5,6-Dihydroxyindoline

• CAS: 29539-03-5
• Catalog Number: ACM29539035
• Category: Main Products
• Molecular Weight: 232.07
• Molecular Formula: C8H10BrNO2
• Synonyms: Indoline-5,6-diol hydrobromide; 5,6-Dihydroxyindoline hydrobromide
• Appearance: White crystal powder

Case Study

5,6-Dihydroxyindoline: The Transient Intermediate That Powers Rapid Enzymatic Melanin-Mimetic Coatings

Li, Fan, et al. Enzyme and microbial technology 119 (2018): 58-64.

Polydopamine coatings, inspired by mussel adhesive proteins, typically form through slow spontaneous dopamine oxidation under alkaline conditions -- a 24-hour process unsuitable for pH-sensitive substrates. The key to acceleration lies in a fleeting intermediate: 5,6-dihydroxyindoline. When laccase catalyzes dopamine oxidation at mildly acidic pH, the catechol converts to dopamine-o-quinone, which undergoes intramolecular Michael addition as the side-chain amine attacks the quinone ring, yielding 5,6-dihydroxyindoline. This cyclized intermediate is further oxidized by laccase to 5,6-dihydroxyindoline quinone, driving polymerization at dramatically higher rates.
Experimental Protocol: Dopamine hydrochloride (2 mg/mL) was dissolved in sodium acetate buffer at pH 5.5 with 0.5 U/mL laccase at 30 degrees Celsius. Conventional polymerization used Tris-HCl buffer at pH 8.5 without enzyme. Films were deposited on silicon wafers and cotton fabrics. Structural analysis employed FT-IR, solid-state ¹³C CP-MAS NMR, and XPS. Surface morphology was examined by SEM and AFM. Coating stability was tested in 0.1 M HCl and 0.1 M NaOH for 12 hours.
Performance Evaluation: The laccase-catalyzed route achieved a UV-vis absorbance of 0.27 at 480 nm within 60 minutes, compared to only 0.08 for the conventional method. Optimal conditions were pH 5.5 with atmospheric oxygen. AFM revealed a 50 nm film after 1 hour of enzyme-catalyzed deposition, surpassing the 45 nm maximum achieved after 24 hours conventionally. Critically, the enzyme-produced film contained ether linkages between dopamine units confirmed by NMR signals at 72 ppm and FT-IR C-O-C stretching bands. This structural difference yielded markedly superior chemical stability in both strong acid and alkali. The film retained secondary reactivity toward amine-containing molecules, enabling hydrophobic surface modification with a water contact angle of 134 degrees that remained above 120 degrees after 25 washing cycles.

Custom Q&A

What is the molecular formula of 5,6-Dihydroxyindoline?

The molecular formula of 5,6-Dihydroxyindoline is C8H9NO2.

What is the molecular weight of 5,6-Dihydroxyindoline?

The molecular weight of 5,6-Dihydroxyindoline is 151.16 g/mol.

What are some synonyms for 5,6-Dihydroxyindoline?

Some synonyms for 5,6-Dihydroxyindoline include Indoline-5,6-diol and 5,6-Indolinediol.

What is the role of 5,6-Dihydroxyindoline?

5,6-Dihydroxyindoline has a role as a metabolite.

Is 5,6-Dihydroxyindoline a natural product? Where is it found?

Yes, 5,6-Dihydroxyindoline is a natural product found in Beta vulgaris and Daphnia pulex.

What is the InChIKey of 5,6-Dihydroxyindoline?

The InChIKey of 5,6-Dihydroxyindoline is VGSVNUGKHOVSPK-UHFFFAOYSA-N.

What is the Canonical SMILES representation of 5,6-Dihydroxyindoline?

The Canonical SMILES representation of 5,6-Dihydroxyindoline is C1CNC2=CC(=C(C=C21)O)O.

How many hydrogen bond donor counts does 5,6-Dihydroxyindoline have?

5,6-Dihydroxyindoline has 3 hydrogen bond donor counts.

What is the XLogP3-AA value of 5,6-Dihydroxyindoline?

The XLogP3-AA value of 5,6-Dihydroxyindoline is 1.2.

What is the topological polar surface area of 5,6-Dihydroxyindoline?

The topological polar surface area of 5,6-Dihydroxyindoline is 52.5 Ų.