WATER-SOLUBLE HETEROCYCLIC AZO COMPOUND AND ITS APPLICATION

摘要

NEW MATERIAL:A water-soluble heterocyclic azo compound of formulaI(R1 is thiazole ring, benzothiazole ring or halogen-substituted pyridine ring; R2 is carboxyl or OH; R3 is H, lower alkyl, lower sulfoalkyl or omega-sulfohydroxyalkyl; R4 is lower sufloalkyl or omega-sulfohydroxyalkyl; R5 is H or lower alkyl) and a salt thereof. EXAMPLE:Sodium 2-(3,5-dibromo-2-pyridylazo)-5-(N-ethyl-N-2-hydroxy-3-sulfopropylamino )benzoate. USE:Useful as a colorimetric reagent with a high sensitivity of minor metals, rich in water solubility, and practical and convenient without requiring organic solvents. PROCESS:A compound of formula II is reacted with a hologen-substituted 2- aminopyridinediazotate, etc. and coupled while blowing gaseous carbondioxide thereinto to afford the compound of formulaI.