2,3-Benzofurandione, 2-[O-(2-hydroxyethyl)oxime] 3-(O-methyloxime) → (E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyloxime

HRID 1858136Notes

Reaction equation

HRID 1858136 reaction equation
[CH3:1][O:2][N:3]=[C:4]1[C:8]2[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=2[O:6][C:5]1=[N:13][O:14][CH2:15][CH2:16][OH:17]>C(OCC)C.Cl>[CH3:1][O:2]/[N:3]=[C:4](\[C:5]1[O:17][CH2:16][CH2:15][O:14][N:13]=1)/[C:8]1[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=1[OH:6]

Participants

4

Reactant 1

HCID 543010792,3-Benzofurandione, 2-[O-(2-hydroxyethyl)oxime] 3-(O-methyloxime)

Product 1

HCID 135512723(E)-(5,6-dihydro-1,4,2-dioxazin-3-yl)(2-hydroxyphenyl)methanone O-methyloximeYield 70.7%

Reagents, catalysts & solvents 2

HCID 313Hydrochloric AcidSolventHCID 3283Diethyl EtherSolvent

Procedure

2 g of benzofuran-2,3-dione 2-[O-(2-hydroxy-ethyl)-oxime] 3-(O-methyl-oxime) (II-1) (content according to HPLC analysis 96.88%, 0.0082 mol) prepared by the method of process e) are dissolved in 50 ml of diethyl ether saturated beforehand with hydrogen chloride gas at 0° C. Without further cooling, the mixture is stirred for 30 minutes, the solvent is then distilled off under reduced pressure and the residue is taken up once more in diethyl ether. Some of the product crystallizes out and is filtered off. The mother liquor is concentrated under reduced pressure and the residue is dissolved in 25 ml of diethyl ether saturated with hydrogen chloride gas at 0° C. Without further cooling, the solution is stirred for a further 30 minutes, the solvent is distilled off under reduced pressure and the residue is once more taken up in diethyl ether. A further fraction of the product crystallizes out and is likewise filtered off. In total, 1.37 g (69% of theory) of (5,6-dihydro-1,4,2-dioxazin-3-yl)-(2-hydroxy-phenyl)-methanone O-methyl-oxime (1) are obtained (content according to HPLC analysis: 97.59%).

Workup

  1. distillationthe solvent is then distilled off under reduced pressure
  2. customSome of the product crystallizes out
  3. filtrationis filtered off
  4. concentrationThe mother liquor is concentrated under reduced pressure
  5. dissolutionthe residue is dissolved in 25 ml of diethyl ether saturated with hydrogen chloride gas at 0° C
  6. stirringWithout further cooling, the solution is stirred for a further 30 minutes
  7. distillationthe solvent is distilled off under reduced pressure
  8. customA further fraction of the product crystallizes out
  9. filtrationis likewise filtered off

Sources & evidence

ORD record
ord-5f8098697c98461d955cfe3af18322e8
Source dataset
uspto-grants-2000_11
Patent number
US06150521

Reaction notes

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