FMOC-lysine can be produced by a one-step reaction using lysine and 9-fluorenylmethyl chloroformate as starting materials in the following steps:
A methylene chloride solution of lysine was added to a clean and dry round-bottomed flask, cooled directly to -5 to 5C, then 35 mL of triethylamine was added and stirred at that temperature for half an hour. A dichloromethane solution of configured methyl 9-fluorenyl chloroformate (89.4 g/200 mL) was added dropwise to the reaction system, controlled at -5 to 5 C, and then stirred for forty minutes. HCI solution (300 mL) of 3N was added dropwise to the reaction system and the reaction temperature was controlled at 0 to 10C. The reaction solution was then stirred at 0 to 10C for half an hour, left to stand, and layered. The organic phase was washed with water (300 mL) and then dichloromethane was evaporated under reduced pressure at 30-35 C. Petroleum ether (500 mL) was then added and stirred. The solution was stirred and cooled to 0C and FMOC-lysine began to precipitate from the solution, stirring was continued at 0C for forty minutes and then filtered. The filter cake was washed with petroleum ether (100 mL) and dried under vacuum at 30 to 35C to give a white FMOC-lysine solid. The yield is usually in the range of 60 to 80%.
