3-Hydroxy PABA

3-Hydroxy PABA - Names and Identifiers

Name	4-Amino-3-hydroxybenzoic acid
Synonyms	3-Hydroxy PABA 3-hydroxy-4-AMino acid 3-HYDROXY-4-AMINOBENZOIC ACID 4-AMINO-3-HYDROXYBENZOIC ACID 4-Amino-3-hydroxybenzoic acid 3-Hydroxy-4-aminobenzoic acid BENZOIC ACID, 4-AMINO-3-HYDROXY-
CAS	2374-03-0
InChI	InChI=1/C7H7NO3/c8-5-2-1-4(7(10)11)3-6(5)9/h1-3,9H,8H2,(H,10,11)

3-Hydroxy PABA - Physico-chemical Properties

Molecular Formula	C7H7NO3
Molar Mass	153.14
Density	1.028
Melting Point	211-215 °C (lit.)
Boling Point	385.7±37.0 °C(Predicted)
Flash Point	187.067°C
Water Solubility	Soluble in chloroform, and aqeous ethanol, water (Partly miscible)
Solubility	DMSO (Slightly), Methanol (Slightly)
Vapor Presure	0mmHg at 25°C
Appearance	tawny solid
Color	Yellow-brown to brown
BRN	509859
pKa	4.74±0.10(Predicted)
Storage Condition	Keep in dark place,Sealed in dry,Room Temperature
Refractive Index	1.691
MDL	MFCD00017094
Physical and Chemical Properties	Density 1.028 melting point 21-215°C

3-Hydroxy PABA - Risk and Safety

Risk Codes	R36/37/38 - Irritating to eyes, respiratory system and skin. R22 - Harmful if swallowed
Safety Description	S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S37/39 - Wear suitable gloves and eye/face protection
WGK Germany	3
HS Code	29225090
Hazard Note	Irritant

3-Hydroxy PABA - Reference Information

Application

4-amino-3-hydroxybenzoic acid is a pharmaceutical intermediate, which can be nitrated from 3-hydroxybenzoic acid to obtain 3-hydroxy-4-nitrobenzoic acid, and then reduce the nitro to obtain 4-amino-3-hydroxybenzoic acid. 4-Amino-3-hydroxybenzoic acid can be used to prepare 4-(3,5 dichloro-2-hydroxybenzylamine)-3-hydroxybenzoic acid with neuroprotective effect.

preparation

step 1, preparation of 3-hydroxy-4-nitrobenzoic acid (compound 4A) 3-hydroxybenzoic acid (220mg,1.6mmol) is dissolved in acetonitrile, completely dissolved, slowly added with cerium ammonium nitrate (1.26g,2.3mmol) in batches, and stirred overnight at room temperature. At the end of the reaction, water was added to quench the reaction, ethyl acetate was extracted, organic terms were combined, dried, and concentrated under reduced pressure. After column chromatography (ethyl acetate elution), solid product compound 4A(85mg,27% yield) was obtained. Step 2, Preparation of 4-Amino -3-Hydroxybenzoic Acid (Compound 4B) Compound 4A(85mg,0.8mmol) is dissolved in methanol, Pd/C catalyst is added and reacted at room temperature under hydrogen protection overnight, the reaction is finished, the solid insoluble matter is filtered and removed, and the solid obtained after the organic layer is concentrated under reduced pressure is directly used for the next reaction without further purification.

Last Update：2024-04-09 21:01:54