Lawesson's reagent → tert-Butyl (S)-5-thioxo-2-pyrrolidinecarboxylate

HRID 481235Notes

Reaction equation

HRID 481235 reaction equation
O=[C:2]1[NH:6][C@H:5]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:4][CH2:3]1.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:23])=CC=1>C1C=CC=CC=1>[S:23]=[C:2]1[NH:6][C@H:5]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:4][CH2:3]1

Participants

4

Reactant 2

HCID 87949Lawesson's reagentHCID 10888648tert-Butyl 5-oxo-L-prolinate

Product 1

HCID 14416882tert-Butyl (S)-5-thioxo-2-pyrrolidinecarboxylateYield 191.1%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

To a solution of t-butyl pyroglutamate (1a) (10.12 g, 54.6 mmol) in benzene (250 mL), was added Lawesson's reagent (11.05 g, 27.3 mmol). The mixture was stirred at reflux for 15.5 h, then concentrated. The resultant residue was purified by flash chromatography (0 to 2 to 3 to 4% MeOH/CHCl3) to afford 10.50 g (95%) of the title compound, 1b. 1H NMR (300 MHz, CDCl3) δ7.27 (br s, 1H), 4.46-4.39 (m, 1H), 3.03-2.84 (m, 2H), 2.58-2.46 (m, 1H), 2.37-2.23 (m, 2H), 1.49 (s, 9H).

Workup

  1. temperatureat reflux for 15.5 h
  2. concentrationconcentrated
  3. customThe resultant residue was purified by flash chromatography (0 to 2 to 3 to 4% MeOH/CHCl3)

Sources & evidence

ORD record
ord-0cbea4cb5de04d0485f0239638812b25
Source dataset
uspto-grants-2003_11
Patent number
US06653295B2

Reaction notes

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