Réaction #62264

Équation de réaction

Water

vanillin

methyl-4-bromobutyrate

potassium carbonate

→

keto-ester

Rendement 66.0%

4-(4-formyl-2-methoxyphenoxy)-butyric acid methyl ester

Rendement 66.0%

Solvants

DMF

Conditions de réaction

Traitement

1. 1
   Autrecrystallised
2. 2
   FiltrationThe resulting mixture was filtered
3. 3
   Autredried in vacuo for 16 hours

Mode opératoire

A solution of vanillin (47)(40.00 g, 262.89 mmol) and methyl-4-bromobutyrate (50.00 g, 276.18 mmol) in DMF (200 mL) was allowed to stir over potassium carbonate (51.53 g, 372.40 mmol) for 16 hours. Water was added to the reaction mixture at which time the product crystallised. The resulting mixture was filtered and dried in vacuo for 16 hours to afford the keto-ester (48) as a white solid (41.3 g, 66%). MP=57-59° C. 1H NMR (250 MHz, CDCl3) δ 9.80 (s, 1H), 7.46-7.40 (m, 2H), 6.97 (d, J=8.1 Hz, 1H), 4.16 (t, J=6.3 Hz, 2H), 3.92 (s, 3H), 3.70 (s, 3H), 2.57 (t, J=7.2 Hz, 2H), 2.20 (pent, J=6.7 Hz, 2H). 13C NMR (67.8 MHz, CDCl3) 188.2 (Cl), 173.7 (C12), 153.8 (Cquat.), 152.0 (Cquat.), 144.1 (Cquat.), 125.8 (Cmethine), 110.3 (C3), 108.5 (C6), 69.0 (C9), 57.0 (C8), 52.2 (C13), 30.6 (C11), 24.5 (C10). It was decided to adopt the numbering system shown in the figure below for the molecule for ease of peak assignment in 13C NMR.

Source