Hydrazine hydrate (1:1) → (3-Amino-4-hydroxyphenyl)acetic acid

Temperature

60 °C

Compound III was synthesized according to the method of Zupancic and Trpin J. Prac. Chem. 33, 307-308 (1966); CA 66, 37580c. To a stirred solution of sodium hydroxide solution (1 g in 40 ml) in a round bottom flask was added 3-nitro-4-hydroxyphenylacetic acid (4.93 g, 0.025 mol). The solid dissolved at once giving an orange color solution. 10% Pd—C (50 mg) was added followed by dropwise addition of hydrazine monohydrate (3.25 ml). After the completion of the addition (5 minutes), the mixture was heated at 60° C. for 1.5 hr. The temperature was raise to reflux and heating continued for additional 0.5 hr. The solution appeared clear with Pd—C suspended in it. The solution was filtered hot, concentrated to half of the volume and then cooled. The solution was acidified carefully to pH 4-5 with acetic acid. The white precipitate separated after cooling was filtered off and washed with ethanol. m.p. 225-227° C. lit2. 229-230° C. (3.4 g, yield 30%). 1H NMR(D2O, δ) 7.9 (1H, d, j=7 Hz, 6-H); 7.8 (s, 1H, 2-H); 7.65 (1H, d, J=7 Hz, 5-H); 3.4 (2H, s, CH2COOH).

1. dissolutionThe solid dissolved
2. customat once giving an orange color solution
3. additionAfter the completion of the addition (5 minutes)
4. temperatureThe temperature was raise
5. temperatureto reflux
6. temperatureheating
7. filtrationThe solution was filtered hot
8. concentrationconcentrated to half of the volume
9. temperaturecooled
10. customThe white precipitate separated
11. temperatureafter cooling
12. filtrationwas filtered off
13. washwashed with ethanol
14. custom229-230° C. (3.4 g, yield 30%)

ORD record

ord-5b9972267c174a85a52eb88e79bb13a7

Source dataset

uspto-grants-2001_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06277984B1