2-AMINOTHIAZOLE-5-CARBOXYLIC ACID

China [CN]

I. Basic Information

Chinese Name: 2-Aminothiazole-5-carboxylic acid

English Name: 2-Aminothiazole-5-carboxylic acid

CAS Number: 4028-49-5

Molecular Formula: C₄H₄N₂O₂S

Molecular Weight: 144.15 (Calculated: C: 33.32%, H: 2.80%, N: 19.43%, O: 22.20%, S: 22.25%)

II. Physical and Chemical Properties

Appearance: Typically a white to pale yellow crystalline powder.

Melting Point: Approximately 245-248°C (decomposes, slightly different in different literature reports).

Solubility: Slightly soluble in water, soluble in hot water, ethanol, and other organic solvents, and readily soluble in alkaline solutions (such as sodium hydroxide solution). This is due to the amphoteric nature of the carboxyl (-COOH) and amino (-NH₂) groups within the molecule. pKa: The pKa of carboxyl group is about 2.5-3.0, and the pKa of conjugate acid of amino group is about 8.0-8.5, which has zwitterionic properties.