Tetrahydrofuran → 6-Cyclopentyl-5-methyl-nicotinic acid isopropyl ester
Reaktionsgleichung
[CH:1]([O:4][C:5](=[O:14])[C:6]1[CH:11]=[C:10]([CH3:12])[C:9](Cl)=[N:8][CH:7]=1)([CH3:3])[CH3:2].[CH2:15]1[CH2:19]O[CH2:17][CH2:16]1.O1CCOC[CH2:21]1>>[CH:1]([O:4][C:5](=[O:14])[C:6]1[CH:11]=[C:10]([CH3:12])[C:9]([CH:15]2[CH2:19][CH2:21][CH2:17][CH2:16]2)=[N:8][CH:7]=1)([CH3:3])[CH3:2]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 75 °C
Versuchsvorschrift
Under argon, Pd(dppf) (11 mg, 14 μmol) is added to a solution of 6-chloro-5-methyl-nicotinic acid isopropyl ester (300 mg, 1.40 mmol) in dioxane (60 mL). To this mixture, a 0.5 M solution of cyclopentyl zink chloride in THF (452 mg, 2.11 mmol, 4.2 mL) is added dropwise. The mixture is stirred at 75° C. for 18 h before it is cooled to rt and quenched with water. The mixture is further diluted with water and extracted twice with EA (100 mL). The combined org. extracts are dried over MgSO4, filtered and concentrated. The crude product is purified on prep. TLC plates with heptane:EA 1:1 to give 6-cyclopentyl-5-methyl-nicotinic acid isopropyl ester (138 mg) as a pale yellow oil; LC-MS: tR=0.91 min; [M+1]+=248.53.