A solution of 2-(methanesulfonyloxymethyl)pyrazine (5 mmole), (prepared from 2′-(pyrazin-2-yl)styrene according to the procedure in EP 02257, followed by treatment with methanesulfonyl chloride, according to a procedure in Can. J. Chem. 1999, 77 (4) 463 in 20 ml THF was added dropwise to the sodium salt of ethyl N-(diphenylmethylene)glycinate (5 mmole) in 20 ml DMF cooled in an ice bath. The mixture was allowed to warm to room temperature during 4 hrs. The reaction mixture was partitioned between ether and water. The aqueous layer was separated and reextracted with ether (75 ml). The combined ethereal extracts were washed with brine and dried over MgSO4. Evaporation of the solvent afforded a residue which was chromatographed on silica and eluted with acetone:hexane (1:3) to afford 1.27 g (78%) of ethyl 2-(pyrazin-2-yl)-N-(diphenylmethylene)glycinate.
