad was washed with ether. The filtrate was concentrated and the product mixture was suspended in hexane. The suspension was filtered and the filtrate was evaporated and dried in vacuo to afford yellow oil, (2.37 g, 92%): LCMS m/z 394.95 (M+Na). This ester was of suitable purity to use without further purification.

Provenance & Evidence