3-Pyridinecarboxaldehyde → 3-(Cyclopentylidenemethyl)pyridine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of cyclopentyltriphenylphosphonium bromide (226 g, 0.55 mol) in anhydrous tetrahydrofuran (1000 ml) at 2° C. was treated with vigorous stirring under an atmosphere of argon, with potassium t-butoxide (61.7 g, 0.55 mol). The dark red mixture was stirred at 5° C. for 80 minutes and then treated with pyridine-3-carbaldehyde (58.9 g, 0.55 mol) during a period of 20 minutes. The reaction mixture was stirred at 0° C. for 2 hours and then at 20° C. for 18 hours. The tetrahydrofuran was removed in vacuo (30° C.; 14 mmHg) and the residue extracted with pentane (2×500 ml) After treatment with decolourising charcoal (5 g), the mixture was filtered through a plug of flash silica gel (Merck 70-230 mesh; 13 cm×2 cm diameter). The filtrate was concentrated in vacuo (30° C., 14 mmHg; then 20° C., 0.01 mmHg) to afford 3-cyclopentylidenemethylpyridine (54 g, 0.34 mol) as an orange oil which was used without further purification;

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