HCID 53836446, compound → HCID 53668564, compound

Participants

Reaction Steps

In 300 ml of methanol was dissolved 19 g of (S)-4-(N-benzyloxycarbonyl-O-methyl-L-tyrosyl)-3-methoxycarbonylmethyl-2-oxopiperazine-1-acetic acid. To the solution was added 2.5 g of 10% palladium-carbon, and the mixture was stirred under hydrogen atomosphere for 1.5 hour. The catalyst was filtered off, and the filtrate was concentrated under reduced pressure. The residue was dissolved in a mixture of 200 ml of water and 50 ml of 1,4-dioxane, to which was added 7.36 ml of triethylamine. To the mixture was added, under ice-cooling, 8.4 g of di-t-butyl dicarbonate. The reaction mixture was adjusted to pH 2 with 5% potassium hydrogensulfate, followed by extraction with ethyl acetate and drying over anhydrous sodium sulfate. The extract solution was concentrated under reduced pressure to give 16.5 g of the title compound in a crude state as a colorless powdery product.

Provenance & Evidence