1,4-Dioxane hydrochloride → O-benzyl-L-tyrosine

Participants

Reaction Steps

To the above compound (II) (1.0 g) was added under ice-cooling 4N-hydrogen chloride/dioxane solution (4.5 ml) and the mixture was stirred at room temperature for 30 minutes. Hexane (30 ml) was added to this solution and the precipitated crystalline substance was collected by filtration, washed with ether and then dried under reduced pressure to give quantitatively 4-benzyloxy-L-phenylalanine 4-cis/trans-methylcyclohexylamide hydrochloride (III). On the other hand, triethylamine (0.6 ml) was added to a solution of trans-4-(t-butyloxycarbonyl)aminomethylcyclohexylcarboxylic acid (0.62 g) dissolved in dry tetrahydrofuran (30 ml) and ethyl chlorocarbonate (0.25 g) was added under ice-cooling, followed by stirring for 30 minutes. To this solution were added the above compound (III) (0.73 g) and triethylamine (1 ml), and the mixture was stirred at room temperature for 3 hours. After evaporation of the solvent, the residue was extracted with ethyl acetate, washed with water and dried to give 0.2 g of N-[trans-4-(t-butyloxycarbonyl)aminomethylcyclohexylcarbonyl]-4-benzyloxyl-L-phenylalanine 4-cis/trans-methylcyclohexylamide (IV). To the above compound (IV) (0.2 g) was added under ice-cooling 4N-hydrogen chloride/dioxane solution (0.5 ml) and the mixture was stirred at room temperature for 30 minutes. Hexane (20 ml) was added to this solution and the precipitated crystalline substance was collected by filtration, washed with ether and then dried under a reduced pressure to give 0.1 g of N-(trans-4-aminomethylcyclohexylcarbonyl)-4-benzyloxy-L-phenylalanine 4-cis/trans-methylcyclohexylamide hydrochloride.

Provenance & Evidence