Toluene → 1163-13-9

Participants

Reaction Steps

To dry toluene (40) are added 4-methoxy-3-methyl-1-naphthol (1.88 g) and potassium hydride (401 mg) followed by refluxing in nitrogen streams for an hour. After spontaneous cooling, geranyl bromide (1.95 g) is added and the mixture is stirred at room temperature for 24 hours. To the reaction mixture is added petroleum ether (100 ml) and the precipitated potassium bromide is filtered off and the solvent is distilled off at room temperature and under reduced pressure. The residue is dissolved in dimethylformamide (50 ml) followed by addition of bis(salicylidene)ethylenediiminocobalt(II) (100 mg). The mixture is stirred in oxygen gas streams at atmospheric temperature and pressure for one hour, after which the product is extracted with ether. The ethereal layer is washed with water and dried over anhydrous sodium sulfate, followed by distillation removal of the solvent. The residue is fractionally purified by silica gel column chromatography (developing solvent:ether-petroleum ether=1:19). The crude crystals thus obtained are recrystallized from acetone-alcohol. The above procedure yields menaquinone-2 (1.45 g) as yellow needles melting at 51° C.-53° C.

Provenance & Evidence