2-Amino-5-bromobenzothiazole: Properties, Handling & Lab Use

2-Amino-5-bromobenzothiazole is a halogenated benzothiazole heterocycle widely employed as a versatile building block in medicinal chemistry, agrochemical research, and the synthesis of biologically active compounds.

CAS Number

1747-90-6

Molecular Formula

C7H5BrN2S

Molecular Weight

229.09 g/mol

Appearance

Off-white to pale yellow crystalline solid

Melting Point

Approximately 224–228 °C (review recommended)

Solubility

Soluble in DMSO, DMF, and ethanol; sparingly soluble in water

Storage Condition

Store in a cool, dry, well-ventilated area away from light

Aladdin SKU

A119305

Chemical Identity and Structure

2-Amino-5-bromobenzothiazole (CAS 1747-90-6) belongs to the benzothiazole family of 1,3-fused bicyclic heterocycles containing both sulfur and nitrogen atoms. The compound features an amino group at the 2-position of the thiazole ring and a bromine substituent at the 5-position of the fused benzene ring. This dual functionality—a nucleophilic amine and an electrophilic C–Br bond—makes the molecule a particularly powerful bifunctional scaffold for elaboration via complementary reaction pathways.

The aromatic benzothiazole core confers planar geometry and moderate electron density, while the electron-withdrawing inductive effect of bromine slightly polarizes the ring system. The 2-amino group can participate in condensation, acylation, and cyclization reactions, whereas the aryl bromide is well suited for transition-metal-catalyzed cross-coupling reactions such as Suzuki–Miyaura, Buchwald–Hartwig, and Sonogashira couplings.

Applications in Synthesis and Medicinal Chemistry

The benzothiazole scaffold is recognized as a privileged structure in drug discovery because it appears in numerous bioactive molecules with antibacterial, antifungal, antitumor, anticonvulsant, and anti-inflammatory activities. 2-Amino-5-bromobenzothiazole serves as a key intermediate that allows researchers to introduce structural diversity at two independent sites:

• C–Br functionalization: Palladium- or copper-catalyzed cross-coupling reactions at the 5-bromo position enable introduction of aryl, heteroaryl, vinyl, or alkynyl groups, rapidly expanding chemical space.
• Amino group derivatization: The 2-amino group can be converted to amides, sulfonamides, ureas, thioureas, Schiff bases, and heterocyclic fusions, all of which modulate biological activity.
• Dual functionalization: Sequential modification at both sites generates highly complex, drug-like molecules from a single building block, reducing overall synthetic step count.

The compound is also used as a starting material in the preparation of fluorescent dyes, ligands for metal coordination chemistry, and agrochemical candidates.

Safe Handling, Storage, and Disposal

Although 2-Amino-5-bromobenzothiazole is a solid reagent with relatively low volatility, standard laboratory precautions are mandatory. Researchers must consult the current Safety Data Sheet (SDS) before use.

Personal Protective Equipment (PPE): Wear chemical-resistant gloves (nitrile recommended), a laboratory coat, and safety goggles. Use a dust mask or work in a fume hood when weighing or transferring the powder to minimize inhalation exposure.

Storage: Store in a tightly sealed container in a cool (below 25 °C), dry, well-ventilated area away from direct light and incompatible oxidizing agents. Proper labeling and segregated storage are essential.

Disposal: Do not dispose of down the sink. Collect waste material in a labeled, sealable container and dispose of in accordance with local, regional, and national regulations for chemical waste. Incineration under controlled conditions is typically recommended for halogenated organic compounds.

First Aid: In case of skin or eye contact, rinse thoroughly with water for at least 15 minutes and seek medical advice. If ingested or inhaled, seek immediate medical attention and provide the SDS to healthcare personnel.

Practical Tips for Laboratory Use

The following guidance helps ensure reproducible results when working with 2-Amino-5-bromobenzothiazole:

• Dissolution: For reaction setup, pre-dissolve the compound in DMSO or DMF before adding to aqueous or mixed solvent systems. Direct addition to water will result in poor dissolution due to limited aqueous solubility.
• Cross-coupling reactions: The aryl bromide is reactive under standard Pd(0)/Pd(II) catalytic systems. Degassing solvents thoroughly with argon or nitrogen before use minimizes catalyst poisoning and side reactions.
• Moisture sensitivity: While not highly hygroscopic, the compound should be resealed promptly after use to prevent moisture ingress that could affect purity over time.
• Purity verification: Confirm purity by HPLC or TLC prior to use in sensitive biological assays. Aladdin supplies this reagent with a defined purity specification; check the Certificate of Analysis (CoA) included with each lot.
• Stock solutions: Prepare concentrated stock solutions in DMSO and store aliquots at –20 °C to preserve integrity for extended periods. Avoid repeated freeze–thaw cycles.

Frequently asked questions

What solvents are recommended for dissolving 2-Amino-5-bromobenzothiazole?

DMSO and DMF are the preferred solvents due to their high solvating power for this compound. Ethanol can also be used for moderate concentrations. Aqueous solubility is limited, so direct dissolution in water alone is not recommended without a co-solvent.

Can 2-Amino-5-bromobenzothiazole be used directly in Suzuki–Miyaura coupling reactions?

Yes. The aryl bromide at the 5-position is a competent electrophilic partner for palladium-catalyzed Suzuki–Miyaura coupling with boronic acids or esters. Standard Pd(PPh3)4 or Pd(dppf)Cl2 catalyst systems in the presence of a base such as K2CO3 are typically effective. Solvent degassing is strongly advised to protect the palladium catalyst.

How should 2-Amino-5-bromobenzothiazole be stored to maintain long-term stability?

Store the compound in a tightly sealed container at room temperature (below 25 °C), in a cool, dry area protected from light. For long-term storage of dissolved stock solutions, aliquot in DMSO and keep at –20 °C, avoiding repeated freeze–thaw cycles. Always verify purity via CoA before use in critical experiments.

What is the significance of the benzothiazole scaffold in drug discovery?

Benzothiazole is a privileged heterocyclic scaffold found in many clinically relevant and investigational drugs. Its planar, electron-rich ring system facilitates interactions with biological targets including enzymes and receptors. Derivatives have demonstrated antibacterial, antifungal, antitumor, anti-inflammatory, and anticonvulsant activities, making 2-amino-5-bromobenzothiazole a strategically valuable starting point for medicinal chemistry programs.

Is a Certificate of Analysis available for Aladdin's 2-Amino-5-bromobenzothiazole (A119305)?

Yes. Aladdin Scientific provides a lot-specific Certificate of Analysis (CoA) for product A119305, which details purity, appearance, and analytical test results. The CoA can be requested through the Aladdin website or from customer service at the time of ordering.

References

1. Gomez-Zaleta, B. et al. Benzothiazole-based compounds: A privileged scaffold in drug discovery. (General review — specific journal details to be verified.)
2. Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012. (Cross-coupling reactions and heterocyclic chemistry sections.)
3. Kaur, R. et al. Biological activities of benzothiazole derivatives: A comprehensive review. (General review — specific citation details to be verified.)

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.