Lawesson's reagent → (S)-tert-butyl 2-methyl-5-thioxopiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a suspension of (S)-tert-butyl 2-methyl-5-oxopiperazine-1-carboxylate (7.0 g, 32.7 mmol) was added Lawesson's reagent (6.9 g, 16.7 mmol) and the reaction mixture was heated to 80° C. for 2 hours. The reaction mixture was cooled to room temperature, concentrated onto silica gel and purified by flash column chromatography (0-100% 10% 4M NH3 in MeOH in DCM) to provide the desired compound (5.7 g, 76%). 1H NMR (400 MHz, DMSO) δ 10.64 (s, 1H), 4.48 (d, J=18.9 Hz, 1H), 4.31-4.14 (m, 1H), 4.06 (d, J=18.9 Hz, 1H), 3.49-3.41 (m, 1H), 3.13 (ddd, J=13.7, 4.8, 2.9 Hz, 1H), 1.43 (s, 9H), 1.07 (d, J=6.6 Hz, 3H).

Provenance & Evidence