Sulfuric Acid → HCID 14189817, compound

Participants

Reaction Conditions

Reaction Steps

10.0g (24.3 mmoles) of BOC--Nle--OH.DCHA are added to a mixture of 75 ml of ether and 25 ml of 2 n aqueous sulfuric acid, and the mixture is shaken until the dissolution is complete. The phases are separated, and the etheral solution is washed again with 25 ml of 2 n aqueous sulfuric acid and water. The etheral solution is evaporated in vacuo. The resulting 5.44 g of oily residue and 4.42 g (24 mmoles) of pentafluorophenol are dissolved in 30 ml of ethyl acetate, the solution is cooled to 0° C., and 4.63 g (22.5 mmoles) of dicyclohexyl carbodiimide are added. The suspension is allowed to stand at a cold place for 1 hour, thereafter it is filtered, and the filtrate is evaporated in vacuo. The residue is dissolved in 50 ml of n-hexane and the solution is washed with 5×20 ml of 5% aqueous sodium bicarbonate solution and 2×20 ml of water. The organic solution is dried and evaporated in vacuo. The oily residue solidifies upon cooling. 8.12 g (91%) of BOC--Nle--OPFP are obtained; m.p.: 55°-57° C., [α]D : -26.8° (c=1.0, in dioxane), Rf2 =0.80Rf4 =0.85.

Provenance & Evidence