Ethyl 4-fluorobut-2-ynoate → (S)-2-(4-cyclohexyl-phenoxymethyl)-5-fluoromethyl-2,3-dihydro-oxazolo[3,2 a]-pyrimidin-7-one

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Reaction Steps

To a solution of (S)-5-(4-cyclohexyl-phenoxymethyl)-4,5-dihydro-oxazol-2-ylamine (0.464 g, 1.69 mmol), (see Example 28) in ethanol (25 mL) was added 4-fluoro-but-2-ynoic acid ethyl ester (0.22 g, 1.69 mmol) (see Poulter, J Org Chem 1981, 46, 1532). The reaction mixture was heated at reflux for 14 hrs and then gradually cooled to room temperature. The solvent was removed under vacuum, and the residue purified by flash column chromatography (silica gel, 0-2% 7N NH3 in MeOH /CH2Cl2) to afford 0.358g of (S)-2-(4-cyclohexyl-phenoxymethyl)-5-fluoromethyl-2,3-dihydro-oxazolo[3,2 a]-pyrimidin-7-one. [α]D25 −28.20 (c 0.5, CHCl3).

Provenance & Evidence