Réaction #72408

Équation de réaction

ethyl 7-cyclopropylheptanoate

ammonium chloride

cyclopropylmagnesium bromide

NaOH

ethyl 7-iodoheptanoate

→

7-cyclopropylheptanoic acid

Rendement 40.0%

Solvants

water

THF

THF

THF

Conditions de réaction

Traitement

1. 1
   Autreequipped with a Teflon-coated magnetic stirring bar
2. 2
   AutreThe flask was evacuated
3. 3
   Températurewhile being heated
4. 4
   Autrepurged with argon from the balloon
5. 5
   workup.ADDITIONbefore addition of any reagents or solvents
6. 6
   workup.ADDITIONAfter the addition
7. 7
   workup.ADDITIONAfter the addition
8. 8
   workup.STIRRINGstirred for 2 h
9. 9
   Températureto warm to ambient temperature
10. 10
    workup.STIRRINGstirred overnight
11. 11
    ExtractionThe organic product was extracted into an ether layer which
12. 12
    Lavagewas washed with brine
13. 13
    Séchagedried over magnesium sulfate
14. 14
    Filtrationfiltered
15. 15
    Concentrationconcentrated in vacuo
16. 16
    Autreto yield a residue
17. 17
    workup.STIRRINGThe mixture was stirred at ambient temperature overnight
18. 18
    LavageThe alkaline solution was washed with ether
19. 19
    AutreThe aqueous layer was separated
20. 20
    Autresubjected to in vacuo evaporation
21. 21
    Autreto remove any residual ether
22. 22
    Autreleading to the precipitation of a white solid
23. 23
    workup.STIRRINGStirring
24. 24
    workup.WAITwas continued for an additional 30 minutes
25. 25
    Filtrationthe precipitate was filtered off with suction through a sintered glass funnel
26. 26
    LavageThe collected solid was successively washed with water and two-50-ml of hexane
27. 27
    Autrewas dried in vacuo at room temperature for 2 days

Mode opératoire

All reactions reported in this example were carried out in an oven-dried three-necked, round-bottomed flasks equipped with a Teflon-coated magnetic stirring bar, copper iodide and a T-joint to which an argon-filled balloon had been attached. The flask was evacuated while being heated, then purged with argon from the balloon. This operation was repeated three times before addition of any reagents or solvents. To a stirred suspension of cuprous iodide (2.38 g, 12.5 mmol) in 30 mL of dried THF at ca −78° C. under argon, cyclopropylmagnesium bromide in THF solution (0.5M, 50 ml, 25 mmol) was added via syringe. After the addition had been completed, the mixture was stirred for 30 min and a solution of ethyl 7-iodoheptanoate (3.02 g, 10.63 mmol) in 10 ml of THF was added. After the addition, the reaction was allowed to warm to 0° C. and stirred for 2 h. It was allowed to warm to ambient temperature and stirred overnight. The reaction was poured into a saturated ammonium chloride solution. The organic product was extracted into an ether layer which was washed with brine, dried over magnesium sulfate, filtered, and concentrated in vacuo to yield a residue. 1H NMR confirmed the desired ethyl 7-cyclopropylheptanoate. GC indicated a single peak material. To the residue were added 25 mL of water and a 25 ml of a solution of NaOH (2N). The mixture was stirred at ambient temperature overnight. The alkaline solution was washed with ether. The aqueous layer was separated and subjected to in vacuo evaporation to remove any residual ether. The alkaline solution was acidified with an aqueous solution of HCl (2N) leading to the precipitation of a white solid. Stirring was continued for an additional 30 minutes and then the precipitate was filtered off with suction through a sintered glass funnel. The collected solid was successively washed with water and two-50-ml of hexane, and was dried in vacuo at room temperature for 2 days to afford 0.72 g (40%) of 7-cyclopropylheptanoic acid as a white solid. 1H NMR (400 MHz DMSO-d6) δ: 0 (m, 2H), 0.37 (m, 2H), 0.66 (m, 1H), 1.16-1.18(m, 2H), 1.34-1.50 (m, 6H), 1.78 (m, 2H), 2.20 (m, 2H), 12.0 (s, 1H). 13C NMR (100 MHz DMSO-d6) δ: 4.27, 10.65, 24.50, 28.61, 29.05, 33.64, 34.01, 174.43. Anal. Calcd for C10H18O2: C, 70.22; H, 10.66. Found: C, 70.05, H, 10.34 with a Karl Fisher water content %: 0.46.

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