4-Fluorophenol → (7RS,9aSR)-7-(4-Fluorophenoxy)methyl-2-(2-cyano-4-fluorophenyl)-2,3,4,6,7,8,9,9a-octahydro-1H-pyrido[1,2-a]pyrazine

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Reaction Steps

A solution of 0.51 g (1.8 mmol) of (7RS,9aSR)-7-hydroxymethyl-2-(2-cyano-4-fluorophenyl)-2,3,4,6,7,8,9,9a-octahydro-1H-pyrido[1,2-a]pyrazine, 0.555 g (2.12 mmol) of triphenylphosphine, and 0.296 g (2.64 mmol) of 4-fluorophenol in 8 mL of dry THF was treated with 0.368 g (2.12 mmol) of diethyl azodicarboxylate and stirred at ambient temperature for 24 h. The mixture was diluted with ether, and 1M HCl was added until a gummy residue formed. The layers were separated and the aqueous layer was washed with ether (3×). The aqueous layer was combined with the gummy residue and dissolved in a mixture of ethyl acetate and 10% ammonium hydroxide, the layers were separated and the aqueous layer was extracted with more ethyl acetate (2×). The organic layers were evaporated, the residue dissolved in chloroform, washed with 1M NaOH (3×), dried (magnesium sulfate), filtered and evaporated. The product was dissolved in absolute ethanol, filtered and evaporated to give 0.21 g of the title compound. mp (.HCl) 235–240° C. HRMS calcd for C22H23F2N3O: 383.1809, found: 383.1796.

Provenance & Evidence