Water → S-4-(tert-butyl-dimethylsilyloxy)benzyl 4-tert-butoxycarbonylpiperazine-1-thiocarboxylate

Participants

Reaction Conditions

Reaction Steps

to a stirred solution of 4-(tert-butyldimethylsilyloxy)-benzenemethanethiol (10.5 g, 41 mmol) and triethylamine (69 mmol, 9.6 mL) in THF (500 mL) at 0° C. was added 4-tert-butoxycarbonyl-1-chlorocarbonylpiperazine (8.56 g, 34 mmol) and DMAP (6.9 mmol, 0.84 g). The reaction mixture was warmed to 50° C. and stirred for 3 h then poured into water (500 mL) and extracted with EtOAc (2×250 mL). The combined organic extracts were washed with water (250 mL) then brine (500 mL), then dried (MgSO4) and concentrated to reveal a brown oil. Chromatography [SiO2: 90/10, hexane/EtOAc)] gave the product as a yellow oil which crystallised on standing (13.4 g, 85%): m.p. 53–54° C. 1H-NMR (400 MHz, CDCl3): 0.18 (6H, s), 0.96 (9H, s), 1.46 (9H, s), 3.42–3.51 (8H, m), 4.12 (2H, s), 6.75 (2H, d, J=8.5 Hz) and 7.18 (2H, d, J=8.5 Hz).

Provenance & Evidence