5-Bromoindole carries a presence in many chemistry research labs and even pockets of the industry. Its chemical formula reads as C8H6BrN, with the structure showing the classic indole ring—a hexagonal benzene ring fused to a five-membered pyrrole ring. What sets it apart is a single bromine atom attached to the fifth carbon of the indole core, a switch that changes its physical and chemical behavior in more ways than one. Many researchers run into this compound while working with pharmaceuticals or while synthesizing new organic molecules. CAS number given for reference: 10075-50-0.
5-Bromoindole emerges most often as an off-white to slightly pale brown solid, arriving from suppliers in the form of fine powder, crystalline flakes, or small clumped pearls depending on source and handling. In a handful of cases, you might spot it pressed into larger granules, but powder remains prevalent. No liquid or solution version exists unless someone has freshly dissolved the raw material in a compatible solvent, like dichloromethane or ethanol, for a specific process or reaction. Under most storage conditions, this substance does not appear glossy or moist, and it will keep its integrity inside standard amber glass bottles if moisture and air stay minimal.
By weight, the molecule clocks in at a molar mass of 196.05 g/mol. The bromine adds significant heft and brings specific reactivity. The measured density hovers around 1.6 grams per cubic centimeter, making it denser than water but not so tough to handle. It doesn’t melt until its temperature goes above 70°C, and it resists boiling, as you might guess from the aromatic systems, until it starts to decompose at high temperature.
In terms of solubility, 5-Bromoindole dissolves moderately well in acetone, DMSO, and chloroform, and only sparingly in water. Its reactivity hinges largely on the bromine position, making it a flexible intermediate for Suzuki and Buchwald-Hartwig couplings, strong enough for medicinal chemistry and novel material synthesis. Once the indole skeleton gains the bromo modification, substitution and further functionalization become straightforward, which explains its steady demand as a starting material.
Working with 5-Bromoindole warrants diligence and awareness. The material isn’t classed as extraordinarily hazardous, and its acute toxicity, based on available studies, remains fairly low. Still, accidental contact with skin, eyes, or respiratory tract may cause localized irritation, so gloves, goggles, and working in a well-ventilated fume hood remain non-negotiable. It does not emit foul odors or fumes under ambient conditions, but spills or dusting during powder transfer may provoke coughing and sneezing. It stores best in an airtight vessel, away from light and humidity, and regular inventory checks keep accidents at bay. According to global chemical regulations, its transport falls under the HS Code 2933.99, tailored for heterocyclic compounds with nitrogen.
Demand for 5-Bromoindole in the specialty chemical industry often links back to its function as a building block. In pharmaceutical discovery, teams use it to build up molecules with indole motifs, some of which push their way toward anti-cancer or anti-inflammatory pipelines. In the realm of functional materials, the bromo group gets replaced to introduce new groups needed for electronic properties, color, or bioactivity. Other businesses tap into the compound’s structure for agrochemical and pigment manufacture, showing how modest changes to natural molecules offer new paths for research and development. Because the structure is manageable and modifications are predictable, chemists reach for it while planning synthetic routes that would otherwise be too complex or costly.
Disposal and environmental impact stand out as points of concern for any brominated organic molecule. Waste generated from reactions or cleaning must go into designated hazardous organic streams, as the molecule does not readily degrade in the environment or water. Laboratories and factories need well-established waste treatment plans to capture, neutralize, and properly destroy excess or spilled chemical. Procedures, like incineration in licensed facilities, keep releases from entering landfills or waterways. Encouraging suppliers to certify supplies and pursue greener manufacturing not only supports safety but helps set new expectations for how reagents should be produced and managed. On the bench, switching to low-dust packaging and single-use reagent bottles can drive down risk by limiting skin and respiratory exposures.
After years working with aromatic heterocycles, it’s clear that 5-Bromoindole offers more than just a synthetic shortcut. The weight of careful safety, the chance to build versatile scaffolds, and the responsibility for clean handling always follow every batch or shipment. Whether ordered in grams or kilos, researchers find new uses for it each year. Its physical and chemical rules stay consistent, so those who know its quirks can get predictable, safe, and reliable results—provided safe practices and respect for its chemistry stand at the front.
