M-Cresol → t-butyl (1S)-2-(benzyloxy)-1-[(3-methylphenoxy)methyl]ethylcarbamate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To t-butyl (1R)-2-(benzyloxy)-1-(hydroxymethyl)ethylcarbamate (3.23 g) obtained in Step 1 were added dichloromethane (40 ml), methanesulfonyl chloride (1.07 ml) and triethylamine (3.20 ml), and the mixture was stirred at 0° C. for 3 hrs. The reaction mixture was diluted with dichloromethane and, after washing with water, the organic layer was dried over anhydrous sodium sulfate. The solvent was evaporated to give a crude product. To this crude product were added dimethylformamide (30 ml) and lithium chloride (2.4 g), and the mixture was stirred overnight at 40° C. The solvent was evaporated, and the residue was diluted with ethyl acetate and washed with water. The organic layer was dried over anhydrous sodium sulfate, and the solvent was evaporated to give a crude product. To this crude product were added dimethylformamide (20 ml), potassium carbonate (2.4 g) and m-cresol (1.47 ml), and the mixture was stirred overnight at 90° C. The mixture was diluted with ethyl acetate and, after washing with water, the organic layer was dried over anhydrous sodium sulfate. The solvent was evaporated and the obtained crude product was purified by silica gel chromatography (ethyl acetate-hexane) to give t-butyl (1S)-2-(benzyloxy)-1-[(3-methylphenoxy)methyl]ethylcarbamate (1.5 g).

Herkunft & Nachweise