3-Nitrobenzaldehyde → 5(4H)-Oxazolone, 2-methyl-4-[(3-nitrophenyl)methylene]-

Temperature

120 °C

3-Nitrobenzaldehyde (45.3 g, 0.3 mol), N-acetylglycine (42.1 g, 0.36 mol) and sodium acetate (32 g, 0.39 mol) were mixed with acetic anhydride (142 ml, 1.5 mol) and the resulting mixture heated with stirring to 120° C. for 6 hrs, giving a dark solution. The mixture was then cooled to RT overnight, resulting in the formation of a precipitated solid. The reaction mixture was poured into ice-water (130 g) and the resulting suspended solid was collected by filtration. The crude solid product (72 g) was washed with acetone (80 ml) then recrystallized from hot acetone (320 ml) to give a crystalline solid that was washed with 50% aqueous ethanol, then dried at 40° C./40 mmHg to give 2-methyl-4-(3-nitrobenzylidene)oxazol-5(4H)-one (49.0 g, 78%) as pale yellow needles. 1H NMR (δ, 250 MHz, CDCl3)=2.47 (3H, s), 7.15 (1H, s), 7.63 (1H, dd, 8.2 & 7.6 Hz), 8.27 (1H, d, 8.2 Hz), 8.34 (1H, d, 7.6 Hz), 9.02 (1H, s).

1. temperaturethe resulting mixture heated
2. customgiving a dark solution
3. temperatureThe mixture was then cooled to RT overnight
4. customresulting in the formation of a precipitated solid
5. filtrationwas collected by filtration
6. washThe crude solid product (72 g) was washed with acetone (80 ml)
7. customthen recrystallized from hot acetone (320 ml)
8. customto give a crystalline solid
9. washthat was washed with 50% aqueous ethanol
10. customdried at 40° C./40 mmHg

ORD record

ord-42830f516b7f4c5ea03767d25b215e3e

Source dataset

uspto-grants-2014_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08710100B2