Reaktion #1250

Reaktionsgleichung

product

Ethyl 2,4-dioxo-3-oximino-4-(2,4,6-trimethylphenyl)butanoate

hydrochloric acid

methyl hydrazine

→

title compound

Ausbeute 78.9%

Ethyl 4-amino-1-methyl-5-(2,4,6-trimethylphenyl)pyrazole-3-carboxylate

Ausbeute 78.9%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenconcentrated
2. 2
   SonstigeThe resulting residue was partitioned between water and ethyl acetate
3. 3
   SonstigeThe organic phase was separated
4. 4
   Waschenwashed once with brine
5. 5
   workup.ADDITIONThe ethyl acetate solution was then mixed with 100 mL of water
6. 6
   workup.ADDITIONSolid Na2S2O4 in excess was added in small portion until TLC
7. 7
   SonstigeThe organic phase was separated
8. 8
   Waschenwashed with water and brine
9. 9
   Trocknendried over Na2SO4
10. 10
    SonstigeEvaporation

Vorschrift

To a solution of the product of step B (4.0 g, 13.8 mmol) and 1.6 mL of 12N hydrochloric acid in 100 mL of methanol was added dropwise 0.63 g of methyl hydrazine at 0° C. The reaction mixture was stirred at room temperature 4 hours, and then concentrated. The resulting residue was partitioned between water and ethyl acetate. The organic phase was separated and washed once with brine. The ethyl acetate solution was then mixed with 100 mL of water. Solid Na2S2O4 in excess was added in small portion until TLC showed completion of the reduction. The organic phase was separated, washed with water and brine, and dried over Na2SO4. Evaporation gave 3.1 g of the title compound as a foam.

Quelle