Diisopropylethylamine → (S)-tert-butyl 4-(5-(tert-butyldimethylsilyloxy)-4-(3-(2-chloro-3-fluorobenzyl)-1-methylureido)pentanoyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a solution of (S)-tert-butyl 4-(5-(tert-butyldimethylsilyloxy)-4-(methylamino)pentanoyl)piperazine-1-carboxylate (16 g, 37.3 mmol) and DIEA (1.3 mL, 7.46 mmol) in THF (180 mL) was added 4-nitrophenyl 2-chloro-3-fluorobenzylcarbamate (12 g, 37.3 mmol). The reaction mixture was stirred at RT for 2 h and concentrated. The residue was purified on silica gel using a mixture of EtOAc and hexanes to give (S)-tert-butyl 4-(5-(tert-butyldimethylsilyloxy)-4-(3-(2-chloro-3-fluorobenzyl)-1-methylureido)pentanoyl)piperazine-1-carboxylate (14.3 g, 62.4% for three steps). LRMS (M+H) m/z 615.3.

Provenance & Evidence