Triethylamine → HCID 86686408, compound

(S)-6-Benzyloxycarbonylamino-4-(tert-butoxycarbonyl)-4-azaheptan-1-ol (380 g, 1.04 mol) and triethylamine (147 g, 1.45 mol) were dissolved in methylene chloride (5.0 L). The resulting solution was cooled to 0° C., to which a solution of methanesulfonyl chloride (143 g, 1.25 mol) in methylene chloride (0.1 L) was added at an internal temperature of 5° C. or below. Subsequently, the reaction mixture was stirred at room temperature for 16 hours. After confirming the disappearance of the starting materials by TLC, purified water was added to the reaction mixture for extraction. The resulting organic layer was washed with 0.5 N hydrochloric acid, saturated aqueous sodium bicarbonate, and saturated brine, and then dried over anhydrous sodium sulfate. The resulting mixture was filtered and concentrated under reduced pressure to give the target product as a yellow oil (425 g, yield 92.0%). Despite the fact that the compound thus obtained was refrigerated, the degradation reaction proceeded, revealing that this compound was unstable.