反应详情

Condensation with Meldrum's acid was carried out according to the method of Bigi et. al. (2001) Tetrahedron Lett. 42:5203-5205. A 2 L pear-shaped flask was charged with 4-hydroxybenzaldehyde (50 g, 409 mmol) and water (400 mL). The flask was placed in a water bath at 75° C., and Meldrum's acid (62 g, 430 mmol) was added as a slurry in 400 mL of water. The reaction mixture was agitated for 2 hours and cooled in an ice bath for 2 hours. The product was collected by filtration and rinsed with cold water. After drying thoroughly, adduct M1.1 was obtained as a fine yellow powder. MS ESI (pos.) m/e: 519.0 (2M+Na). 1H NMR (500 MHz) (DMSO-d6) δ 9.75 (br s, 1H); 8.27 (s, 1H); 8.24 (d, 2H, J=10 Hz); 6.98 (d, 2H, J=10 Hz);.1.76 (s, 6H).

1. customThe flask was placed in a water bath at 75° C.
2. temperaturecooled in an ice bath for 2 hours
3. filtrationThe product was collected by filtration
4. washrinsed with cold water
5. customAfter drying thoroughly
6. customadduct M1.1 was obtained as a fine yellow powder