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 (12.66g) was hydrolysed in 50% dichloromethane-acetone (80ml) with toluene-4-sulphonic acid hydrate (10.22g) in water (25ml) as described in Example 6(b). The crude thiol thus prepared (12.942g), in acetone (50ml) was treated with (2RS,3SR)-2-bromoacetyl-3-methyltetrahydrofuran (6.57g) in acetone (20ml) for 10min. at room temperature. Then potassium carbonate (2.08g) was added and stirring continued for 30min. The solution was diluted with ethyl acetate (200ml), 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 (10.406g, 62%); vmax (CH2Cl2) 3405(br), 1780, 1744, 1683 and 1613cm-1.

Provenance & Evidence