Product main description: 5,6-Dihydroxyindole is a occurring compound found in various biological systems. It is a key intermediate in the melanin synthesis pathway, where it undergoes further chemical reactions to form the final pigment. It plays a role in determining the coloration of tissues and provides protection against the harmful effects of ultraviolet radiation. 5,6-Dihydroxyindole has been studied for its potential antioxidant properties, which may have implications for cellular protection and defense against oxidative stress. Technicial information: 1)Appearance : Off white to yellow Crystalline powder 2)Solubility :Soluble in water (slightly), and ethanol. 3)Melting Point :138° C 4)Boiling Point :411.2° C at 760 mmHg 5)Density :~1.5 g/cm3 (Predicted) 6)Refractive Index :n20D 1.80 (Predicted) 7)Structure:8) Product Manager Email: Joy@coreychem.com
Frequently Asked Questions (FAQ): 1）What are the key advantages of 5,6-Dihydroxyindole? --Non-toxic and biocompatible — As a naturally occurring endogenous substance, DHI has no toxic side effects, avoiding the carcinogenic, teratogenic, and allergenic risks associated with aniline-based hair dyes. --Excellent color retention — Hair colored with DHI does not easily fade with repeated washing and is resistant to sunlight degradation. --Effective hair penetration — Its small molecular weight allows deep penetration into the hair cortex, providing pronounced and long-lasting color results (10–15 days retention reported). --Regulatory approval — The EU Scientific Committee recommends a maximum concentration of 0.5% in oxidative hair dye products.
2)What are the known synthesis routes for 5,6-Dihydroxyindole? Route 1: Biomimetic synthesis from L-DOPA DHI can be synthesized starting from L-DOPA (L-3,4-dihydroxyphenylalanine), progressing through dopachrome formation followed by spontaneous decarboxylation and aromatization. Route 2: From 3,4-dimethoxyphenylacetonitrile (four-step process) This route involves: 1.Demethylation using HCl/pyridine as ether-cleavage reagent (yield: 90.2%) 2.Hydroxyl protection with benzyl chloride and potassium carbonate (yield: 87.8%) 3.Nitration with concentrated nitric acid (yield: 86.9%) 4.Reductive cyclization using 10% Pd-C catalyst with cyclohexene as hydrogen donor (yield: 85.2%) The overall yield from 3,4-dimethoxyphenylacetonitrile is approximately 58.6%.
3)How does DHI compare to p-phenylenediamine (PPD) as a hair dye precursor? DHI is increasingly viewed as a promising alternative to PPD in permanent hair dye formulations. The key distinction lies in DHI's bio-derived nature: it is a naturally occurring metabolite in the human body and can be converted into substances already present in biological systems, giving it an extremely high safety profile. PPD, by contrast, has been associated with allergic contact dermatitis and other sensitization concerns. DHI's ability to function as an oxidative dye precursor — compatible with isatin and other coupling agents — allows formulators to achieve permanent coloration through a more biologically compatible pathway.
4) What is DHI's role in melanin biosynthesis and why does it matter? In the melanogenesis pathway, L-tyrosine is enzymatically hydroxylated to L-DOPA, then oxidized to dopaquinone and cyclized to dopachrome. L-dopachrome can undergo spontaneous decarboxylation and rearrangement to form DHI. DHI then polymerizes to form eumelanin — the dark, photoprotective pigment found in skin, hair, and eyes. The ratio of DHI to its carboxylated counterpart DHICA in the medium directly influences the rate of melanin polymerization, making DHI concentration a critical regulatory factor in pigment formation. This significance extends to dermatological research, where DHI serves as an indispensable tool for studying pigmentation disorders such as vitiligo and melasma.
Application Cases: 1）What makes 5,6-Dihydroxyindole an indispensable tool for studying melanin biosynthesis and pigmentation disorders? 5,6-Dihydroxyindole is a critical intermediate in the eumelanin biosynthesis pathway, formed from the decarboxylation of dopachrome. It serves as the authentic monomeric precursor for synthesizing melanin-like pigments in vitro. Under the same reaction conditions where DOPA or dopachrome form black, insoluble melanin precipitates, DHI solutions also polymerize to form melanin, making it a valuable model compound for researchers. This role is essential for investigating pigment formation, skin biology, and pigmentation disorders such as vitiligo and melanoma. 2）How does DHI function in novel biomimetic hair colouring systems, and what are its advantages over traditional dyes? 5,6-Dihydroxyindole is explored as a precursor for a biomimetic hair colouring approach to dye grey hair. The mechanism involves the oxidative polymerization of DHI to form eumelanin-like pigments, which mimic natural hair colour. Its key advantage lies in its bio-derived nature and safety profile, offering an alternative to traditional hair dyeing agents that may cause scalp damage, induce melanocyte stem cell depletion, or trigger allergic reactions. The dyeability can be enhanced through pretreatment with specific cationic polymers that increase the adsorption and penetration of DHI into the hair fibre.
3) What antimicrobial and cytotoxic properties does DHI possess for pharmaceutical development? DHI exhibits broad-spectrum antibacterial, antifungal, antiviral, and antiparasitic activity. It has cytotoxic effects and is strongly toxic against various pathogens. Specifically, it is active against viruses and parasitic wasps, with reported LC50 values of 5.6 μM for lambda bacteriophage and 111.0 μM for eggs of the wasp Microplitis demolitor. These properties make it a subject of interest for pharmaceutical development, particularly in anti-infection research. 4)Why is 5,6-Dihydroxyindole considered suitable for biomaterials and drug delivery applications? DHI's biocompatibility makes it suitable for developing biomaterials for medical applications, such as drug delivery systems and tissue engineering scaffolds. A nanotechnological approach has demonstrated the encapsulation of DHI within breakable particles to trigger its oxidation into insoluble black melanin, which could be used for targeted colouring or therapeutic delivery. Additionally, DHI is investigated for therapeutic effects in neurodegenerative diseases due to its ability to influence neurotransmitter activity.
5) Can this product be utilized in the synthesis of conducting polymers and bioelectronic devices? DHI is used in the synthesis of conducting polymers, which have applications in electronics, sensors, and energy storage devices, offering advantages in conductivity and stability. Homogeneous, stable, electrically conducting DHI thin films have been fabricated, and their high biocompatibility makes them promising candidates for manufacturing biosensor devices.
Packaging: --For Laboratory / Research Scale: · Primary Container: Use a tightly sealed, amber glass vial to protect from light. · Atmosphere: The vial should be backfilled with an inert gas (argon or nitrogen) to displace oxygen and minimize oxidative degradation. --For Bulk / Industrial Scale: · Standard Packaging: Supplied in 1 kg, 5 kg, 10 kg, or 25 kg drums or fiber drums. · Custom Packaging: Many suppliers offer custom packaging upon request to meet specific handling or storage needs. Storage: · Temperature: The consensus for long-term stability is -20 °C. While some suppliers may suggest 2-8 °C, the compound is highly reactive and prone to degradation, making -20 °C a safer safeguard. · Atmosphere: Store under an inert gas (nitrogen or argon) . DHI is extremely sensitive to oxygen, which triggers spontaneous oxidative polymerization. · Light Protection: Keep in a dark place or use light-resistant containers, as light can accelerate decomposition. · Container: Ensure the container is kept tightly closed and stored in a cool, dry, and well-ventilated area away from incompatible materials (e.g., strong oxidizers).
Product Manager Information Product Manager: Joy Wu Email: Joy@coreychem.com
