摘要 |
Azo dyestuff ester of the formula A-N=N-B(OR)n wherein A is a five- or six-membered heterocyclic radical of up to 2 hetero ring atoms selected from nitrogen, sulfur and oxygen, and wherein the heterocyclic ring may be substituted with at least one member of the group selected from halogen, lower alkyl and lower alkoxy; or A is phenyl substituted by at least one member of the group selected from lower alkyl, lower alkoxy, nitro, sulphanato and acylamino; B is benzene, naphthalene or quinoline, optionally substituted with one or two radicals selected from sulphanato, lower alkoxy and lower alkoxypoly-alkyleneoxy; R is a carboxylic acid residue or an amino acid or peptide residue having a nitrogen protective group; and n is 1 or 2. This dyestuff is particularly useful as a chromogen in a diagnostic composition for detecting leukocytes in body fluids.
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