Direct Red 81 free acid

7-benzamido-4-hydroxy-3-[[4-[(4-sulfophenyl)diazenyl]phenyl]diazenyl]naphthalene-2-sulfonic acid

CAS: 25188-42-5

Molecular Formula	`C29H21N5O8S2`
Molecular Weight	631.6 g/mol
LogP	4.7
Topological Polar Surface Area	224.0 A2
Hydrogen Bond Donors	4
Hydrogen Bond Acceptors	12
Rotatable Bonds	8
Exact Mass	631.0831
Heavy Atoms	44
Complexity	1250.0

Chemical Identifiers

CAS Number	25188-42-5
SMILES	`C1=CC=C(C=C1)C(=O)NC2=CC3=CC(=C(C(=C3C=C2)O)N=NC4=CC=C(C=C4)N=NC5=CC=C(C=C5)S(=O)(=O)O)S(=O)(=O)O`
InChIKey	`IGXZMQCLUNTWCC-UHFFFAOYSA-N`

📖 Product Overview

Direct Red 81 free acid (CAS: 25188-42-5) is a chemical compound with molecular formula C29H21N5O8S2 and molecular weight 631.6 g/mol. Its IUPAC systematic name is 7-benzamido-4-hydroxy-3-[[4-[(4-sulfophenyl)diazenyl]phenyl]diazenyl]naphthalene-2-sulfonic acid. LogP 4.7 Topological Polar Surface Area 224.0 A2 Hydrogen Bond Donors 4 Hydrogen Bond Acceptors 12 Rotatable Bonds 8 Exact Mass 631.0831 Heavy Atoms 44 Complexity 1250.0 InChI Key: IGXZMQCLUNTWCC-UHFFFAOYSA-N. SMILES: C1=CC=C(C=C1)C(=O)NC2=CC3=CC(=C(C(=C3C=C2)O)N=NC4=CC=C(C=C4)N=NC5=CC=C(C=C5)S(=O)(=O)O)S(=O)(=O)O.

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Safety Data Sheet (MSDS / SDS) View the Laboratory Chemical Safety Summary (LCSS) on PubChem — includes GHS classifications, hazard statements, first aid measures, and handling precautions.

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Frequently Asked Questions

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Lead time typically ranges from 3-7 business days for in-stock items. For larger quantities or custom orders, please contact us for specific lead times.

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Yes, we offer sample quantities for quality testing. Please submit an inquiry with your requirements and we will arrange samples accordingly.

What documentation do you provide with the product?

We provide COA (Certificate of Analysis), MSDS (Material Safety Data Sheet), and technical data sheets with each shipment.

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