I. Introduction
Organic chlorinated heterocyclic compounds are not a single molecule, but a broad class of compounds. They share two core features: first, a heterocycle serves as the structural core, with heteroatoms such as nitrogen, oxygen, and sulfur in the ring; second, the molecule contains one or more covalently bound chlorine atoms. From the perspective of research and compound selection, the importance of this class does not lie merely in the fact that it "contains chlorine." Rather, the heterocycle determines the molecule's electronic structure, polarity, and recognition mode, while chlorine further alters reactivity, hydrophobicity, metabolic properties, and the scope for further derivatization. Heterocycles themselves are highly important in medicinal chemistry; according to one FDA small-molecule drug statistics framework, about 60% of unique small-molecule drugs contain nitrogen heterocycles, and even higher proportions can be found in the literature when broader counting criteria are used. At the same time, looking more broadly at chlorinated drugs, more than 250 FDA-approved chlorine-containing drugs are already on the market, showing that the combination of "heterocycle + chlorine" is a structural motif that has been repeatedly validated over the long term.
Organic chlorinated heterocyclic compounds continue to attract attention because they simultaneously address three types of research needs: they can exist as final active molecules, serve as synthetic intermediates, and act as transformable handles for late-stage molecular modification in methodology development. Recent studies on regioselective chlorination of heterocycles also reflect this point: researchers aim to install chlorine directly and selectively at a late stage on complex molecules or heterocyclic scaffolds, thereby creating a transformable entry point for subsequent substitution, coupling, or property optimization.
A more accurate way to understand organic chlorinated heterocyclic compounds is that they sit at the intersection of structural design and reaction design.
Perspective | Why It Matters | What It Means for Research / Experimentation |
Heterocyclic scaffold | Heteroatoms alter electron density, basicity, polarity, and hydrogen-bonding behavior | Affects activity, solubility, coordination ability, drug-likeness, and material properties |
Chlorine substitution | Chlorine changes inductive effects, hydrophobicity, steric occupancy, and certain noncovalent interactions | Can be used to fine-tune activity, stability, and conformation, and can also serve as a downstream transformation site |
Combined effect | The effects are not simply additive; site selectivity and structural differences can be amplified | Even among compounds all described as "chlorinated heterocycles," reactivity can differ greatly from one scaffold to another |
II. Basic Concept: What Is Meant by "Organic Chlorinated Heterocyclic Compounds"
General definition: any compound built around an organic heterocycle and bearing one or more chlorine substitution sites can be included in this category. It covers both active molecules that retain chlorine in the final structure and intermediates in which chlorine mainly serves as a downstream reaction site.
Type | Typical Understanding | Example | Common Role in Research |
Chlorine retained in the final active molecule | Chlorine is part of the final structure | Chloroquine, chlorpromazine, atrazine | Drug, pesticide, active lead, or reference compound |
Chlorine mainly used as a downstream transformation site | Chlorine facilitates subsequent substitution or coupling | 2,4-Dichloropyrimidine, cyanuric chloride | Synthetic building block, library-synthesis intermediate, linking platform |
Chlorine plays both roles | It affects properties and is also a site for further modification | Polychlorinated pyrimidines, chloropyridines, chlorotriazines | A bifunctional node in structure optimization and route design |
III. Structural Features: What Mainly Determines the Characteristics of These Compounds
1. The heterocyclic scaffold first determines the fundamental properties of the molecule
A heterocycle is not merely a simple substitute for an ordinary aromatic ring. Nitrogen, oxygen, and sulfur atoms in the ring alter the overall scaffold's electronic distribution, aromaticity, basicity, and hydrogen-bonding characteristics. As a result, the same chlorine atom can have very different effects when placed on pyridine, pyrimidine, triazine, quinoline, or thiazine scaffolds. Heterocycles occupy such an important place in medicinal chemistry precisely because they can effectively tune solubility, lipophilicity, polarity, and hydrogen-bonding capacity.
2. Chlorine substitution further modulates molecular properties and reactivity
In organic molecules, chlorine commonly brings several effects:
1) it changes the electronic environment of nearby positions through an inductive effect;
2) it increases hydrophobicity to some extent and adds steric occupancy;
3) under suitable conditions, it can participate in halogen-bond-related interactions. According to the IUPAC definition of halogen bonding, an electrophilic region associated with the extension of a covalent bond on a halogen atom can form a net attractive interaction with a nucleophilic region in another molecule or in the same molecule. For drug design, this means that chlorine is sometimes more than just a "space-filling substituent"; under appropriate receptor environments, spatial orientations, and microenvironments, it may also participate in halogen-bond-related interactions, although such interactions are usually weaker than those involving bromine or iodine.
3. The C–Cl bond may either remain in the molecule or be used in downstream reactions
Chlorine does not play only one role in organic molecules. Reviews have pointed out that chlorine can leave as chloride in substitution and elimination processes, and it can also influence the reactivity of adjacent positions through electronic effects. This is especially important for organic chlorinated heterocycles: on strongly electron-deficient heterocycles, chlorine often serves as an entry point for subsequent nucleophilic substitution or coupling; on other scaffolds, however, it may mainly serve to tune properties rather than act as an easily leaving group.
4. Different chlorinated heterocycles can vary greatly in properties and reactivity
Not all organic chlorinated heterocycles are equally reactive. In coupling reactions, for example, aryl chlorides or heteroaryl chlorides are often more difficult to couple than their corresponding bromides or iodides, and they frequently require stronger catalytic systems, higher temperatures, or more carefully designed ligands.
Polychlorinated nitrogen heterocycles represented by 2,4-dichloropyrimidine often show a preference for reaction at C4 under many classical SNAr, amination, or cross-coupling conditions. However, this site selectivity is not absolute; it can also be affected by substituents on the ring, the nucleophile, the catalyst, the ligand, and the reaction conditions. In recent years, unconventional C2-selective coupling methods have also been developed.
IV. In Which Fields Are They Commonly Used, and What Roles Do They Play
Application Field | Representative Example | Main Role |
Medicinal chemistry and drug discovery | Chloroquine, chlorpromazine, various chloropyrimidine / chloroquinoline leads | Serves as the final active scaffold or is used to fine-tune activity and ADME properties |
Agrochemicals and plant protection | Atrazine, chloropyridine intermediates | Serves as the active pesticide itself or as a key precursor to insecticides / herbicides |
Synthetic chemistry and library construction | 2,4-Dichloropyrimidine, chloropyridines, cyanuric chloride | Acts as a building block for nucleophilic substitution, cross-coupling, and stepwise introduction of substituents |
Polymers and functional materials | Triazine polymers and triazine functional materials derived from cyanuric chloride | Serves as a three-armed linking core, sequence-definable scaffold, electron acceptor, or functional unit |
Methodology development and late-stage modification | Heteroaryl chlorides obtained by late-stage chlorination of amino heterocycles | Provides a "late-stage transformable site" for complex scaffolds |
V. Four Typical Roles of Organic Chlorinated Heterocyclic Compounds in Research
Role | Description | Typical Significance |
Final active scaffold | Chlorine remains in the final molecule and directly affects molecular recognition and properties | Used in the design of active molecules such as drugs, pesticides, and probes |
Further-buildable intermediate | Chlorine serves as a leaving group or coupling site | Makes it easy to rapidly generate a series of analogs |
Multifunctional linking core | Multiple chlorine sites are present on one scaffold and can be replaced stepwise | Suitable for constructing three-armed / multi-armed linkers, dendritic molecules, or sequence-controlled molecules |
Late-stage modification entry point | A chlorine site is introduced at a late stage on a complex molecule and then further transformed | Improves the efficiency of structure optimization and reduces the need to redesign the route from scratch |
Example 1: 2,4-Dichloropyrimidine - a typical "further-buildable" intermediate
Substrates such as 2,4-dichloropyrimidine are common not because they are final targets in themselves, but because they allow researchers to replace chlorine atoms at different positions in a planned manner in subsequent steps and rapidly obtain a series of nitrogen-containing heterocyclic analogs. More importantly, they are not simply "equivalents of two identical chlorines." The literature shows that reactions of 2,4-dihalopyrimidines usually favor C4, while recent work has developed unconventional C2-selective coupling conditions. For experimental designers, this means that an organic chlorinated heterocycle is often not just a "chlorinated ring," but a scaffold that already contains information about site selectivity.
Example 2: Cyanuric chloride - a triazine linking core with multiple sites and stepwise controllability
Cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) is one of the most typical organic chlorinated heterocycles. It carries three chlorine sites that can be replaced step by step, so it is often used as a three-armed linking core, a branching platform, or a multifunctional molecular assembly node. Relevant studies and reviews show that the three chlorines of cyanuric chloride can be functionalized stepwise through sequential, controlled nucleophilic substitutions. A common practical pattern is that the first substitution is controlled at low temperature, the second can proceed at room temperature, and the third often requires a higher temperature; different nucleophiles also show different preferences for installation order. Because of this "stepwise" and "programmable" character, it is widely used to construct dendritic molecules, sequence-defined polymers, and multifunctional triazine materials.
Example 3: Chloropyridines - high-frequency members among agrochemical intermediates
In agrochemistry, organic chlorinated heterocycles often do not appear as the "final product," but rather as extremely important industrial intermediates. The literature points out that 2-chloro-5-methylpyridine is an important intermediate for the synthesis of neonicotinoid insecticides such as imidacloprid and acetamiprid. This shows that in many applications, the value of a chlorinated heterocycle does not lie in whether chlorine is retained in the final product, but in whether it provides the correct heterocyclic framework, the correct site reactivity, and a route entry point that can be scaled up industrially.
Example 4: Chloroquine and chlorpromazine - chlorine is not always a "temporary placeholder," but may be part of the final structure
Chloroquine is a 7-chloroquinoline antimalarial, while chlorpromazine is a chlorinated phenothiazine antipsychotic. They illustrate an important fact: in organic chlorinated heterocycles, chlorine is not always reserved for later replacement; sometimes it remains in the final drug structure all the way to the end. From the perspective of medicinal chemistry, chlorine is often used to tune hydrophobicity, electronic properties, metabolic stability, and potential halogen-bond interactions. Accordingly, it may function either as a "reaction site" or as a "property-design site."
VI. When Is It Worth Prioritizing Organic Chlorinated Heterocyclic Compounds
Research Goal / Experimental Need | Why Consider Organic Chlorinated Heterocycles |
Need to rapidly prepare a set of structural analogs | A chlorine site often serves as an entry point for nucleophilic substitution or coupling, making it convenient to build a small structural library |
Need to fine-tune activity and properties without drastically changing the scaffold | Chlorine is often used to fine-tune the electronic environment, hydrophobicity, and steric occupancy |
Need a multi-site linking core | Scaffolds such as polychlorinated triazines are suitable for stepwise assembly of different fragments |
The target molecule itself comes from a scaffold commonly found in drugs or agrochemicals | Chlorinated heterocycles already have many successful precedents in pharmaceuticals and agrochemicals |
Need late-stage modification of a complex molecule | Heteroaryl chlorides are often well suited as sites for late-stage derivatization |
VII. Common Points to Note When Using Organic Chlorinated Heterocyclic Compounds
Point to Note | Why It Matters |
Do not treat all chlorinated heterocycles as the same type of substrate | Scaffolds such as pyridine, pyrimidine, triazine, quinoline, and thiazine differ greatly in electronic properties and site reactivity |
Do not assume that "chlorine-containing" automatically means "easy to react" | Many aryl chlorides / heteroaryl chlorides are less reactive than bromides or iodides in coupling reactions and often require stronger catalytic systems |
For polychlorinated substrates, site selectivity must be judged first | Multiple chlorine sites in the same molecule may have a clear reaction order, so route design cannot rely on assumptions |
In medicinal chemistry optimization, do not look only at improved activity | Chlorine substitution often changes lipophilicity, solubility, and metabolic properties at the same time; this can be beneficial, but it can also be detrimental |
For multifunctional linking substrates, control temperature and sequence | For example, cyanuric chloride often relies on temperature and the order of nucleophile addition to achieve stepwise substitution |
Safety and environmental considerations must be checked compound by compound | Some low-molecular-weight chlorinated heterocycles can pose irritation or acute-toxicity risks and should not be handled in an overly general way |
In addition, two further points deserve attention.
1. "Synthetic utility" and "final-molecule design" are not the same thing. A given chlorine site may be very suitable for substitution, coupling, or late-stage derivatization, but whether it should be retained in the final molecule must still be judged comprehensively in light of the target activity, selectivity, solubility, lipophilicity, metabolic stability, and safety.
2. Do not automatically equate "chlorine-containing" with "higher hazard" or "higher biological activity." What truly determines performance is the complete structure, the biological target, the dose, the route of exposure, the exposure level, the metabolic process, and the specific use scenario; each compound must be assessed individually.
VIII. Product Navigation for Organic Chlorinated Heterocyclic Compounds: Quickly Locate Tables 1–4 by Research Task
Research Task / Experimental Need | Product Types to Focus On | Which Table to Consult First | Navigation Note |
Triazine herbicide residue analysis, environmental monitoring, analytical standard preparation, or method validation | Known agroactive compounds such as atrazine and simazine | Table 1 | Table 1 concentrates known active molecules and agroactive compounds, making it suitable for analytical standards, residue detection, reference studies, and recognition of active triazine scaffolds. |
Pharmaceutical analysis, pharmacological study, mechanistic validation, or reference experiments using known chlorinated heterocyclic drugs | Representative drugs such as chloroquine, chlorpromazine, and chlorzoxazone | Table 1 | If the goal is to directly use classic drug molecules for analysis, controls, or mechanistic studies, Table 1 is the most direct choice because it contains final active molecules rather than general intermediates. |
Design of quinoline antimalarial scaffolds or 4-aminoquinoline routes | 4,7-Dichloroquinoline and related quinoline active molecules | Table 1 | Table 1 includes both chloroquine and its key precursor 4,7-dichloroquinoline, making it well suited for understanding the research uses of quinoline chlorinated heterocycles from the integrated perspective of "final product - precursor." |
Need a triazine platform for sequential substitution in multi-arm linking, materials modification, dye modification, or multifunctional assembly | Cyanuric chloride, 2-chloro-4,6-dimethoxy-1,3,5-triazine | Table 2 | The triazine entries in Table 2 are more oriented toward linking platforms and coupling-activation reagents, and are therefore suitable for molecular assembly, carboxylic acid activation, material grafting, and sequence-defined construction. |
Screening pyrimidine medicinal chemistry intermediates, SNAr substitution, stepwise functionalization, or building polysubstituted pyrimidine scaffolds | 2-Chloropyrimidine, 2,4-dichloropyrimidine, 4,6-dichloropyrimidine, trichloropyrimidine, and their amino derivatives | Table 2 | Table 2 is the most concentrated table for pyrimidines and is suitable for substitution reactions of electron-deficient nitrogen heterocycles, lead expansion, and route design for polysubstituted pyrimidines. |
Construction of quinazoline scaffolds, kinase-inhibitor-related scaffolds, or medicinal chemistry optimization of fused nitrogen heterocycles | 2,4-Dichloroquinazoline | Table 2 | Although quinazoline is represented by only one entry, its application direction is very clear; if the target is the construction of a classic medicinal chemistry scaffold, Table 2 is the better match. |
Design of 7-deazapurine, nucleoside analog, purine-mimetic scaffold, or enzyme / receptor inhibitor precursors | 6-Chloro-7-deazapurine, 2,6-dichloro-7-deazapurine | Table 2 | Table 2 contains these distinctive intermediates that are more closely related to medicinal chemistry and nucleoside-analog routes, and is suitable for structural extension of fused nitrogen heterocycles and nucleoside mimetics. |
Need the most basic and most commonly used chloropyridine building blocks for pyridine substitution, coupling, or the synthesis of pesticide / drug intermediates | 2-Chloropyridine, 3-chloropyridine, and 2,3- / 2,4- / 2,5- / 2,6-dichloropyridines | Table 3 | Table 3 concentrates the basic pyridine-series building blocks and is best suited to route design that starts with assembly of a pyridine scaffold and then proceeds through stepwise modification. |
Development of medicinal chemistry precursors based on amino chloropyridines, pyrazines, pyridazines, and other electron-deficient nitrogen heterocycles | 5-Amino-2-chloropyridine, 2-amino-4,6-dichloropyridine, 2-chloropyrazine, 2,6-dichloropyrazine, 3,5- / 3,6-dichloropyridazine | Table 3 | Table 3 is better suited to research needs centered on medicinal chemistry intermediates and electron-deficient six-membered nitrogen heterocycles, especially for site-selective substitution and structural diversification. |
Research on pyridinecarboxylic-acid-type pesticide intermediates or herbicide-related compounds | 2-Chloronicotinic acid, clopyralid, 4-amino-3,6-dichloropicolinic acid | Table 3 | Table 3 includes not only basic pyridine building blocks but also pyridinecarboxylic-acid agrochemical intermediates and active compounds, making it suitable for agrochemical route design and structure-activity relationship analysis. |
Derivatization of benzothiazole, benzoxazole, or benzimidazole scaffolds, or development of heterocyclic ligands / functional molecules | 2-Chlorobenzothiazole, 2-chlorobenzoxazole, 2-chlorobenzimidazole | Table 4 | Table 4 focuses on benzo-fused chlorinated heterocyclic intermediates and is suitable for fused-scaffold modification, derivatization of active molecules, and functional molecule design. |
Thiazole agrochemical / medicinal chemistry intermediates, condensation reactions, reductive amination, or assembly of small functionalized molecules | 2-Chlorothiazole, 2-chloro-1,3-thiazole-5-carboxaldehyde | Table 4 | The thiazole entries in Table 4 balance basic building blocks and functionalized intermediates and are especially suitable for routes that need to use a "chlorine site + aldehyde site" in a coordinated way. |
Table 1 | Representative Active Molecules, Agroactive Compounds, and Key Drug Precursors
Category | CAS No. | Aladdin Cat. No. | Name | Spec. / Purity | Product Features / Applications |
Chlorinated triazine herbicide | 1912-24-9 | Atrazine | Analytical standard | A classic chlorinated triazine herbicide standard, suitable for herbicide residue analysis, environmental monitoring, and method validation, and also useful as a reference compound for research on triazine active scaffolds. | |
Chlorinated triazine herbicide | 122-34-9 | Simazine | ≥96% | A classic chlorinated triazine herbicide suitable for residue analysis, environmental sample testing, method validation, and research on triazine activity. | |
Chlorinated pyridinecarboxylic acid herbicide | 1702-17-6 | Clopyralid | ≥96% | An active pyridinecarboxylic acid herbicide that can be used for residue analysis, environmental monitoring, method development, and herbicide mechanism studies. | |
Chlorinated pyridinecarboxylic acid herbicide | 150114-71-9 | 4-Amino-3,6-dichloropicolinic acid | ≥97% | An active chlorinated pyridinecarboxylic acid herbicide molecule that can be used for herbicidal activity studies, as a standard / reference compound, and for structure-activity relationship analysis of this scaffold type. | |
Chlorinated benzoxazole active molecule | 61-80-3 | 2-Amino-5-chlorobenzoxazole | Moligand™, ≥99% | A chlorinated benzoxazole active scaffold that can be used in pharmacological active-molecule screening and structure-activity relationship studies, and also serves as a chlorinated heterocyclic template for further derivatization. | |
Chlorinated benzoxazole drug | 95-25-0 | Chlorzoxazone | Moligand™, ≥98% | A classic chlorinated benzoxazole drug that can be used for pharmaceutical analysis, metabolism studies, pharmacological controls, and related method development. | |
Chlorinated quinoline drug | 54-05-7 | Chloroquine | Moligand™, ≥97% | A classic chlorinated quinoline antimalarial drug that can be used for pharmaceutical analysis, mechanism-of-action studies, cell or parasite research controls, and as a reference for quinoline scaffold optimization. | |
Chlorinated phenothiazine drug | 50-53-3 | Chlorpromazine | Moligand™, ≥95% | A classic chlorinated phenothiazine drug that can be used for pharmaceutical analysis, neuropharmacology studies, receptor / ion channel experiments, and as a reference for phenothiazine scaffold research. | |
Chlorinated quinoline drug intermediate | 86-98-6 | 4,7-Dichloroquinoline | ≥98%(GC) | A key intermediate for chloroquine and other 4-aminoquinoline molecules, and also commonly used for constructing quinoline-based anti-infective / antimalarial scaffolds. |
Table 2 | Triazine-, Pyrimidine-, Quinazoline-, and 7-Deazapurine-Type Nitrogen Heterocycle Intermediates
Category | CAS No. | Aladdin Cat. No. | Name | Spec. / Purity | Product Features / Applications |
Chlorinated triazine linking platform | 108-77-0 | Cyanuric chloride | ≥99% | A classic trichlorotriazine linking platform whose three chlorine sites can be substituted stepwise; commonly used in the synthesis of multi-arm molecules, dye / material modification, and agrochemical or medicinal intermediates. | |
Chlorinated triazine coupling reagent | 3140-73-6 | 2-Chloro-4,6-dimethoxy-1,3,5-triazine | ≥97% | A stable and efficient triazine coupling reagent commonly used for amide-bond formation, peptide / small-molecule coupling, and activation of carboxylic acid substrates. | |
Basic chloropyrimidine building block | 1722-12-9 | 2-Chloropyrimidine | ≥99%(GC) | A basic chloropyrimidine building block suitable for SNAr substitution and further functionalization; a common starting material for the synthesis of nucleoside analogs, medicinal heterocycles, and functional molecules. | |
Polychloropyrimidine activated intermediate | 3764-01-0 | 2,4,6-Trichloropyrimidine | ≥98% | A highly reactive polychloropyrimidine intermediate suitable for sequential SNAr substitution and commonly used for rapidly building polysubstituted pyrimidine medicinal scaffolds. | |
Dichloropyrimidine core intermediate | 3934-20-1 | 2,4-Dichloropyrimidine | ≥98% | A classic dichloropyrimidine platform commonly used for regioselective SNAr, cross-coupling, and the synthesis of polysubstituted pyrimidine libraries. | |
Dichloropyrimidine core intermediate | 1193-21-1 | 4,6-Dichloropyrimidine | ≥98% | A classic dichloropyrimidine intermediate commonly used for stepwise substitution at the 4- and 6-positions to construct polysubstituted pyrimidine scaffolds such as kinase inhibitors. | |
Amino chloropyrimidine medicinal chemistry intermediate | 56-05-3 | 2-Amino-4,6-dichloropyrimidine | ≥98% | An amino dichloropyrimidine intermediate that retains sites for further substitution and facilitates the introduction of hydrogen-bond-recognition units; commonly used in purine / pyrimidine medicinal chemistry optimization. | |
Amino chloropyrimidine medicinal chemistry intermediate | 5177-27-5 | 5-Amino-2,4-dichloropyrimidine | ≥97% | An amino dichloropyrimidine intermediate used in the synthesis of polysubstituted pyrimidines and fused nitrogen heterocycles; a common precursor in medicinal chemistry and nucleoside-analog routes. | |
Amino chloropyrimidine medicinal chemistry intermediate | 156-83-2 | 2,4-Diamino-6-chloropyrimidine | ≥98% | An amino chloropyrimidine intermediate commonly used as a precursor for building purines and fused nitrogen heterocycles, and for the synthesis of nucleoside analogs and medicinal molecules. | |
7-Deazapurine chlorinated medicinal chemistry intermediate | 3680-69-1 | 6-Chloro-7-deazapurine | ≥98% | A 7-deazapurine chlorinated intermediate used for further modification of nucleoside analogs, receptor / enzyme inhibitors, and purine-mimetic scaffolds. | |
7-Deazapurine chlorinated medicinal chemistry intermediate | 90213-66-4 | 2,6-Dichloro-7-deazapurine | ≥98%(HPLC) | A dichloro 7-deazapurine intermediate suitable for site-selective substitution and coupling; used in the construction of nucleoside analogs, kinase inhibitors, and purine-mimetic scaffolds. | |
Chlorinated quinazoline medicinal chemistry intermediate | 607-68-1 | 2,4-Dichloroquinazoline | ≥95% | A highly reactive chlorinated quinazoline intermediate commonly used in the synthesis of medicinal scaffolds such as 4-anilinoquinazolines; a classic building block in kinase-inhibitor routes. |
Table 3 | Pyridine, Pyrazine, Pyridazine, and Pyridinecarboxylic Acid Building Blocks and Medicinal Chemistry Intermediates
Category | CAS No. | Aladdin Cat. No. | Name | Spec. / Purity | Product Features / Applications |
Basic chloropyridine building block | 109-09-1 | C474470 | 2-Chloropyridine | 99% | A basic chloropyridine building block commonly used for nucleophilic substitution, cross-coupling, and the introduction of nitrogen-heterocycle fragments; a common intermediate in medicinal and agrochemical synthesis. |
Basic chloropyridine building block | 626-60-8 | 3-Chloropyridine | ≥99% | A basic chloropyridine building block commonly used in the synthesis of pesticide and pharmaceutical intermediates and for further functionalization of pyridine scaffolds. | |
Dichloropyridine basic building block | 2402-77-9 | 2,3-Dichloropyridine | ≥99% | A chloropyridine with two leaving-group sites, suitable for stepwise substitution and diversified library synthesis, and useful for rapid modification of pyridine scaffolds in agrochemistry and medicinal chemistry. | |
Dichloropyridine basic building block | 26452-80-2 | 2,4-Dichloropyridine | ≥98%(GC) | A dichloropyridine building block suitable for stepwise SNAr or coupling, commonly used to construct substituted pyridine libraries and pesticide / drug intermediates. | |
Dichloropyridine basic building block | 16110-09-1 | 2,5-Dichloropyridine | ≥99% | A dichloropyridine building block suitable for site-differentiated substitution and coupling, commonly used to construct polysubstituted pyridine intermediates and active-molecule scaffolds. | |
Dichloropyridine basic building block | 2402-78-0 | 2,6-Dichloropyridine | ≥97% | A dichloropyridine building block commonly used for stepwise substitution to obtain 2,6-difunctionalized pyridine derivatives; a common intermediate in medicinal and agrochemical chemistry. | |
Agrochemical-intermediate-type chloropyridine | 18368-64-4 | 2-Chloro-5-methylpyridine | ≥97% | A classic chloropyridine of the agrochemical-intermediate type, commonly used in the synthesis of agroactive molecules and also useful for constructing substituted pyridine ligands and heterocyclic intermediates. | |
Amino chloropyridine medicinal chemistry intermediate | 5350-93-6 | 5-Amino-2-chloropyridine | ≥98% | An amino chloropyridine intermediate commonly used for constructing pyridine fragments in drug leads and agrochemical molecules, and also convenient for further acylation, coupling, or substitution. | |
Amino chloropyridine medicinal chemistry intermediate | 116632-24-7 | 2-Amino-4,6-dichloropyridine | ≥97% | An amino dichloropyridine intermediate suitable for building polysubstituted aminopyridine medicinal scaffolds and for further SNAr and coupling derivatization. | |
Amino chloropyridine medicinal chemistry intermediate | 2587-02-2 | 4-Amino-2,6-dichloropyridine | ≥97% | An amino dichloropyridine intermediate suitable for building polysubstituted aminopyridine lead molecules while retaining room for subsequent site-selective substitution. | |
Pyridinecarboxylic acid agrochemical intermediate | 2942-59-8 | 2-Chloronicotinic acid | ≥98% | A chlorinated pyridinecarboxylic acid intermediate that contains both a carboxylic-acid transformation site and a chlorinated site; commonly used in the construction of agrochemicals, medicinal molecules, and ligands. | |
Chloropyrazine building block | 14508-49-7 | 2-Chloropyrazine | ≥98% | A basic chloropyrazine building block commonly used in SNAr substitution, coupling, and medicinal scaffold extension of electron-deficient heterocycles. | |
Dichloropyrazine basic building block | 4774-14-5 | 2,6-Dichloropyrazine | ≥98% | A dichloropyrazine intermediate suitable for sequential substitution to build electron-deficient pyrazine scaffolds, and commonly used in medicinal chemistry and functional heterocycle development. | |
Dichloropyridazine basic building block | 1837-55-4 | 3,5-Dichloropyridazine | ≥98% | A dichloropyridazine building block suitable for site-differentiated substitution and diversified synthesis of pyridazine scaffolds. | |
Dichloropyridazine basic building block | 141-30-0 | 3,6-Dichloropyridazine | ≥98%(GC) | A dichloropyridazine building block that facilitates sequential substitution to construct polysubstituted pyridazine derivatives; common in medicinal leads and heterocyclic methodology research. |
Table 4 | Benzo-Fused Heterocyclic and Thiazole Chlorinated Intermediates
Category | CAS No. | Aladdin Cat. No. | Name | Spec. / Purity | Product Features / Applications |
Chlorinated benzothiazole intermediate | 615-20-3 | 2-Chlorobenzothiazole | ≥98%(GC) | A chlorinated benzothiazole intermediate used for further derivatization in medicinal chemistry, fluorescent / materials molecules, and functional heterocycles. | |
Chlorinated benzoxazole intermediate | 615-18-9 | 2-Chlorobenzoxazole | ≥98%(GC) | A chlorinated benzoxazole intermediate suitable for constructing benzoxazole active molecules, ligands, and functional material derivatives. | |
Chlorinated benzimidazole intermediate | 4857-06-1 | 2-Chlorobenzimidazole | ≥97% | A chlorinated benzimidazole intermediate commonly used in medicinally active scaffolds, coordination / functional molecules, and further N- or C-site modification. | |
Basic chlorothiazole building block | 3034-52-4 | 2-Chlorothiazole | ≥98% | A basic chlorothiazole building block used to construct thiazole fragments in agrochemicals, drugs, and functional materials. | |
Functionalized chlorothiazole intermediate | 95453-58-0 | 2-Chlorothiazole-5-carboxaldehyde | ≥97% | A functionalized chlorothiazole intermediate bearing both an aldehyde group and a chlorine site; suitable for condensation, reductive amination, and further substitution, and a common fragment in agrochemical and medicinal chemistry. |
Note: The products listed 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 "product name / CAS / catalog number".
For more related articles, see below:
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