Réaction #1833211

Équation de réaction

2,6-dichloro-5-methoxy pyrimidine

vinyl magnesium bromide

2,3-dichloro-5,6-dicyano-p-benzoquinone

→

title compound

Rendement 60.0%

2,6-Dichloro-5-methoxy-4-vinyl pyrimidine

Rendement 60.0%

Solvants

tetrahydrofuran

tetrahydrofuran

Conditions de réaction

Traitement

1. 1
   AutreExcess Grignard reagent was quenched by addition of acetone (200 milliliters (mL)) while the temperature of the mixture
2. 2
   Températurewas maintained at a temperature below 20° C
3. 3
   workup.STIRRINGstirred overnight
4. 4
   AutreA yellow solid precipitated out
5. 5
   FiltrationThe solid was filtered
6. 6
   Lavagewashed with ethyl acetate (500 mL)
7. 7
   ConcentrationThe filtrate was concentrated under reduced pressure
8. 8
   workup.ADDITIONthe resulting crude compound was diluted with ethyl acetate (2 liters (L))
9. 9
   AutreThe resulting undissolved, dark, semi-solid was separated by filtration
10. 10
    ConcentrationIt was further concentrated under reduced pressure
11. 11
    Autreto provide a crude compound, which
12. 12
    Autrewas purified by column chromatography
13. 13
    LavageThe compound was eluted with 5% to 10% ethyl acetate in hexane mixture

Mode opératoire

To a solution of commercially available 2,6-dichloro-5-methoxy pyrimidine (100 grams (g), 0.55 moles (mol)) in dry tetrahydrofuran was added, dropwise, 1 molar (M) vinyl magnesium bromide in tetrahydrofuran solvent (124 g, 0.94 mol) over one hour (h) at room temperature. The mixture was then stirred for 4 h at room temperature. Excess Grignard reagent was quenched by addition of acetone (200 milliliters (mL)) while the temperature of the mixture was maintained at a temperature below 20° C. Thereafter, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ; 151 g, 0.67 mol) was added at once and stirred overnight. A yellow solid precipitated out. The solid was filtered and washed with ethyl acetate (500 mL). The filtrate was concentrated under reduced pressure and the resulting crude compound was diluted with ethyl acetate (2 liters (L)). The resulting undissolved, dark, semi-solid was separated by filtration using ethyl acetate. It was further concentrated under reduced pressure to provide a crude compound, which was purified by column chromatography. The compound was eluted with 5% to 10% ethyl acetate in hexane mixture to provide the title compound (70 g, 60%): mp 60-61° C.; 1H NMR (CDCl3) δ 3.99 (s, 3H), 5.85 (d, 1H), 6.75 (d, 1H), 6.95 (dd, 1H).

Source