Methanesulfonic Acid → HCID 178465170, compound

Participants

Reaction Steps

Boc-Tyr(Bn)-D-Leu-Leu-Arg(Ts)-Pro-NHEt was prepared from Boc-D-Leu-Leu-Arg(Ts)-Pro-NHEt obtained in Example 2 and Boc-Tyr(Bn) by the same procedure as Example 2. To a solution composed of this compound (0.46 g) and dichloromethane (5 ml), methanesulfonic acid (0.42 g) was added at room temperature, and the resulting mixture was stirred at room temperature for 1 hour, thereby the Boc group was removed (reaction conversion ratio: 99.9%). After the reaction, 5% aqueous sodium carbonate solution (5 ml) was added thereto, and the resulting mixture was stirred for 15 minutes, and then, the aqueous layer was separated off. After Boc-Ser (Bn) (0.19 g) and HOBt monohydrate (0.12 g) were added to the obtained dichloromethane solution of Tyr(Bn)-D-Leu-Leu-Arg(Ts)-Pro-NHEt, the reaction solution was cooled with ice. Then, EDC hydrochloride (0.15 g) was added thereto, and the resulting mixture was stirred for 1 hour. Subsequently, the temperature of the mixture was raised to room temperature and the mixture was stirred for 15 hours, thereby a condensation reaction was carried out (reaction conversion ratio: 99.9%).

Provenance & Evidence