Hydrochloric Acid → 3-(3,4,5-Trimethoxyphenyl)acrylic acid

Participants

Reaction Steps

A mixture of 3,4,5-trimethoxybenzaldehyde (5.0 g, 0.025 mol), malonic acid (5.30 g, 0.050 mol), piperidine (4–8 mL) and acetic acid (25–35 mL) were taken in a 100 ml Erlenmeyer flask fitted with a loose funnel at the top. The flask was shaken well and placed inside a microwave oven and irradiated for 4–8 minutes in parts. The cooled mixture was poured into ice cold water and then acidified with 5% HCl. The precipitated yellow solid was filtered and recrystallized with aq. ethanol to afford 3,4,5-trimethoxycinnamic acid in 88% yield; mp 127° C. (lit mp 126–128° C.) whose spectral data was found similar to the reported values 1H NMR (CDCl3) δ 7.73 (1H, d, J=16.0 Hz, —CH═CH—COOH), 6.78 (2H, s, H-2 & H-6), 6.38 (1H, d, J=16.0 Hz, CH═CH—COOH), 3.91 (9H, s, 3-OCH3, 4-OCH3 & 5-OCH3); 13C NMR: δ 172.6 (COOH), 153.8 (C-3 and C-5), 147.4 (C-4), 140.8 (CH═CH—COOH), 129.8 (C-1), 116.8 (CH═CH—COOH), 105.8 (C-2 and C-6), 61.4 (4-OCH3), 56.5 (3-OCH3 and 5-OCH3).

Provenance & Evidence