Methyl formate → Methyl 2-(5-chloro-2-phenoxyphenyl)-3-hydroxyacrylate

Beteiligte Stoffe

Reaktionsschritte

A solution of (5-chloro-2-phenoxy-phenyl)-acetic acid methyl ester (167 g, 605 mmol) and methyl formate (173 mL, 2.8 mol) in t-butyl methyl ether (1 L) was cooled to −10° C. To this solution was added potassium t-butoxide (115 g, 1.03 mol) portionwise so that the temperature remained below 0° C. After 30 minutes, the reaction was quenched by addition of 4N aqueous hydrochloric acid (400 mL). The organic layer was separated and washed with water (3×350 mL) and saturated brine (350 mL). The organic fractions were combined and concentrated to dryness and used without purification. The product is 90% E as shown by NMR. 1H NMR (400 MHz, CDCl3) 3.6 (s, 3H, E methyl group; Z methyl is at 3.7), 6.8 (d, 1H), 6.9 (m, 2H), 7.0 (t, 1H), 7.2 (m, 3H), 7.3 (m, 2H), 11.8 (d, 1H, E hydroxy proton; Z hydroxy proton is at 4.7).

Herkunft & Nachweise