Реакция #1833211

Уравнение реакции

2,6-dichloro-5-methoxy pyrimidine

vinyl magnesium bromide

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

→

title compound

Выход 60.0%

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

Выход 60.0%

Растворители

tetrahydrofuran

tetrahydrofuran

Условия реакции

Обработка

1. 1
   ДругоеExcess Grignard reagent was quenched by addition of acetone (200 milliliters (mL)) while the temperature of the mixture
2. 2
   Температураwas maintained at a temperature below 20° C
3. 3
   workup.STIRRINGstirred overnight
4. 4
   ДругоеA yellow solid precipitated out
5. 5
   ФильтрацияThe solid was filtered
6. 6
   Промывкаwashed with ethyl acetate (500 mL)
7. 7
   КонцентрированиеThe filtrate was concentrated under reduced pressure
8. 8
   workup.ADDITIONthe resulting crude compound was diluted with ethyl acetate (2 liters (L))
9. 9
   ДругоеThe resulting undissolved, dark, semi-solid was separated by filtration
10. 10
    КонцентрированиеIt was further concentrated under reduced pressure
11. 11
    Другоеto provide a crude compound, which
12. 12
    Другоеwas purified by column chromatography
13. 13
    ПромывкаThe compound was eluted with 5% to 10% ethyl acetate in hexane mixture

Методика

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).

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