Nitric Acid → 3-Hydroxy-4-methoxy-5-nitrobenzaldehyde

Temperature

27.5 °C

Isovanillin (500 gm) and acetic acid (1750 ml) were cooled to −5 to 0° C. To this solution, nitric acid (750 ml) was charged slowly at −5 to 0° C. with stirring. The temperature of the reaction mass was slowly raised to 25-30° C. and maintained for 12 hours. The reaction mass was quenched into ice water (4 kg), the solids filtered and washed with water (2 lt). The solids were stirred with a 1% sodium bicarbonate solution (1 lt), filtered and dried at 45-50° C. The solid was dissolved in 6 volumes of ethyl acetate, ethyl acetate was distilled off up to half the volume and 3 volumes of n-Hexane were charged slowly at 45-50° C. The reaction mass was cooled slowly to 0-5° C., maintained for 1 hour, the solids filtered, washed with 0.5 volumes of 1:1 mixture of ethyl acetate:n-Hexane and dried at 45-50° C. to yield the title compound (423 gm, 65% yield).

1. temperaturemaintained for 12 hours
2. customThe reaction mass was quenched into ice water (4 kg)
3. filtrationthe solids filtered
4. washwashed with water (2 lt)
5. stirringThe solids were stirred with a 1% sodium bicarbonate solution (1 lt)
6. filtrationfiltered
7. customdried at 45-50° C
8. dissolutionThe solid was dissolved in 6 volumes of ethyl acetate, ethyl acetate
9. distillationwas distilled off up to half the volume and 3 volumes of n-Hexane
10. additionwere charged slowly at 45-50° C
11. temperatureThe reaction mass was cooled slowly to 0-5° C.
12. temperaturemaintained for 1 hour
13. filtrationthe solids filtered
14. washwashed with 0.5 volumes of 1:1 mixture of ethyl acetate
15. dry with materialn-Hexane and dried at 45-50° C.

ORD record

ord-635bc2372f7546ab86acb9bbb2cbb56f

Source dataset

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08350029B2