Sulfuric Acid → 8-methyl-6-nitro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

HRID 1983070Notes

Reaction equation

HRID 1983070 reaction equation
[N+:1]([O-:4])([O-])=[O:2].[K+].[CH3:6][C:7]1[CH:18]=[CH:17][CH:16]=[C:9]2[C:10]([O:12][C:13](=[O:15])[NH:14][C:8]=12)=[O:11].S(=O)(=O)(O)O>>[CH3:6][C:7]1[CH:18]=[C:17]([N+:1]([O-:4])=[O:2])[CH:16]=[C:9]2[C:10]([O:12][C:13](=[O:15])[NH:14][C:8]=12)=[O:11]

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 24434Potassium NitrateHCID 27598708-methyl-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Product 1

HCID 218865708-methyl-6-nitro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Conditions

Temperature
25 °C

Procedure

Potassium nitrate (1.43 g, 14.1 mmole) was added in small portions at <30° C. with external water-bath cooling to a solution of 3-methyl isatoic anhydride (2.50 g, 14.1 mmole) and concentrated sulfuric acid (8 mL). The resulting mixture was stirred at 25° C. for 1.5 hours and then was poured into approximately 200 g of ice with stirring. After the ice had melted, the solid product was isolated by filtration and washed with dilute aqueous HCl and then air-dried. The product was suspended in acetonitrile (50 mL) and concentrated in vacuo to give 2.75 of a yellow solid. 1H NMR (DMSO-d6): δ 11.6 (br s, 1H), 8.45 (d, 1H), 8.42 (d, 1H), 2.43 (s, 3H).

Workup

  1. stirringwith stirring
  2. customthe solid product was isolated by filtration
  3. washwashed with dilute aqueous HCl
  4. customair-dried
  5. concentrationconcentrated in vacuo
  6. customto give 2.75 of a yellow solid

Sources & evidence

ORD record
ord-e6aa54005ece4b1b8a31b4bc31f391b8
Source dataset
uspto-grants-2009_06
Patent number
US07541377B2

Reaction notes

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