Allyl bromide → Methyl 2-nicotinoyl-4-pentenoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Methyl 2-(nicotinoyl)acetate (17.9 g, prepared by the method of E Wenkert et al, J. Org. Chem., 1983, 48, 5006) was added under argon to a solution of sodium metal (2.3 g) in methanol (200 ml) and the resulting mixture was stirred at 25° C. for 30 mins. Allyl bromide (12.0 g) was then added and stirring was continued overnight. A further amount (about 2 g) of allyl bromide was added, the mixture was stirred for 48 hours, and then concentrated. The residual oil was partitioned between water and ether and the aqueous layer was extracted three times with ether. The combined extracts were washed with saturated brine, dried (MgSO4) and concentrated. The residue was purified by flash column chromatography, eluting with a mixture of petroleum ether (b.p. 60°-80°) and ethyl acetate (1:1, v/v) to give methyl-2-nicotinoyl-4-pentenoate (A) as a pale yellow oil (13.8 g); NMR 2.6-2.9 (2H,m), 3.7 (3H,s), 4.4 (1H,m), 4.9-5.2 (2H,m), 5.5-6.0 (1H,m), 7.2-7.5 (1H,m), 8.1-8.3 (1H,m), 8.7-8.8 (1H,m) and 9.1-9.2 (1H,m).

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