反応 #485808

反応方程式

(3,4-dimethoxy-phenyl)-acetic acid

lithium diisopropylamide

iodomethylcyclopentane

→

3-cyclopentyl-2-(3,4-dimethoxy-phenyl)-propionic acid

収率 63.9%

溶媒

tetrahydrofuran 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone

1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone

反応条件

後処理

1. 1
   温度At this time, the reaction was cooled to 0° C.
2. 2
   workup.STIRRINGThe reaction mixture was stirred at 0° C. for 30 min
3. 3
   温度The reaction was then warmed to 25° C.
4. 4
   workup.STIRRINGwas stirred at 25° C. for 18 h
5. 5
   その他The reaction mixture was then quenched by the dropwise addition of saturated aqueous ammonium chloride solution (10 mL)
6. 6
   濃縮The resulting mixture was concentrated in vacuo
7. 7
   workup.ADDITIONThe residue was diluted with water (100 mL)
8. 8
   抽出This solution was extracted with ethyl acetate (3×50 mL)
9. 9
   洗浄The combined organic layers were washed with a saturated aqueous lithium chloride solution (1×100 mL)
10. 10
    乾燥dried over sodium sulfate
11. 11
    ろ過filtered
12. 12
    濃縮concentrated in vacuo

実験手順

A solution of freshly prepared lithium diisopropylamide (58.5 mL of a 0.91M stock solution, 53.2 mmol) cooled to −78° C. was treated with (3,4-dimethoxy-phenyl)-acetic acid (4.97 g, 25.3 mmol) in tetrahydrofuran/1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (25.3 mL, 3:1). The resulting solution was stirred at −78° C. for 45 min and at 25° C. for 15 min. At this time, the reaction was cooled to 0° C. and was treated with a solution of iodomethylcyclopentane (5.87 g, 27.8 mmol) in 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (1 mL). The reaction mixture was stirred at 0° C. for 30 min. The reaction was then warmed to 25° C. and was stirred at 25° C. for 18 h. The reaction mixture was then quenched by the dropwise addition of saturated aqueous ammonium chloride solution (10 mL). The resulting mixture was concentrated in vacuo. The residue was diluted with water (100 mL) and acidified to pH=1 with a 1N aqueous hydrochloric acid solution. This solution was extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with a saturated aqueous lithium chloride solution (1×100 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 70/30 hexanes/ethyl acetate) afforded 3-cyclopentyl-2-(3,4-dimethoxy-phenyl)-propionic acid (4.5 g, 63.8%) as a yellow solid: mp 111-112° C.; EI-HRMS m/e calcd for C16H22O4 (M+) 278.1518 found 278.1517.

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