[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[CH:4][C:3]=1[C:9]([F:12])([F:11])[F:10].[H-].[Na+].[Br:15][C:16]1[C:17](Cl)=[N:18][C:19]([CH3:25])=[C:20]([N+:22]([O-:24])=[O:23])[CH:21]=1>C[Si](C)(C)N[Si](C)(C)C.O1CCOCC1>[Br:15][C:16]1[C:17]([O:8][C:5]2[CH:6]=[CH:7][C:2]([Cl:1])=[C:3]([C:9]([F:10])([F:11])[F:12])[CH:4]=2)=[N:18][C:19]([CH3:25])=[C:20]([N+:22]([O-:24])=[O:23])[CH:21]=1
In a 50 mL single-necked round-bottomed flask, 0.13 ml of hexamethyldisilazane and 1.21 g of 4-chloro-3-trifluoromethyl-phenol are dissolved and stirred in 3.0 ml of dry dioxane under Argon atmosphere at ambient temperature. To this mixture, 270 mg of 55% sodium hydride suspension is added carefully (gas evolution) and stirring is continued for 30 minutes. After this, a solution of 1.55 g of 3-bromo-2-chloro-6-methyl-5-nitro-pyridine in 4.0 ml of dry dioxane is added dropwise by syringe and stirring is continued for 22 hours at ambient temperature. The reaction is then quenched by the addition of an excess of a dilute aqueous NaOH solution (pH=12 of water phase) and extraction carried out with cyclohexane. The organic phase is dried over sodium sulfate, filtered and concentrated in vacuo to obtain an orange oil. Purification by flash chromatography over a silica gel cartridge (50 g, 150 ml) using heptane/ethyl acetate 95:5 (v:v) as eluent gave 480 mg of the compound in the form of a wet solid.
Wird geladen…
