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

HRID 55457Notes

Reaction equation

HRID 55457 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-26f9d88d33cc4916a5ce56fe1bb398c6
Source dataset
uspto-grants-1997_04
Patent number
US05625059

Reaction notes

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