Organic Brominated Heterocyclic Compounds: Structural Logic, Application Value, and Research Selection Guide (Tables 1–6)

I. Introduction

In organic chemistry, medicinal chemistry, materials chemistry, and natural product research, both heterocycles and brominated sites are highly frequent keywords. IUPAC defines heterocyclic compounds as cyclic compounds in which the ring contains at least two different elements; meanwhile, heteroarenes emphasize that the aromatic π-electron system is retained after heteroatoms are introduced into the ring. Based on this definition, the organic brominated heterocyclic compounds discussed in this article are compounds built on an organic heterocyclic core and bearing bromine substitution. Among them, the most important and most common class is brominated heteroarenes.

When bromine and a heterocycle are combined within the same molecule, they can simultaneously influence the molecule’s electronic properties, reactivity, downstream modifiability, and biological or materials-related functions. In other words, what is truly valued is the combination of a functional heterocyclic scaffold + a programmable C–Br site. As for the importance of heterocycles themselves, classical studies have shown that about 59% of approved small-molecule drugs contain nitrogen heterocycles, indicating that heterocyclic scaffolds are already core platforms in modern molecular design; bromination often further turns such a platform into a reactive handle that can be continually elaborated and optimized.

II. What Are Organic Brominated Heterocyclic Compounds?

Item	Core Meaning	Explanation
Organic	A covalent molecular system based on carbon	The compounds under discussion belong to organic chemistry rather than non-organic systems such as inorganic bromides.
Bromine	A bromine atom is introduced into the molecule, most commonly in the form of a C–Br bond	Bromine is not only part of the molecular structure, but also often introduces possibilities for further reaction and property tuning.
Heterocycle	The ring contains at least two different elements; in organic chemistry, common heteroatoms include N, O, and S	Such scaffolds usually differ from purely carbocyclic rings in electronic distribution, acidity/basicity, polarity, and molecular recognition behavior.
Compound	A complete molecular entity	It may serve as a synthetic intermediate, a bioactive molecule, a materials unit, or an environmentally relevant substance.
Organic brominated heterocyclic compound	Not a simple mechanical combination of “organic,” “bromine,” “heterocycle,” and “compound,” but a complete molecular category	Refers to compounds built on an organic heterocyclic core and containing bromine; the most typical subclass consists of molecules in which bromine is directly attached to the heterocyclic framework, especially brominated heteroarenes.
Typical examples	Simultaneously possess the three features of being “organic,” “heterocyclic,” and “brominated”	Such as bromopyridines, bromoindoles, bromothiophenes, bromofurans, and bromoquinolines.
Not included in this category	Do not satisfy key conditions such as “containing a heterocycle” or “containing bromine”	For example, simple bromoalkanes, bromobenzene, or heterocyclic molecules that do not contain bromine.
Additional note	Bromine does not have to be attached only to the ring	In a broader sense, bromine may also be located on a side chain while the heterocyclic core is retained; however, in research discussions and reagent supply, the main focus is more often on compounds in which bromine is directly attached to the heterocyclic framework.

III. Structural Features of Organic Brominated Heterocyclic Compounds

Structural Aspect	Core Point	Direct Impact on the Molecule
Heterocyclic scaffold	The type, number, and position of heteroatoms determine the fundamental electronic characteristics of the ring system	These factors affect electronic distribution, acidity/basicity, polarity, hydrogen-bonding ability, the way aromaticity is expressed, and the selectivity of reactive sites
Brominated site	Introduction of bromine not only changes molecular composition, but also creates a C–Br bond that can undergo further transformation	This increases the possibilities for subsequent coupling, substitution, and derivatization, and may also influence molecular recognition and interaction patterns
Combined effect of both	Organic brominated heterocycles are not simply the sum of the separate effects of “heterocycle” and “bromine”	These molecules often simultaneously possess two features: a functional scaffold and a downstream modification handle, allowing them both to carry existing functions and to support further structural expansion

IV. In What Ways Are Organic Brominated Heterocyclic Compounds Important?

Dimension of Importance	Core Significance	Key Information
Value in synthetic construction	The C–Br bond is a high-frequency reaction entry point, making subsequent coupling, substitution, and molecular expansion more accessible	These compounds are often heterocyclic intermediates that can be “further elaborated,” rather than merely final products.
Value in medicinal / agrochemical optimization	Introduction of bromine can influence a molecule’s hydrophobicity, polarizability, and certain noncovalent interaction patterns; in some cases, it may also participate in halogen bonding or alter the binding mode	They can serve not only as downstream building blocks, but may also affect activity, selectivity, and structure–activity relationships; however, whether bromine truly provides a beneficial effect still depends on the specific scaffold, substitution position, and application context.
Value in natural products and biosynthesis	Organic brominated heterocycles are not limited to synthetic systems, but are also representative in natural product chemistry and biological halogenation research	Marine-derived brominated heterocyclic natural products are particularly representative, especially bromopyrrole alkaloids; related studies have also promoted interest in halogenases and controllable biocatalytic halogenation pathways.
Value in materials design	The heterocyclic scaffold provides electronic functionality, while the brominated site facilitates subsequent coupling and conjugation extension	In many organic electronic materials, these compounds serve as common precursor units and structural extension handles.
Environmental and safety boundaries	Certain brominated compounds containing heterocyclic frameworks, as well as their transformation products, have entered studies of environmental behavior and exposure assessment	For example, some emerging heterocycle-containing brominated flame retardants have already been monitored as contaminants of environmental concern. Therefore, when evaluating such compounds, should distinguish them, rather than generalizing them as a single category.

V. Core Classification of Organic Brominated Heterocyclic Compounds

Classification Axis	Main Categories	Typical Representatives	Significance of the Classification
By heterocyclic scaffold type	Nitrogen-containing heterocycles, oxygen-containing heterocycles, sulfur-containing heterocycles, mixed heterocycles	Bromopyridines, bromoindoles; bromofurans; bromothiophenes; bromothiazoles, bromobenzothiadiazoles	This is the most fundamental classification method and best reflects differences in electronic properties, reaction characteristics, and common applications.
By bromine position	Ring-brominated, side-chain-brominated	2-Bromopyridine, 3-bromothiophene; bromomethyl-substituted heterocycles	Used to distinguish whether bromine is primarily part of the scaffold substitution pattern or mainly serves as a site for downstream transformation.
By degree of bromination	Monobrominated, polybrominated	Monobromoindoles, monobromothiophenes; dibromothiophenes, polybromopyrroles	Used to judge the number of positions available for further modification and the complexity of subsequent reactions.
By scaffold level	Monocyclic heterocycles, fused/annulated heterocycles	Bromopyridines, bromothiophenes; bromoindoles, bromoquinolines, bromobenzothiophenes	Used to distinguish basic building blocks from more complex functional scaffolds.
By aromaticity	Aromatic heterocycles, partially hydrogenated heterocycles, saturated heterocycles	Bromopyridines, bromothiophenes; brominated dihydro-heterocycles; brominated piperidine derivatives	Used to further explain differences in electron delocalization, stability, and reactivity.

VI. What Practical Problems Do Organic Brominated Heterocyclic Compounds Mainly Help Solve in Research?

Research Need or Problem	What Organic Brominated Heterocyclic Compounds Can Do	Typical Value
A need to further extend a heterocyclic scaffold	Provide a C–Br site that can undergo further coupling or substitution	Facilitates subsequent construction through Suzuki, Stille, Negishi, Buchwald–Hartwig, and related reactions, allowing simple heterocycles to be expanded into more complex molecules.
A need to perform SAR optimization while retaining an active heterocyclic scaffold	Serve as an adjustable substituent variable that can alter hydrophobicity, polarizability, steric occupancy, and some modes of molecular recognition	Suitable for SAR optimization in medicinal chemistry and agrochemistry, but introducing bromine does not necessarily guarantee improved activity.
A need to convert natural-product-inspired activity clues into researchable and synthetically accessible molecular platforms	Provide structural templates connected to marine brominated heterocyclic natural products	Helps link natural product inspiration, activity studies, and synthetic modification, especially in research involving brominated pyrrole-type compounds.
A need to construct longer conjugated skeletons or functional materials units	Make heteroatom-containing electronically functional scaffolds easier to incorporate into downstream coupling and monomer assembly	Commonly seen in the design of materials precursors such as thiophenes and benzothiadiazoles, for the construction of organic photovoltaic and organic semiconductor molecules.

Additional Note:

Whether an organic brominated heterocycle is suitable for direct use in a coupling route does not depend only on the fact that it is “a brominated compound.” Actual reaction performance is also closely related to the heterocycle type, the position of the bromine atom, the coordination or deactivating effects introduced by heteroatoms, as well as the catalyst, ligand, base, and solvent system. For polyhalogenated or multi-site heteroarenes, site selectivity also requires special attention. Therefore, in route design, a more reliable approach is not to regard organic brominated heterocycles simply as “general-purpose coupling substrates,” but to evaluate them one by one in light of the specific scaffold and the target transformation.

VII. Product Navigation for Organic Brominated Heterocyclic Compounds: Quickly Locate Tables 1–6 by Research Task

Research Task / Experimental Need	Recommended Table to Check First	Key Product Types to Focus On	Navigation Notes
Need the most basic brominated heterocyclic building blocks for routine coupling reactions such as Suzuki, Sonogashira, Buchwald–Hartwig, or post-metalation transformations	Table 1	Basic five-membered brominated heterocycles, such as bromothiophenes, bromothiazoles, bromopyrazoles, bromoimidazoles, bromofurans, bromopyrroles, etc.	Table 1 collects products that are closest to “general-purpose starting materials.” It is most suitable for structural extension starting from the simplest brominated heterocyclic substrates, and is the first table to consult for heterocycle stitching, preliminary route screening, and scaffold replacement.
Need to use both the “brominated site + another reactive site” for tandem design, for example when subsequent amidation, ester hydrolysis, condensation, reductive amination, cyclization, etc. are also required	Table 2	Five-membered brominated heterocyclic intermediates bearing carboxylic acid, ester, aldehyde, amino, boronic acid, and related functional groups	Table 2 is best suited to scenarios where the goal is not just a single coupling step. The products here can usually use the brominated site for cross-coupling while retaining a second reaction handle, making them suitable for multistep synthesis, functionalized intermediate construction, and improved route convergence.
Need to introduce six-membered nitrogen heterocycles such as pyridines, pyrimidines, pyrazines, pyridazines, quinolines, and isoquinolines for medicinal chemistry, ligand design, or electron-deficient scaffold construction	Table 3	Six-membered nitrogen heterocycles and their amino-substituted derivatives	Table 3 is suitable for any task in which the target molecule requires a six-membered aza-aromatic core. These scaffolds are very common in medicinal chemistry and are also frequently used to tune basicity, polarity, coordination ability, and electronic properties, so this table is often a priority in lead optimization.
Need high-frequency medicinal chemistry scaffolds such as indoles, indazoles, and azaindoles for SAR optimization, site-selective modification, or natural-product-like scaffold expansion	Table 4	Bromoindoles, bromoindazoles, azaindoles, and their 3-carboxylic acid / aldehyde intermediates	Table 4 focuses on a particularly common group of fused nitrogen-containing heterocycles in medicinal chemistry. If the research emphasis is on indole-based lead compounds, kinase-inhibitor-like scaffolds, natural-product analogues, or regioisomer comparison, this is the most targeted table.
Need more rigid and more fused aromatic heterocyclic scaffolds such as benzothiazoles, benzothiophenes, benzofurans, carbazoles, and thienothiophenes for medicinal chemistry, fluorescent molecules, or functional molecule design	Table 5	Other fused aromatic heterocyclic brominated building blocks	Table 5 is more suitable for cases where the target is no longer a simple monocyclic heterocycle, but a larger, flatter, and more rigid fused scaffold. These products are often used to construct molecules with stronger hydrophobicity, higher planarity, or stronger π-conjugation characteristics.
Need molecular and monomer design for organic semiconductors, conjugated polymers, D–A materials, and OFET / OPV / OLED-related systems	Table 6	Alkylated bromothiophenes, dibromothiophenes, benzothiadiazole-based materials monomers, and D–A conjugated units	Table 6 is the most materials-chemistry-oriented, and is especially suitable for identifying monomers that can undergo further polymerization or double coupling. If the goal is conjugated main-chain extension, acceptor-unit introduction, side-chain tuning, or donor–acceptor combination, this is the most direct table to check first.
Want to find “dibromo-site” products for double-end coupling, polymerization, or rapid extension of a conjugated backbone	Tables 1 and 6	Dibromothiophenes, dibromobenzothiadiazoles, dibrominated D–A monomers, etc.	If the main goal is to find products with “two further-reactive sites in one molecule,” Table 6 should be checked first for materials-related work; for more basic small dibromothiophene-type building blocks, Table 1 should also be consulted.
Want to find “amino + bromine” bifunctional products that retain the heterocyclic core while still allowing condensation / cyclization / coupling	Tables 2, 3, and 5	Aminobromopyridines, aminobromopyrazoles, aminobromothiadiazoles, aminobromobenzothiazoles, etc.	These products are highly suitable for medicinal chemistry intermediates or deep derivatization of heterocycles. If the scaffold is a five-membered heterocycle, check Table 2 first; if it is a six-membered aza-heterocycle, check Table 3 first; if it is a fused benzothiazole-type scaffold, then also consult Table 5.
Want to find “aldehyde / acid / ester”-type brominated heterocycles for subsequent condensation, amidation, transesterification, reductive amination, or one-pot tandem reactions	Table 2	Brominated intermediates of furans, thiophenes, indoles, etc. bearing carboxylic acid, ester, or aldehyde groups	The essence of this need is not to find the simplest brominated substrate, but to find intermediates with greater downstream transformation space. Therefore, Table 2 is especially useful, particularly during route design and intermediate optimization stages.
Still unsure which heterocycle class to choose, and just want to build an initial screening pool starting from common and broadly useful organic brominated heterocycles	Tables 1 and 3	Basic five-membered heterocycles + basic six-membered aza-heterocyclic building blocks	If you are at an early-stage screening stage, Tables 1 and 3 are usually the most effective starting points. The former covers high-frequency five-membered heterocycles, and the latter covers high-frequency six-membered nitrogen heterocycles; together they are ideal for building an initial “candidate scaffold pool.”

Table 1 | Basic Five-Membered Brominated Heterocyclic Building Blocks

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Brominated five-membered sulfur/nitrogen monoheterocyclic building block (thiazole type)	3034-53-5	B123649	2-Bromothiazole	≥99%	A typical brominated thiazole building block, commonly used in coupling reactions such as Suzuki, Sonogashira, and amination, and further employed to construct thiazole motifs in pharmaceuticals, agrochemicals, and functional molecules.
Brominated five-membered diaza heterocyclic building block (pyrazole type)	2075-45-8	B119149	4-Bromopyrazole	≥99%	The pyrazole scaffold is a common medicinal chemistry heterocycle. The brominated site enables site-specific coupling or further functionalization, making it suitable for bioactive molecules, ligands, and heterocycle library expansion.
Brominated five-membered oxygen/nitrogen monoheterocyclic building block (oxazole type)	125533-82-6	B586790	2-Bromooxazole	≥98%	Oxazole is a common motif in medicinal chemistry and natural product mimicry. The 2-bromo derivative is suitable for site-specific coupling or for the further introduction of aryl / heteroaryl substituents.
Basic bromothiophene building block (2-position)	1003-09-4	B107006	2-Bromothiophene	≥98%	One of the most fundamental brominated thiophene building blocks, suitable for various coupling reactions, metalation, and subsequent functionalization. It is a high-frequency intermediate in thiophene-based medicinal chemistry and materials chemistry.
Brominated five-membered oxygen/nitrogen monoheterocyclic building block (isoxazole type)	111454-71-8	B481858	3-Bromo-isoxazole	≥97%	Isoxazole is commonly found in pharmaceutical and agrochemical scaffolds. The 3-bromo derivative is convenient for site-selective coupling or further functionalization, and is used in the construction of oxygen/nitrogen-containing five-membered heterocyclic derivatives.
Basic bromofuran building block (3-position)	22037-28-1	B123116	3-Bromofuran	≥97%	A basic 3-bromofuran building block suitable for coupling, metalation, and downstream derivatization. It is a commonly used intermediate in medicinal chemistry, natural-product analogues, and fine chemical synthesis.
Basic bromothiophene building block (3-position)	872-31-1	B103164	3-Bromothiophene	≥97%	One of the most fundamental 3-bromothiophenes, suitable for various cross-coupling reactions, post-lithiation transformations, and the construction of polysubstituted thiophenes. It is a high-frequency intermediate in medicinal chemistry and materials chemistry.
Basic bromoimidazole building block (4-position)	2302-25-2	B119330	4-Bromo-1H-imidazole	≥97%	The imidazole scaffold is very common in pharmaceuticals, coordination chemistry, and bio-related chemistry. The 4-bromo derivative is suitable for site-specific coupling and substitution, and is used to build polysubstituted imidazole derivatives.
Brominated five-membered sulfur/nitrogen monoheterocyclic building block (thiazole type)	34259-99-9	B122730	4-Bromothiazole	≥97%	A basic 4-bromothiazole building block suitable for Suzuki, Sonogashira, Buchwald–Hartwig, and related reactions. It is a common thiazole-containing intermediate in medicinal chemistry and agrochemistry.
N-substituted brominated imidazole building block	1003-21-0	B165351	5-Bromo-1-methyl-1H-imidazole	≥97%	N-Methylation can alter polarity and electronic properties, while bromination at the 5-position facilitates further coupling. It is a common intermediate in drug design and the synthesis of functional imidazole derivatives.
Dibromothiophene double-coupling building block	3141-27-3	D100660	2,5-Dibromothiophene	≥96%	The two brominated sites allow double-end coupling, making this an important basic monomer for constructing symmetrical thiophene derivatives, oligothiophenes, and conjugated polymers.
Alkyl-substituted bromothiazole building block	7238-61-1	B123638	2-Bromo-4-methylthiazole	≥96%	Methyl substitution can tune the electronic properties and hydrophobicity of the thiazole ring, while the 2-bromo site facilitates further coupling. It is suitable for constructing thiazole-containing motifs in medicinal chemistry and agrochemistry.
Basic bromopyrrole building block (2-position)	38480-28-3	B1036585	2-Bromopyrrole	≥95%	2-Bromopyrrole is a basic starting material for constructing polysubstituted pyrroles, fused-ring systems, and natural-product-like molecules, and is suitable for coupling and further functionalization.
Basic bromopyrrole building block (3-position)	87630-40-8	B1069219	3-Bromo-1H-pyrrole	≥95%	Bromination at the 3-position provides a regioselective modification pathway different from that of the 2-position, making it suitable for synthesizing positional isomeric pyrrole derivatives and complex heterocyclic frameworks.
Basic bromofuran building block (2-position)	584-12-3	B665004	2-Bromofuran	≥93%	A basic 2-bromofuran building block suitable for coupling, post-metalation transformations, and the synthesis of polysubstituted furans. It is a commonly used raw material in organic synthesis and heterocyclic chemistry.

Table 2 | Functionalized Five-Membered Brominated Heterocyclic Intermediates (Acids, Esters, Aldehydes, Amines, Boronic Acids)

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Brominated furan functionalized intermediate (carboxylic acid type)	585-70-6	B139036	5-Bromo-2-furoic acid	≥98% (HPLC)	Contains both a brominated site and a carboxylic acid functionality, enabling not only coupling reactions but also amidation / esterification. It is an important intermediate for constructing brominated furan derivatives.
Brominated pyrrole functionalized intermediate (ester type)	934-05-4	M139460	Methyl 4-bromopyrrole-2-carboxylate	≥98% (HPLC)	Combines a brominated site with an ester functionality, making it suitable for site-selective expansion on the pyrrole ring. Commonly used in the synthesis of natural-product-like molecules, drug leads, and polysubstituted pyrroles.
Brominated thiophene functionalized intermediate (carboxylic acid type)	7311-64-0	B153084	3-Bromothiophene-2-carboxylic Acid	≥98% (GC)	The thiophene ring bears both a brominated site and a carboxylic acid group, facilitating coupling and acyl-derived transformations. Commonly found in pharmaceutical intermediates, thiophene-based functional materials, and heterocycle extension synthesis.
Brominated thiazole functionalized intermediate (carboxylic acid type)	5198-88-9	B152754	2-Bromothiazole-4-carboxylic Acid	≥98%	Combines a brominated thiazole site with a carboxylic acid group, making it convenient for coupling, condensation, and amidation. It is a common building block for thiazole-containing pharmaceutical and agrochemical intermediates.
Brominated furan functionalized intermediate (ester type)	2527-99-3	M137548	5-Bromo-2-furoic Acid Methyl Ester	≥98%	Contains both a brominated site and an ester group, and is suitable for further coupling, ester hydrolysis, or acyl transformation. It is a commonly used intermediate for the synthesis of polysubstituted furan derivatives.
Brominated furan functionalized intermediate (aldehyde type)	1899-24-7	B111879	5-Bromo-2-furaldehyde	≥98%	A key furan aldehyde intermediate. The brominated site can be used for coupling, while the aldehyde group can participate in condensation, reduction, or cyclization. Commonly used in the synthesis of bioactive heterocycles and fine chemicals.
Brominated thiophene functionalized intermediate (ester type)	26137-08-6	M157924	Methyl 3-Bromothiophene-2-carboxylate	≥97% (GC)	Combines a brominated thiophene site with an ester functionality, making it suitable for coupling, ester hydrolysis, and further derivatization. It is a common starting material for thiophene-based medicinal chemistry and materials intermediates.
Brominated thiazole functionalized intermediate (carboxylic acid type)	54045-76-0	B119304	2-Bromothiazole-5-carboxylic acid	≥97%	Contains both a brominated site and a carboxylic acid group, allowing it to serve both coupling reactions and amidation / esterification. It is an important intermediate for constructing highly functionalized thiazole derivatives.
Aminobromopyrazole intermediate	16461-94-2	A133246	3-Amino-4-bromopyrazole	≥97%	Pyrazoles are frequently used in medicinal chemistry. The amino group is useful for condensation and ring formation, while the brominated site facilitates cross-coupling. Suitable for kinase inhibitor research, heterocycle libraries, and lead compound modification.
Brominated furan functionalized intermediate (aldehyde type)	21921-76-6	B151893	4-Bromo-2-furaldehyde	≥97%	Possesses both a brominated site and an aldehyde group, allowing participation in coupling as well as condensation, reductive amination, and heterocycle annulation. It is a practical intermediate for building functionalized furan compounds.
Brominated furan functionalized intermediate (ester type)	6132-37-2	E331006	Ethyl 5-bromofuran-2-carboxylate	≥97%	Combines a brominated site and an ester group, facilitating coupling, hydrolysis, and further acyl derivatization. It is a useful intermediate for the synthesis of polysubstituted furan compounds.
Brominated thiophene functionalized intermediate (aldehyde type)	4701-17-1	B101864	5-Bromo-2-thiophenecarboxaldehyde	≥97%	The brominated site can undergo cross-coupling, while the aldehyde group can participate in condensation, reduction, or cyclization. It is a common raw material in thiophene-based medicinal chemistry intermediates and conjugated molecule construction.
Brominated furan functionalized intermediate (aldehyde type)	14757-78-9	B181580	3-Bromo-2-formylfuran	≥96%	The brominated site and formyl group together provide high synthetic reactivity, making this compound suitable for coupling, condensation, and cyclization. It is an important functionalized furan intermediate in fine chemicals and heterocycle synthesis.
Brominated thiophene functionalized intermediate (aldehyde type)	930-96-1	B123868	3-Bromothiophene-2-carboxaldehyde	≥96%	Possesses both a brominated site and an aldehyde group, making it suitable for tandem cross-coupling / condensation design. Commonly used in thiophene medicinal chemistry intermediates and conjugated fragment synthesis.
Aminobromothiadiazole intermediate	37566-39-5	A138762	2-Amino-5-bromo-1,3,4-thiadiazole	≥95% (HPLC)	Thiadiazole is a typical electron-deficient five-membered heterocycle. The amino group and brominated site facilitate further condensation, coupling, and heterocycle extension, and are commonly used in the design of bioactive scaffolds in medicinal chemistry and agrochemistry.
Brominated thiophene bifunctional coupling building block (boronic acid type)	162607-17-2	B167711	5-Bromo-2-thienylboronic acid (contains varying amounts of Anhydride)	≥95%	Contains both a boronic acid group and a brominated site, making it a typical AB-type thiophene building block. Suitable for sequential coupling or polymerization reactions, and highly valuable in the synthesis of conjugated materials, oligothiophenes, and functional molecules.

Table 3 | Six-Membered Aza-Aromatic Building Blocks, Their Aminated Derivatives, and Related Fused Scaffolds

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Basic bromopyridine building block (2-position)	109-04-6	B109679	2-Bromopyridine	≥98%	One of the most commonly used bromopyridine building blocks, suitable for Suzuki, Negishi, amination, and related couplings, and used for introducing 2-pyridyl fragments.
Aminobromopyrimidine intermediate	7752-82-1	A123409	2-Amino-5-bromopyrimidine	≥98%	The amino group and brominated site can participate separately in condensation and coupling reactions. It is a common intermediate for nucleobase analogues, kinase inhibitors, and pyrimidine-based medicinal chemistry molecules.
Basic bromopyrimidine building block (2-position)	4595-60-2	B120301	2-Bromopyrimidine	≥98%	An electron-deficient heteroaromatic substrate commonly used in cross-coupling, nucleophilic substitution, and heterocycle assembly. It is a common pyrimidine intermediate in medicinal chemistry.
Basic bromopyridine building block (3-position)	626-55-1	B106977	3-Bromopyridine	≥98%	A commonly used reagent for introducing 3-pyridyl fragments, suitable for Pd/Ni-catalyzed coupling and multistep heterocycle assembly. Widely used in medicinal chemistry, agrochemistry, and ligand synthesis.
Basic bromopyridine building block (4-position hydrochloride)	19524-06-2	B102732	4-Bromopyridine Hydrochloride	≥98%	A commonly used reagent for introducing 4-pyridyl fragments. The hydrochloride form facilitates storage and handling, and is suitable for coupling, substitution, and pharmaceutical intermediate synthesis.
Basic bromopyrimidine building block (5-position)	4595-59-9	B107005	5-Bromopyrimidine	≥98%	A common electron-deficient heterocyclic building block suitable for cross-coupling and heterocycle assembly. It is an important basic starting material for many pyrimidine-containing bioactive molecules.
Aminobromopyridine intermediate	13534-99-1	A167068	2-Amino-3-bromopyridine	≥97%	Contains both an amino group and a brominated site, making it suitable for condensation, cyclization, and cross-coupling. It is a commonly used building block in medicinal chemistry, agrochemical intermediates, and nitrogen heterocycle extension synthesis.
Basic bromopyrazine building block	56423-63-3	B135014	2-Bromopyrazine	≥97%	Pyrazine is an electron-deficient diaza six-membered heterocycle. The 2-bromo derivative is suitable for Suzuki coupling, amination, and nucleophilic substitution, and is commonly used in the construction of pharmaceuticals, ligands, and functional heterocycles.
Aminobromopyridine intermediate	13534-97-9	A101199	3-Amino-6-bromopyridine	≥97%	Contains both a reactive amino group and a coupling-capable brominated site, making it a practical raw material for the construction of polysubstituted pyridines, pharmaceutical intermediates, and fused nitrogen-containing heterocycles.
Basic bromopyridazine building block	88491-61-6	B590520	3-Bromopyridazine	≥97%	Pyridazine is an important diaza six-membered heterocycle. Its brominated site is suitable for further arylation, amination, and heterocycle assembly, and is commonly used in medicinal chemistry and nitrogen-containing aromatic heterocycle design.
Fused six-membered aza-aromatic brominated building block (isoquinoline type)	1532-97-4	B123611	4-Bromoisoquinoline	≥98% (GC)	Isoquinoline is an important medicinal chemistry scaffold. The 4-bromo derivative is commonly used as a cross-coupling substrate for constructing substituted isoquinoline derivatives and heterocyclic lead compounds.
Fused six-membered aza-aromatic brominated building block (quinoline type)	5332-24-1	B113800	3-Bromoquinoline	≥98%	The quinoline scaffold has important medicinal chemistry value. The 3-bromo derivative is suitable for further arylation, heteroarylation, and functional group extension.
Fused six-membered aza-aromatic brominated building block (quinoline type)	4964-71-0	B120007	5-Bromoquinoline	≥97%	Quinoline is a classic medicinal chemistry scaffold. The 5-bromo derivative is suitable for regioselective coupling and subsequent functionalization, and is used for constructing substituted quinolines and their bioactive derivatives.
Fused six-membered aza-aromatic brominated building block (quinoline type)	5332-25-2	B101593	6-Bromoquinoline	≥96%	6-Bromoquinoline is suitable for regioselective coupling and functionalization, and is commonly used for constructing bioactive quinoline derivatives, ligands, and fluorescent molecules.

Table 4 | Brominated Building Blocks and Intermediates of Indole / Indazole / Azaindole Series

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Basic bromoindole building block (4-position)	52488-36-5	B111478	4-Bromoindole	≥98%	Indole is a high-frequency scaffold in medicinal chemistry and natural products. The 4-bromo derivative is suitable for site-selective coupling and is used to construct substituted indole lead compounds.
Basic bromoindole building block (5-position)	10075-50-0	B111473	5-Bromoindole	≥98%	5-Bromoindole is a common medicinal chemistry intermediate, suitable for the site-specific introduction of aryl, alkynyl, amino, and other substituents while retaining the indole core.
Functionalized bromoindole intermediate (3-carboxylic acid type)	10406-06-1	B152540	5-Bromoindole-3-carboxylic Acid	≥98%	Possesses both a brominated indole site and a 3-carboxylic acid group, making it suitable for combined coupling and amidation. It is a practical intermediate for constructing highly functionalized indole molecules.
Functionalized bromoindole intermediate (3-aldehyde type)	877-03-2	B122982	5-Bromoindole-3-carboxaldehyde	≥98%	The brominated site can undergo cross-coupling, while the aldehyde group can participate in condensation, reductive amination, and heterocycle annulation. It is suitable for modification of drug leads and natural-product-like scaffolds.
Basic bromoindole building block (6-position)	52415-29-9	B123498	6-Bromoindole	≥98%	Bromination at the 6-position provides a clear modification site for indole SAR optimization and is suitable for constructing regioisomeric substituted indole compounds.
Basic bromoindole building block (7-position)	51417-51-7	B119150	7-Bromoindole	≥98%	The 7-bromo derivative is suitable for regioselective structural modification and is common in indole medicinal chemistry and natural-product analogue synthesis.
Fused diaza heterocyclic brominated building block (indazole type)	53857-57-1	B122429	5-Bromo-1H-indazole	≥97%	Indazole is a high-frequency scaffold in medicinal chemistry. The 5-bromo derivative is commonly used for SAR optimization and expansion of substitution patterns, and can be further developed into kinase-inhibitor-like molecules.
Fused nitrogen-containing heterocyclic brominated building block (azaindole type)	348640-06-2	B122933	4-Bromo-7-azaindole	≥96%	Azaindole combines an indole-like planar scaffold with a pyridine-type nitrogen atom, making it an important scaffold in medicinal chemistry. Bromination at the 4-position is beneficial for SAR modification and heterocycle assembly.

Table 5 | Other Fused Aromatic Heterocyclic Brominated Building Blocks (Benzothiazoles, Benzothiophenes, Benzofurans, Carbazoles, etc.)

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Fused nitrogen-containing aromatic heterocyclic brominated building block (carbazole type)	3652-90-2	B152010	2-Bromocarbazole	≥98%	The carbazole scaffold is commonly used in luminescent materials, hole-transport materials, and medicinal chemistry research. The 2-bromo derivative facilitates further construction of substituted carbazole π-conjugated systems.
Fused thiophene-type π-conjugated brominated building block	25121-81-7	B152935	2-Bromothieno[2,3-b]thiophene	≥98%	A rigid fused sulfur-containing scaffold suitable for constructing highly conjugated, planarized π-systems. Commonly used in the synthesis of organic semiconductors, conjugated polymers, and functional materials.
Fused oxygen/nitrogen-containing aromatic heterocyclic brominated building block (benzoxazole type)	132244-31-6	B166962	5-Bromo-1,3-benzoxazole	≥98%	Benzoxazole combines aromaticity with heteroatom recognition features. The brominated site is suitable for further coupling, and the scaffold is commonly used in medicinal chemistry, fluorescent probes, and functional molecule design.
Fused sulfur-containing aromatic heterocyclic brominated building block (benzothiophene type)	4923-87-9	B101866	5-Bromobenzo[b]thiophene	≥98%	The benzothiophene scaffold combines hydrophobic aromaticity with sulfur-containing character. The brominated site is suitable for further coupling and is commonly used in medicinal chemistry and organic electronic materials research.
Fused sulfur/nitrogen-containing aromatic heterocyclic brominated building block (benzothiazole type)	768-11-6	B186512	5-Bromobenzothiazole	≥98%	Benzothiazole is a common scaffold in medicinal chemistry and probe design. The 5-bromo derivative is suitable for site-specific modification and is used in activity screening, fluorescent molecule synthesis, and functional material construction.
Fused sulfur/nitrogen-containing aromatic heterocyclic brominated building block (benzothiazole type)	53218-26-1	B135001	6-Bromobenzothiazole	≥98%	6-Bromobenzothiazole is suitable for downstream coupling and functionalization, and is commonly used in pharmaceutical intermediates, fluorescent heterocycles, and coordination-type molecule synthesis.
Aminobromobenzothiazole intermediate	15864-32-1	A134312	2-Amino-6-bromobenzothiazole	≥97% (T)	The amino group facilitates condensation and ring formation, while the brominated site is convenient for coupling and extension. It is a practical intermediate for constructing highly functionalized benzothiazole medicinal chemistry molecules and probe molecules.
Fused oxygen-containing aromatic heterocyclic brominated building block (benzofuran type)	23145-07-5	B168831	5-Bromobenzofuran	≥97%	Benzofuran combines aromatic planarity with oxygen-containing heterocyclic character. The 5-bromo derivative is suitable for coupling-based extension and is commonly used in medicinal chemistry, natural-product analogues, and functional molecule design.
Fused sulfur-containing aromatic heterocyclic brominated building block (benzothiophene type)	5394-13-8	B185084	2-Bromobenzo[b]thiophene	≥96%	Benzothiophene is a common scaffold in medicinal chemistry and organic electronic materials. The 2-bromo derivative is advantageous for regioselective coupling and can be used to construct substituted fused sulfur-containing aromatic heterocycles.
Fused sulfur/nitrogen-containing aromatic heterocyclic brominated building block (benzothiazole type)	2516-40-7	B152752	2-Bromobenzothiazole	≥95% (GC)	Benzothiazole is a high-frequency scaffold in medicinal chemistry and fluorescent functional molecules. The 2-bromo derivative is suitable for coupling, substitution, and the further construction of polysubstituted benzothiazole molecules.

Table 6 | Brominated Monomers Related to Organic Electronic Materials

Classification	CAS No.	Aladdin Catalog No.	Name	Specification or Purity	Product Features and Applications
Alkylated bromothiophene materials monomer	69249-61-2	B100758	2-Bromo-3-hexylthiophene	≥98%	A typical organic electronic materials monomer, commonly used in the construction of polythiophenes, oligothiophenes, and head-to-tail regioregular conjugated systems. Widely seen in OFET, OPV, and OLED-related research.
Dibrominated acceptor-type fused heterocyclic materials monomer	15155-41-6	D102051	4,7-Dibromo-2,1,3-benzothiadiazole	≥98%	A classic acceptor-type conjugated unit. The brominated sites at both ends facilitate double coupling, and the compound is widely used in D–A conjugated polymers, small-molecule semiconductors, and organic photovoltaic materials.
Alkylated dibromothiophene materials monomer	116971-11-0	D100774	2,5-Dibromo-3-hexylthiophene	≥97%	A typical A2-type brominated thiophene monomer, commonly used in Stille, Suzuki, Kumada, and related polymerization or coupling reactions. Widely applied in research on polythiophenes, conjugated polymers, organic field-effect transistors, and optoelectronic materials.
Acceptor–donor-type brominated conjugated materials monomer	457931-23-6	B152468	4,7-Bis(5-bromo-4-n-octyl-2-thienyl)-2,1,3-benzothiadiazole	≥97%	The combination of a benzothiadiazole acceptor and an alkylthiophene donor forms a classic D–A conjugated unit. The terminal brominated sites facilitate further polymerization or extension, and the compound is commonly used in organic photovoltaics, field-effect devices, and near-infrared materials research.
Dibrominated acceptor-type fused heterocyclic materials monomer	18392-81-9	D156010	5,6-Dibromo-2,1,3-benzothiadiazole	≥97%	The two brominated sites enable further double coupling. As a strong acceptor unit, benzothiadiazole is commonly used to construct D–A conjugated polymers, small-molecule acceptors, and organic electronic materials.
Acceptor–donor-type brominated conjugated materials monomer	288071-87-4	B136537	4,7-Bis(5-bromo-2-thienyl)-2,1,3-benzothiadiazole	≥95% (HPLC)	A classic D–A conjugated unit. The terminal brominated sites are suitable for further polymerization or conjugation-chain extension, and the compound is commonly used in research on organic photovoltaics, luminescent materials, and charge-transport materials.

Note: The above are representative Aladdin products. For more product specifications, please refer to the product list at the end of the article or search the Aladdin website using the “product name / CAS / catalog number.”

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