Thionyl Chloride → Rac-benzyl-{1-[[2-(o-fluorobenzoyl)-4-nitrophenyl]carbamoyl]ethyl}carbamate

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Reaction Steps

50 g of carbobenzoxy-DL-alanine are dissolved in 400 ml of absolute tetrahydrofuran, treated dropwise while cooling with ice with 30 g of thionyl chloride and stirred for 40 minutes, a suspension of 50 g of 2-amino-5-nitro-2'-fluorobenzophenone in 200 ml of absolute tetrahydrofuran then being rapidly added dropwise. Subsequently, the mixture is stirred at room temperature for 18 hours, the solution is concentrated and the residue is treated with ice and 10% sodium bicarbonate solution. The mixture is extracted with methylene chloride, the organic solution is dried with sodium sulphate, filtered and concentrated. The residue is crystallised from ethanol and yields rac-benzyl-{1-[[2-(o-fluorobenzoyl)-4-nitrophenyl]carbamoyl]ethyl}carbamate which is further processed directly as the crude product.

Provenance & Evidence