Réaction #329316

Équation de réaction

Na2SO3

phthalic anhydride

phthalic anhydride

Na2SO3

Na2CO3

urea hydrogen peroxide

tert-Butyl-3-(3-methylpyridin-2-yl)benzoate

→

2-(3-(tert-butoxycarbonyl)phenyl)-3-methylpyridine-1-oxide

Rendement 95.0%

Solvants

Water

EtOAc

Conditions de réaction

Traitement

1. 1
   Températureto maintain the temperature in the reactor below 45° C
2. 2
   workup.STIRRINGthe mixture is stirred for an additional 30 minutes
3. 3
   Autrethe layers separated
4. 4
   workup.STIRRINGThe organic layer is stirred
5. 5
   workup.STIRRINGAfter stirring for 30 minutes
6. 6
   Autreto separate
7. 7
   LavageThe organic phase is washed 13%
8. 8
   FiltrationThe organic phase is then filtered
9. 9
   Concentrationconcentrated

Mode opératoire

tert-Butyl-3-(3-methylpyridin-2-yl)benzoate (1.0 eq) is dissolved in EtOAc (6 vol). Water (0.3 vol) is added followed by urea-hydrogen peroxide (3 eq). The phthalic anhydride (3 eq) is added portion-wise as a solid to maintain the temperature in the reactor below 45° C. After completion of phthalic anhydride addition, the mixture is heated to 45° C. After stirring for an additional 4 hours, the heat is turned off. 10% w/w aqueous Na2SO3 (1.5 eq) is added via addition funnel. After completion of Na2SO3 addition, the mixture is stirred for an additional 30 minutes and the layers separated. The organic layer is stirred and 10% w/w aq. Na2CO3 (2 eq) is added. After stirring for 30 minutes, the layers are allowed to separate. The organic phase is washed 13% w/v aq NaCl. The organic phase is then filtered and concentrated to afford crude 2-(3-(tert-butoxycarbonyl)phenyl)-3-methylpyridine-1-oxide (95%) that is used directly in the next step.

Source