Reacción #10771

Ecuación de reacción

hydrochloric acid

4-Hydroxy-2-methoxy-5-thiophen-2-yl-benzaldehyde

4-acetylbenzoic acid

lithium methoxide

→

title compound

Rendimiento 5.0%

4-[3E-(4-Hydroxy-2-methoxy-5-thiophen-2-yl-phenyl)-acryloyl]-benzoic acid

Rendimiento 5.0%

Disolventes

dimethylformamide methanol

water

ethyl alcohol

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added
2. 2
   Extracciónextracted with ethyl acetate (4×25 mL)
3. 3
   SecadoThe combined organic extracts were dried over sodium sulfate
4. 4
   Otroevaporated to dryness
5. 5
   Otroto yield an orange solid
6. 6
   workup.ADDITIONcontaining residual amounts
7. 7
   Otroto remove acid impurity
8. 8
   Otrothe resulting precipitate was collected
9. 9
   Filtraciónon filter paper
10. 10
    Otrodried in vacuo

Procedimiento

4-Hydroxy-2-methoxy-5-thiophen-2-yl-benzaldehyde (Ex-47B, 0.30 g, 0.86 mmol) and 4-acetylbenzoic acid (0.13 g, 0.86 mmol) were dissolved in a dimethylformamide-methanol solution (6 mL, 7:3). After complete dissolution, lithium methoxide (0.12 g, 3.3 mmol) was added and the resulting red slurry was stirred in the dark at room temperature for 18 h. The mixture was diluted with water (15 mL), acidified with a 1 N hydrochloric acid solution, and extracted with ethyl acetate (4×25 mL). The combined organic extracts were dried over sodium sulfate and evaporated to dryness. The crude oil was subjected to silica gel chromatography (CH2Cl2:MeOH, 20:1) to yield an orange solid containing residual amounts of starting acid. The solid was taken up in ethyl alcohol (5 mL) to remove acid impurity and the resulting precipitate was collected on filter paper and dried in vacuo to yield 0.010 g (5%) of the title compound as an orange solid, mp 243° C. (dec). 1H-NMR (300 MHz, DMSO-d6) δ 8.18–8.23 (m, 3H), 8.06–8.09 (m, 2H), 8.02 (s, 1H), 7.85 (d, 1H, J=15.6 Hz), 7.68 (d, 1H, J=3.6 Hz), 7.47 (d, 1H, J=5.1 Hz), 7.11 (dd, 1H, J=5.1, 3.6 Hz), 6.67 (s, 1H), 4.13 (s, 1H), 3.89 (s, 3H). MS (ESI) m/z=381 ([M+H]30 , 100%). HRMS (ESI) Calcd. for C21H16O5S: 381.0796. Found: 381.0800.

Fuente