Acetic Anhydride → 3-Acetyl-7-chloro-2(3H)-benzothiazolone

HRID 223389Notes

Reaction equation

HRID 223389 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([N+:8]([O-])=O)[C:3]=1[S:11][CH2:12]C(O)=O.[C:16]([O-])(=[O:18])[CH3:17].[Na+].C(OC(=O)C)(=[O:23])C>>[C:16]([N:8]1[C:4]2[CH:5]=[CH:6][CH:7]=[C:2]([Cl:1])[C:3]=2[S:11][C:12]1=[O:23])(=[O:18])[CH3:17]

Participants

4

Reactant 3

HCID 7918Acetic AnhydrideHCID 517045Sodium AcetateHCID 20522282[(2-Chloro-6-nitro-phenyl)-thio]acetic acid

Product 1

HCID 205222793-Acetyl-7-chloro-2(3H)-benzothiazolone

Conditions

Temperature
100 °C

Procedure

A mixture of 79.0 gm (0.32 mol) of [(2-chloro-6-nitro-phenyl)-thio]acetic acid, 150.0 gm (1.83 mol) of anhydrous sodium acetate and 600 ml of acetic acid anhydride was heated for 30 minutes at 100° C. The acetic acid anhydride was distilled off in an aspirator vacuum, the residue was stirred with 1 liter of water, and the precipitate was collected by suction filtration. After purification by chromatography on silica gel, using dichloromethane/ethyl acetate (volume ratio 1:1) for elution, the product was recrystallized from ethanol. 19.2 gm (26% of theory) of colorless crystals with a melting point of 74° C. were obtained.

Workup

  1. distillationThe acetic acid anhydride was distilled off in an aspirator vacuum
  2. filtrationthe precipitate was collected by suction filtration
  3. customAfter purification by chromatography on silica gel
  4. washfor elution
  5. customthe product was recrystallized from ethanol
  6. custom19.2 gm (26% of theory) of colorless crystals with a melting point of 74° C. were obtained

Sources & evidence

ORD record
ord-7023f71818cc4125960e4c64e402728a
Source dataset
uspto-grants-1982_10
Patent number
US04353919

Reaction notes

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