Potassium Carbonate → 4-Methoxybenzyl (2RS)-2-Hydroxy-2-[(3R,4R)-3-phenylacetamido-4-[(2RS, 3SR)-3-methyltetrahYdrofuran-2-ylcarbonylmethylthio]azetidin-2-on-1-yl]acetate

Participants

Reaction Steps

4-Methoxybenzyl (2RS) -2-hydroxy-2- [(1R, 5R) -3-benzyl-4-thia-2,6-diazabicyclo[3.2.0]hept-2-en-7-on-6-yl]acetate (12.66 g) was hydrolysed in 50% dichloromethane-acetone (80 ml) with toluene-4-sulphonic acid hydrate (10.22 g) in water (25 ml) as described in Example 6 (b). The crude thiol thus prepared (12.942 g), in acetone (50 ml) was treated with (2RS,3SR)-2-bromoacetyl-3-methyltetrahydrofuran (6.57 g) in acetone (20 ml) for 10 min. at room temperature. Then potassium carbonate (2.08 g) was added and stirring continued for 30 min. The solution was diluted with ethyl acetate (200 ml), washed with water (2x), brine and then dried. Remvoal of solvent gave a yellow gum. Flash chromatography on silica gel eluting with 50, 60, 70, 80 and then 90% ethyl acetate-hexane afforded the title compound as a pale yellow foam (10.406 g, 62%); νmax (CH2Cl2) 3405(br), 1780, 1744, 1683 and 1613 cm-1.

Provenance & Evidence