Hydrochloric Acid → (3R,5R,6R)-6-amino-3-(p-nitrobenzyloxycarbonyl)-7-oxo-3-(2-oxo-3-ureidoimidazolidin-1-yl)-4-thia-1-azabicyclo[3.2.0]heptane

Participants

Reaction Steps

In a mixed solvent consisting of 30 ml of water and 30 ml of methanol was suspended 5.00 g of (3R,5R,6R)-6-amino-3-(3-amino-2-oxoimidazolidin-1-yl)-3-(p-nitrobenzyloxycarbonyl)-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane. To suspension was added 2.96 ml of concentrated hydrochloric acid with water cooling. To the resulting solution was added 1.36 g of sodium cyanate in 10 minutes, and the mixture was stirred at room temperature for 30 minutes. The reaction mixture was filtered. To the filtrate were added 50 ml of ethyl acetate and 50 ml of water. The aqueous layer was separated. The organic layer was extracted three times each with 30 ml of water. The extracts were combined with the aqueous layer obtained previously. The combined aqueous solution was adjusted to pH 6.9 with sodium hydrogencarbonate. The solvent was removed by distillation under reduced pressure. The residue was dehydrated by four times of azeotropy with ethanol. To the resulting residue was added a mixed solvent consisting of 50 ml of methylene chloride and 10 ml of methanol. The insolubles were removed by filtration. The filtrate was concentrated under reduced pressure. The residue was purified by column chromatography (eluant: chloroform/methanol=10/1 to 5/1) to obtain 4.29 g (yield: 77.9%) of (3R,5R,6R)-6-amino-3-(p-nitrobenzyloxycarbonyl)-7-oxo-3-(2-oxo-3-ureidoimidazolidin-1-yl)-4-thia-1-azabicyclo[3.2.0]heptane.

Provenance & Evidence