Sulfuric Acid → 5-methyl-1H,6H,7H,8H-pyrrolo[2,3-g]indazole-7,8-dione

HRID 1907133Notes

Reaction equation

HRID 1907133 reaction equation
S(=O)(=O)(O)[OH:2].O/N=[CH:8]/[C:9]([NH:11][C:12]1[CH:20]=[C:19]2[C:15]([CH:16]=[N:17][NH:18]2)=[CH:14][C:13]=1[CH3:21])=[O:10]>>[CH3:21][C:13]1[CH:14]=[C:15]2[C:19](=[C:20]3[C:8](=[O:2])[C:9](=[O:10])[NH:11][C:12]=13)[NH:18][N:17]=[CH:16]2

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 87408991HCID 87408991, compound

Product 1

HCID 1358740205-methyl-1H,6H,7H,8H-pyrrolo[2,3-g]indazole-7,8-dione

Conditions

Temperature
70 °C

Procedure

To concentrated sulphuric acid (119 ml) was added portionwise 2-[(E)-hydroxyimino]-N-(5-methyl-1H-indazol-6-yl)-acetamide (34.7 g, 146.3 mmol). The addition was strongly exothermic and the internal temperature was maintained at 70° C. with an ice bath. At the end of the addition the resulting reaction mixture was heated at 80° C. and stirred for 45 min at this temperature. According to LC-MS analysis, the reaction has then reached completion. The reaction mixture was cooled down to ambient temperature. The reaction mixture was poured onto 3.00 kg of ice. The resulting dark-brown suspension was stirred for 30 min and then filtrated. The filter cake was washed extensively with water and dried in vacuo at 55° C. The title product was obtained as a red-brown powder. LC/MS: 202 (M+H)+, 224 (M+H)+.

Workup

  1. additionThe addition
  2. additionAt the end of the addition
  3. customthe resulting reaction mixture
  4. temperaturewas heated at 80° C.
  5. temperatureThe reaction mixture was cooled down to ambient temperature
  6. stirringThe resulting dark-brown suspension was stirred for 30 min
  7. filtrationfiltrated
  8. washThe filter cake was washed extensively with water
  9. customdried in vacuo at 55° C

Sources & evidence

ORD record
ord-a1ae57585e40428791ea0d98487e6ecc
Source dataset
uspto-grants-2013_12
Patent number
US08598078B2

Reaction notes

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