Reaktionsschritte
To a stirred solution of vanillin (3)(2 g, 13.16 mmol) and methyl 4-bromobutyrate (2.38 g, 13.16 mmol) in DMF (20 cm3) was added freshly ground anhydrous potassium carbonate (2.03 g, 14.47 mmol). The resulting pale pink suspension was heated at 100° C. for 90 mins, after which time the suspension has become milky pink in appearance. The mixture was then poured into water (50 cm3) and extracted with Et2O (3×30 cm3). The combined organic extracts were washed with water (2×30 cm3), then 1M HCl (2×30 cm3) before being dried (MgSO4) and concentrated in vacuo. The pale pink solid 4 was used without further purification (2.7 g, 82%). m.p. 69° C. [lit. (D. L. McMinn and M. M. Greenberg, Tetrahedron, 1996, 52, 3827) m.p. 68-69° C.]. Found C, 62.0; H, 6.3; C13H16O5 requires C, 62.0; H, 6.4%; Rf 0.44 (SiO2, hexane:EtOAc, 2:1 v/v); νmax (KBr disc)/cm−1 3100-2700 (m), 1740 (s), 1680 (s); δH (300 MHz, CDCl3) 2.19 (2H, q, J=6.6 Hz, CH2), 2.56 (2H, t, J=6.6 Hz, CH2), 3.68 (3H, s, OCH3), 3.91 (3H, s, OCH3), 4.15 (2H, t, J=6.6 Hz, CH2), 6.97 (1H, d, J=8.0 Hz, H-6′), 7.40 (1H, dd, J=8.0 Hz, J=1.8 Hz, H-5′), 7.44 (1H, d, J=1.8 Hz, H-3′), 9.84 (1H, s, CHO) ppm; δC (100 MHz, CDCl3) 24.1 (CH), 30.2 (CH2), 51.5 (OCH3), 55.8 (OCH3), 67.3 (CH), 109.2 (CH), 111.5 (CH), 126.6 (CH), 130.0, 149.7, 153.7, 173.3 (COOCH3), 190.8 (CHO) ppm; m/z (FAB) 253 [(MH+), 50%].
