Methanesulfonic Acid → Isatin

HRID 2375513Notes

Reaction equation

HRID 2375513 reaction equation
C[C:2]1[C:7](C)=[CH:6][CH:5]=[CH:4][C:3]=1[NH:9][C:10](=[O:14])[CH:11]=NO.CS(O)(=O)=[O:17]>>[NH:9]1[C:3]2[C:4](=[CH:5][CH:6]=[CH:7][CH:2]=2)[C:11](=[O:17])[C:10]1=[O:14]

Participants

3

Reactant 2

HCID 6395Methanesulfonic AcidHCID 6399797N-(2,3-Dimethylphenyl)-2-(hydroxyimino)acetamide

Product 1

HCID 7054Isatin

Procedure

Intermediate 3 (20 g, 0.1 mol) was added in small portions, with stirring, to 80 mL CH3SO3H at 70° C.-80° C. in one hour. After the addition was complete it was left at the same temperature for 15 more minutes and was then poured onto crushed ice in a beaker. Additional ice was added until the outside of the beaker felt cold to the touch. The precipitate was then collected and dissolved in 1N aqueous NaOH. Neutralization with acetic acid precipitated impurities which were removed by filtration, and acidification (HCl) of the filtrate gave isatin intermediate 4 as a solid (12.8 g, 70%). 1H NMR (400 MHz, DMSO-D6) δ ppm 2.09 (s, 3H) 2.27 (s, 3H) 6.89 (d, J=7.58 Hz, 1H) 7.25 (d, J=7.58 Hz, 1H) 11.02 (s, 1H).

Workup

  1. additionAfter the addition
  2. waitwas left at the same temperature for 15 more minutes
  3. additionwas then poured
  4. customonto crushed ice in a beaker
  5. additionAdditional ice was added until the outside of the beaker
  6. customThe precipitate was then collected
  7. dissolutiondissolved in 1N aqueous NaOH
  8. customNeutralization with acetic acid precipitated impurities which were removed by filtration, and acidification (HCl) of the filtrate

Sources & evidence

ORD record
ord-a02228819747461c9327d0cb61303227
Source dataset
uspto-grants-2008_12
Patent number
US07465799B2

Reaction notes

Loading…