Hydrochloric Acid → HCID 131711543, compound

Participants

Reaction Steps

To a solution of 1.774 g of diphenylmethyl α-(3ξ-carboxy-2-phenylacetyl-7-oxo-4-oxa-2,6-diazabicyclo[3.2.0]heptan-6-yl)-α-isopropylideneacetate dissolved in a mixture of 18 ml of benzene and 0.1 ml of N,N-dimethylformamide is added 0.43 ml of oxalyl chloride, and the mixture stirred at room temperature for 30 minutes and then concentrated under reduced pressure. The residue (diphenylmethyl α-(3ξ-chlorocarbonyl-2-phenylacetyl-7-oxo-4-oxa-2,6-diazabicyclo[3.2.0]heptan-6-yl)-α-isopropylideneacetate) is dissolved in 10 ml of methylene chloride and mixed with 15 ml of ether solution of diazomethane, which has been prepared from 1.5 g of nitrosomethylurea, under ice-cooling, and the mixture stirred for 30 minutes. To the resulting solution of diphenylmethyl α-(3ξ-diazoacetyl-2-phenylacetyl-7-oxo-4-oxa-2,6-diazabicyclo[3.2.0]heptan-6-yl)-α-isopropylideneacetate is is added an ether solution of hydrogen chloride until the spot of diazoketone disappears, and the mixture concentrated under reduced pressure. The residue is purified by chromatography on 40 g of silica gel containing 10% water and eluted with benzene containing 10% ethyl acetate to yield 1.59 g of diphenylmethyl α-(3ξ-chloroacetyl-2-phenylacetyl-7-oxo-4-oxa-2,6-diazabicyclo[3.2.0]heptan-6-yl)-α-isopropylideneacetate in 84.7% yield.

Provenance & Evidence