2-Methylbenzenesulfonic acid hydrate → (R)-2-acetamido-3-ethoxycarbonyl-2-penten-4-olide

HRID 1033838Notes

Reaction equation

HRID 1033838 reaction equation
[NH2:1][C:2]1[C:3]([O:5][C@H:6]([CH3:13])[C:7]=1[C:8]([O:10][CH2:11][CH3:12])=[O:9])=[O:4].[OH2:14].[C:15]1([CH3:25])C(S(O)(=O)=O)=CC=CC=1>C(OC(=O)C)(=O)C>[C:15]([NH:1][C:2]1[C:3]([O:5][C@H:6]([CH3:13])[C:7]=1[C:8]([O:10][CH2:11][CH3:12])=[O:9])=[O:4])(=[O:14])[CH3:25]

Participants

4

Reactant 2

HCID 124969952-Methylbenzenesulfonic acid hydrateHCID 22851708(R)-2-amino-3-ethoxycarbonyl-2-penten-4-olide

Product 1

HCID 22851706(R)-2-acetamido-3-ethoxycarbonyl-2-penten-4-olide

Reagents, catalysts & solvents 1

HCID 7918Acetic AnhydrideSolvent

Conditions

Temperature
40 °C

Procedure

12.04 g of (R)-2-amino-3-ethoxycarbonyl-2-penten-4-olide are dissolved in 48 ml of acetic anhydride, 125 mg of toluenesulphonic acid monohydrate are added and the whole is stirred overnight at 40° C. The mixture is concentrated by evaporation, dissolved in ethyl acetate and washed with water. The ethyl acetate is distilled off and the residue is recrystallised from ethyl acetate/cyclohexane, [α]D20 =+62.3° (3% in CHCl3), m.p. 119°-122° C.

Workup

  1. concentrationThe mixture is concentrated by evaporation
  2. dissolutiondissolved in ethyl acetate
  3. washwashed with water
  4. distillationThe ethyl acetate is distilled off
  5. customthe residue is recrystallised from ethyl acetate/cyclohexane, [α]D20 =+62.3° (3% in CHCl3), m.p. 119°-122° C.

Sources & evidence

ORD record
ord-523f0648441e4a9ab422680dbd6ca173
Source dataset
uspto-grants-1994_05
Patent number
US05312914

Reaction notes

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