Reaktion #77491

Reaktionsgleichung

water

N2

4-methyl-2H-isoquinolin-1-one

Na2S2O8

→

1-oxo-1,2-dihydro-isoquinoline-4-carbaldehyde

Lösungsmittel

DMSO

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONare added
2. 2
   TemperaturThen, whilst cooling
3. 3
   Temperaturthe mixture is cooled to 10° C.
4. 4
   workup.STIRRINGstirred for 10 min
5. 5
   Filtration1-oxo-1,2-dihydro-isoquinoline-4-carbaldehyde can be filtered from the light green suspension
6. 6
   Waschenwashed with water
7. 7
   ExtraktionThe filtrate is extracted 3 more times with EtOAc
8. 8
   WaschenThe EtOAc phases are washed with water (3×) and brine
9. 9
   Trocknendried (Na2SO4)
10. 10
    Einengenconcentrated by evaporation

Vorschrift

In an apparatus equipped with a mechanical stirrer (N2 gas), 135 g (848 mmol) of 4-methyl-2H-isoquinolin-1-one in 2.0 l of DMSO are heated to 50° C. After removing the oil bath, 108 g (447 mmol) of Cu(NO3)2.3H2O are added. Then, whilst cooling, 432 g (1.81 mol) of Na2S2O8 are added in portions, and finally 162 g (1.91 mol) of NaNO3. After stirring for 2 h at 50° C., the mixture is cooled to 10° C., mixed with 4 l of water and stirred for 10 min. 1-oxo-1,2-dihydro-isoquinoline-4-carbaldehyde can be filtered from the light green suspension and washed with water; m.p. 222-223° C. The filtrate is extracted 3 more times with EtOAc. The EtOAc phases are washed with water (3×) and brine, dried (Na2SO4) and concentrated by evaporation. Column chromatography of the residue (SiO2, methylene chloride/toluene/acetone 2:2:1) yields further 1-oxo-1,2-dihydro-isoquinoline-4-carbaldehyde.

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