Benzeneselenol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under a nitrogen atmosphere, 4-(R,S)-acetoxy-3-(S)-(phenoxyacetamido)azetidinone (1.32 g, 4.74 mmol) was dissolved in methylene chloride (9 ml). To this solution was added phenylselenol (1.5 ml, approximately 9.8 mmol), then boron trifluoride-etherate (10 drops). The resultant solution was stirred at room temperature for 20 minutes. The solution was diluted with ethyl acetate and extracted with saturated aqueous sodium bicarbonate solution (2×). The solution was dried over magnesium sulfate, filtered and concentrated in vacuo. The concentrate was absorbed onto silica gel (7 g) and then chromatographed over an additional amount of silica gel (15 g) using a gradient elution of toluene to ethyl acetate. The product-containing fractions gave 4-(R,S)-phenylselenyl)-3-(S)-(phenoxyacetamido)azetidinone. extracted with saturated aqueous sodium bicarbonate solution (2×) The solution was dried over magnesium sulfate filtered concentrated in vacuo The concentrate was absorbed onto silica gel (7 g) chromatographed over an additional amount of silica gel (15 g) a gradient elution of toluene to ethyl acetate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under a nitrogen atmosphere, 4-(R,S)-acetoxy-3-(S)-(phenoxyacetamido)azetidinone (1.32 g, 4.74 mmol) was dissolved in methylene chloride (9 ml). To this solution was added phenylselenol (1.5 ml, approximately 9.8 mmol), then boron trifluoride-etherate (10 drops). The resultant solution was stirred at room temperature for 20 minutes. The solution was diluted with ethyl acetate and extracted with saturated aqueous sodium bicarbonate solution (2×). The solution was dried over magnesium sulfate, filtered and concentrated in vacuo. The concentrate was absorbed onto silica gel (7 g) and then chromatographed over an additional amount of silica gel (15 g) using a gradient elution of toluene to ethyl acetate. The product-containing fractions gave 4-(R,S)-phenylselenyl)-3-(S)-(phenoxyacetamido)azetidinone. extracted with saturated aqueous sodium bicarbonate solution (2×) The solution was dried over magnesium sulfate filtered concentrated in vacuo The concentrate was absorbed onto silica gel (7 g) chromatographed over an additional amount of silica gel (15 g) a gradient elution of toluene to ethyl acetate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under a nitrogen atmosphere, 4-(R,S)-acetoxy-3-(S)-(phenoxyacetamido)azetidinone (1.32 g, 4.74 mmol) was dissolved in methylene chloride (9 ml). To this solution was added phenylselenol (1.5 ml, approximately 9.8 mmol), then boron trifluoride-etherate (10 drops). The resultant solution was stirred at room temperature for 20 minutes. The solution was diluted with ethyl acetate and extracted with saturated aqueous sodium bicarbonate solution (2×). The solution was dried over magnesium sulfate, filtered and concentrated in vacuo. The concentrate was absorbed onto silica gel (7 g) and then chromatographed over an additional amount of silica gel (15 g) using a gradient elution of toluene to ethyl acetate. The product-containing fractions gave 4-(R,S)-phenylselenyl)-3-(S)-(phenoxyacetamido)azetidinone. extracted with saturated aqueous sodium bicarbonate solution (2×) The solution was dried over magnesium sulfate filtered concentrated in vacuo The concentrate was absorbed onto silica gel (7 g) chromatographed over an additional amount of silica gel (15 g) a gradient elution of toluene to ethyl acetate