Triethylamine → 4-Methoxybenzyl (RS)-2-hydroxy-2-[4-[(2RS,5SR)-5-methoxycarbonyltetrahydrofuran-2-ylcarbonylmethylthio)-3-phenylacetamidoazetidin-2-on-1-yl]acetate

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Reaction Steps

4-Methoxybenzyl glyoxylate hydrate (1.50 g) in dichloroethane (30 ml) was heated at reflux for 1 h using a Dean and Stark apparatus for heavy entrainers. The mixture was cooled to room temperature and then a solution of (3R,4R)-4-[(2RS,5SR)-5-methoxycarbonyltetrahydrofuran-2-ylcarbonylmethylthio]-3-phenylacetamidoazetidin-2-one (2.208 g) in dichloroethane (20 ml) was added followed by triethylamine (0.1 ml). The mixture was stirred at room temperature for 1 h and then the solvents were evaporated. The title compound was obtained as a mixture of isomers (2.66 g) by column chromatography of the residue using gradient elution (silica gel, 1:1 hexane:ethyl acetate going to neat ethyl acetate); νmax (CHCl3) 3412, 1776, 1741 and 1681 cm-1.

Provenance & Evidence