1.Benzothiophene: One Scaffold Connecting Three Main Lines—“Materials → Synthetic Building Blocks → Sulfur Transformations”
Benzothiophene (benzo[b]thiophene) draws sustained attention because it is one of the most widely used “engineerable fragments” among fused aromatic sulfur heterocycles. It can be expanded upward into larger fused systems that frequently appear in organic electronic materials (e.g., BDT, BTBT), and it can also serve downward as a modular heteroaryl unit for method development and derivatization in pharmaceuticals/ligand design. Its core value can be summarized into three lines: scaffold scalability, site selectivity, and switchable sulfur oxidation state.
Main line | Key capability provided by the benzothiophene scaffold | Why this line is commonly used |
Materials: conjugated/semiconducting systems (OPV/OFET/OLED, etc.) | Expandable fused, planar π scaffold (fused sulfur-hetero platforms such as benzothiophene / BDT / BTBT; branched by application) | Planarity and packability are core variables governing charge transport and morphology windows in devices; BDT/BTBT are mature “platform scaffolds.” |
Synthesis: modular assembly and structural diversification | Divergent design at the 2/3 positions; comprehensive entry points via halogenation/boronic acids (esters)/other functional handles | Cross-coupling and functional-group interconversion allow “scaffold assembly” and “end-group tuning” to be separated, improving route transferability. |
Sulfur transformations: oxidation/desulfurization/polarity increase and mechanistic benchmarking | The sulfur center can be switched from sulfide to more polar sulfone/dioxide forms | Oxidation to sulfones/sulfoxides often markedly increases polarity, facilitating extraction/adsorptive separations and enabling mechanistic comparisons. |
2.What Is Benzothiophene?
2.1 Definition and Basic Information
Benzothiophene (benzothiophene; the systematic fused name is often written as benzo[b]thiophene) is a fused aromatic heterocycle formed when a benzene ring and a thiophene ring share two adjacent atoms and a bond. Its molecular formula is C₈H₆S, and a common synonym is thianaphthene.
2.2 What Does the [b] in “benzo[b]…” Mean?
1. In IUPAC fused-ring nomenclature, fusion refers to combining two rings such that each contributes one bond, thereby forming a shared bond (and the two rings consequently share that bond and its two terminal atoms).
2. When a benzene ring is fused to a heterocycle, one must specify which edge (which bond) of the heterocycle is involved in the fusion. This is the role of the bracketed letters [a], [b], [c]…: they indicate “which edge of the heteroring is fused.”
3. Taking thiophene as an example: first, thiophene is numbered according to the rules (the heteroatom position is prioritized, and the direction is determined by the fusion position), and then letters are used to label the fused edge. The [b] in benzo[b]thiophene means “the benzene ring is fused to the b edge of the thiophene ring.” Different fusion edges lead to different structural isomers (e.g., benzo[b]thiophene vs benzo[c]thiophene). Although they share the same molecular formula (C₈H₆S), the numbering, functionalizable positions, and synthetic routes differ accordingly. For thiophene (with S at position 1), ring edges are commonly labeled as a = 1–2, b = 2–3, c = 3–4, …; therefore, benzo[b]thiophene denotes fusion at the thiophene 2–3 bond (the b edge).
3.A “Small-to-Large” Scaffold Map of the Benzothiophene Family
Scaffold level | Representative structure | Structural features | Typical uses (corresponding product tables below) |
Parent core | Benzothiophene (benzothiophene) | The smallest benzene–thiophene fused aromatic sulfur heterocycle; can serve as a “general fragment/benchmark substrate” | Building blocks and functionalization entry points: Table 3 / Table 4 |
Larger fused sulfur aromatics | Dibenzothiophene (DBT) | Larger π surface; often used as a model substrate for sulfur-containing aromatics | Oxidation/desulfurization and mechanistic benchmarking: Table 3 / Table 4 |
Donor platform for materials | Benzodithiophene (BDT) | Symmetric positions + clearly defined side-chain positions; convenient for building D–A conjugated systems | Conjugated polymer/small-molecule monomers: Table 1 |
High-crystallinity device scaffold | Larger fused systems such as BTBT | Strong advantages in planarity and packing; device performance is sensitive to purity/morphology | OFET/transport/sublimation purification: Table 2 |
Oxidation-state derivatives | Sulfones/dioxides (S → SO₂) | Polarity/electronic properties change substantially; useful for acceptor design or mechanistic controls | Oxidation controls/acceptor conversion: Table 4 |
4.Structural Features: Three “Knobs” That Turn Benzothiophene from a “Structure” into a Practical Tool
Benzothiophene spans materials, synthetic building blocks, and sulfur transformations because of three knobs:
(1) Scaffold size (fused-ring extension)
(2) Site topology (divergence at the 2/3 positions)
(3) Sulfur oxidation state (S → SOx)
They answer, respectively: What changes when you make the scaffold larger? Where is it most straightforward to modify? How can the same scaffold be used for property/mechanistic benchmarking?
Knob | What changes | Takeaway | Common scenarios |
Scaffold size (fused-ring extension) | π-surface size/rigidity/planarity | The larger it is, the more “materials-like”: packing, morphology, and sensitivity to purity/regioisomers increase; the smaller it is, the more “building-block-like”: better as a general fragment and benchmark substrate | Platform scaffolds for materials vs method/benchmark substrates |
Site topology (2/3-position divergence) | Whether substitution proceeds at C2 (α) or C3 (β) | C2 is more like a “handle for modular assembly” (often more amenable to workflow-style coupling/capture); C3 is more like a “fast route to an alternative topology” (more direct for site benchmarking/diversification) | Route planning and building-block library construction (prepare C2 and C3 series separately) |
Sulfur oxidation state (S → SO / SO₂) | Polarity and electronic effects | Oxidation usually increases polarity substantially, aiding extraction/adsorptive separation and making the scaffold more electron-withdrawing; sulfoxides are often “possible intermediates but not necessarily easy to isolate” | Oxidative desulfurization/separation, property/mechanistic benchmarking, acceptor conversion validation |
5.Application Landscape: Three High-Frequency Scenarios
Although the benzothiophene family may appear scattered across fields, the underlying logic consistently centers on controllable variables: on the materials side, focus on “fused platform + side-chain engineering”; on the synthesis side, focus on “fix 2/3 topology first, then choose coupling tools”; on the desulfurization/benchmarking side, focus on “polarity jumps driven by S → SOx.”
5.1 Scenario 1: Organic Electronic Materials (Conjugated/Semiconducting)
5.1.1 Core variables: fused platform + substitution/side-chain engineering.
In materials systems, the value of the benzothiophene family is not simply “whether it can be functionalized,” but rather: by systematically varying fused-ring size and side chains/substituents on a common platform, differences can be reproducibly mapped to energy levels, packing, and thin-film morphology—thereby influencing device performance and consistency.
1. BDT-type platforms: commonly used as donor units in D–A conjugated systems. Their advantage lies in clear substitution positions, which facilitates systematic comparisons of side chains and substituents to establish structure–property relationships.
2. BTBT-type platforms: often used as molecular semiconductor platforms for transistors. They are characterized by higher sensitivity to crystallization/packing and processing windows, making them suitable for studying morphology–process–performance coupling.
Summary: On the materials side, the most common “tuning knobs” are twofold—select the right fused platform first, then use side chains/substituents to tune solubility, film formation, and crystalline domain formation. Oxidation state is more often used for controls/mechanistic design, rather than as a routine mainline tuning method.
5.2 Scenario 2: Modular Synthesis and Method Development (Structural Diversification)
5.2.1 Core variable: choose topology first (C2 or C3), then choose the assembly tool.
When making a series of benzothiophene derivatives, the most cost-effective approach is not to start by choosing reaction conditions, but to first decide the desired substitution topology. A C2 route and a C3 route naturally steer downstream structures in different directions. Once the site is fixed, coupling/capture/functional-group interconversion becomes a matter of tool selection.
5.2.2 A two-step routing logic for modular synthesis: fix 2/3 topology first, then choose the bond-forming mode
Step 1: desired substitution topology | Step 2: most commonly used bond-forming mode | Common output form |
C2 route (α) | Coupling-based assembly (Suzuki/Negishi/Sonogashira, etc.) or metallation followed by electrophile capture | C2-substituted derivatives; more like a “stable, controllable coupling entry point,” convenient for telescoping/sequence-building |
C3 route (β) | More commonly: first obtain pre-functionalized building blocks such as 3-halides or 3-boronic acids (esters) (or convert via metallation), then proceed to coupling/capture | C3-substituted derivatives; more like “rapid access to an alternative topology,” used to quickly establish a topology distinct from C2 for site benchmarking or diversification |
5.3 Scenario 3: Oxidation/Desulfurization of Sulfur-Containing Aromatics and Mechanistic Benchmarking (Polarity Increase)
5.3.1 Core variable: S → SOx converts sulfides into more polar oxidized forms.
In oxidative desulfurization and separation-related research, benzothiophene/dibenzothiophene are frequently used as representative substrates. A recurring logic is: oxidation increases polarity, making these species easier to remove from organic matrices via extraction, adsorption, and related methods; meanwhile, switching oxidation state provides a “same scaffold, directly comparable” axis for mechanistic benchmarking.
5.3.2 Two most common benchmarking strategies: compare oxidation state, or compare scaffold size
Benchmark axis | What is being compared | Questions it typically answers |
Same scaffold: sulfide vs sulfone | Structure held constant; only oxidation state changes | How polarity changes affect extraction/adsorption/phase behavior; how electronic effects changes affect reactivity |
Different scaffolds: benzothiophene vs dibenzothiophene | Different fused-ring size | How fused-ring size/electron-density differences affect oxidation rate and separation difficulty (substrate benchmarking) |
6.Product Navigation Table｜Benzothiophene-Related Chemicals: Quickly Locate by Research Task (Corresponding to Tables 1–4)
Research / experimental need | Which table to check first | Rationale for table choice | Representative products in the table |
Build “monomers” for conjugated polymers / small-molecule materials: BDT donor-core systems (OPV/OFET/OLED), requiring halogenation/stannylation/diketone “polymerization sites” and side-chain solubility tuning | Table 1 (BDT platform monomers) | Table 1 concentrates the core monomer forms of BDT (benzodithiophene): 2,6-dihalo (Suzuki/Stille handles), 2,6-bis(stannyl) (Stille monomers), 4,8-side-chain solubility tuning, and 4,8-dione acceptor conversion; this most directly matches selection points for “materials synthetic routes and reproducible scale-up.” | 2,6-dibromo BDT (D155654); 2,6-bis(stannyl) BDT (B475037); 4,8-alkoxy-substituted BDT (B152917/D290569); 2,6-dibromo-4,8-dione (D1503538) |
High-mobility fused small molecules / device-grade purification: BTBT systems (OFET) or larger fused sulfur heteroaromatic scaffolds; focus on crystallinity, thin-film morphology, sublimation purification, and device consistency | Table 2 (BTBT / larger fused scaffolds) | Table 2 focuses on the BTBT fused core and larger fused systems: the key determinants of carrier transport are the planarity and packing of the fused scaffold; alkyl/aryl substitution and “sublimation purification” map directly to the purity–morphology window required in device studies. | BTBT (for organic electronics, H404586); 2,7-dioctyl BTBT (D304058); 2-bromo BTBT (B405464); 2,7-diphenyl BTBT (sublimed, D404593); larger fused scaffold (B405287) |
Cross-coupling for methodology or structural diversification: need benzothiophene halide / boronic acid (ester) building blocks (Suzuki/Negishi/Sonogashira, etc.) to rapidly stitch aryl/heteroaryl/acceptor fragments | Table 4 (cross-coupling building blocks + oxides) | Table 4 consolidates building blocks that can go directly into coupling: halides (Cl/Br/I) for oxidative addition, boronic acids/esters for Suzuki; it also includes sulfones/dioxides as electronic-property controls/acceptor conversion motifs or oxidation-mechanism controls—useful for route and condition screening. | 2-bromo (B185084) / 3-bromo (B189193); 2-iodo (I169943) / 3-iodo (I725545); 2,3-dibromo (D405726); 2-pinacol boronate (B303598) / 3-pinacol boronate (B405356); boronic acids (B103172/B290885); dibenzothiophene sulfone (D101955) |
You already have the “benzothiophene scaffold” and need fast functional-group transformations: condensations/bond formation, linker installation, polarity/acceptor tuning (aldehyde/acid/ester/nitrile/acetic-acid side chain) for material end groups, probes, drug leads, or ligand derivatization | Table 3 (functional intermediates) | Table 3 provides the most “directly transformable” functional entries: aldehydes for Knoevenagel/Wittig/reductive amination, acids/esters for amidation and linker installation, nitriles for acceptor end groups and downstream conversions—ideal for end-group construction, linker introduction, and property tuning. | 2-carbaldehyde (B123079) / 3-carbaldehyde (B152938); 2-carboxylic acid (B152934) / 3-carboxylic acid (B123049); 2-methyl ester (M168796); 2-cyano (B193892) / 3-acetonitrile (B168969); 3-acetic acid (B179488); parent benzothiophene (B107023) |
Benchmarking/mechanistic studies on “oxidation/desulfurization/polarity increase” of sulfur aromatics: compare sulfide vs sulfone/dioxide and their impacts on reactivity and properties | Table 4 (oxides in the same table) + Table 3 / Table 1 (supplement by scaffold) | Sulfones/dioxides best capture post-oxidation changes in electronics and polarity; if your study requires comparing different scaffolds (benzothiophene/dibenzothiophene/BDT), revisit Table 3 (parent cores) or Table 1 (BDT diones/substituted forms) to complete the comparison set. | Dibenzothiophene sulfone (D101955); benzothiophene 1,1-dioxide (T304728); dibenzothiophene (D106395); BDT dione (B119991/D1503538) |
You have a target scaffold but are unsure which “starting material class” is the most robust: build the minimal reagent set for a reproducible route (parent / halide / boronate / functional entry points) | Table 4 first → then Table 3 (and, if needed, Table 1 / Table 2) | In practice, the most universal and transferable approach is modular assembly using “halides + boronic acids (esters)”; if end groups/linkers are needed, complete the set with aldehydes/acids/nitriles; if your target is a device/material main chain, return to the dedicated BDT/BTBT tables. | Table 4: B185084/B189193/I169943/B303598, etc.; Table 3: B123079/B152934/B193892, etc.; material main chains: Table 1 / Table 2 |
Usage suggestions:
For materials main chains, check Table 1 first; for fused semiconductor devices, check Table 2 first; for coupling building blocks/method development, check Table 4 first; for end groups and functional-group transformations, check Table 3 first.
Table 1｜Organic Electronics / Conjugated-Materials Monomers: BDT (Benzodithiophene) Platform (Halogenated/Stannylated/Dione and Side-Chain Variants)
Category | CAS No. | Aladdin Cat. No. | Name | Specification / Purity | Key features & applications |
Organic-electronics monomer | BDT stannylated (Stille coupling/polymerization monomer) | 1160823-78-8 | 2,6-Bis(trimethylstannyl)-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene | ≥99.5% (HPLC) | A 2,6-bis(stannyl) monomer of the BDT (benzodithiophene) donor core for rapidly building conjugated backbones via Stille coupling/polymerization; the 4,8-bis(2-ethylhexyloxy) side chains improve solubility and film formation, commonly used in OPV/OFET/OLED conjugated-polymer monomer systems. | |
Organic-electronics monomer | BDT halogenated (Suzuki/Stille polymerization monomer) | 1044795-06-3 | 2,6-Dibromo-4,8-bis(dodecyloxy)benzo[1,2-b; 4,5-b′]dithiophene | ≥98% (HPLC) | 2,6-Dibromo sites serve as cross-coupling “polymerization handles” on a BDT donor core; long-chain alkoxy substituents enhance solubility and film formation, commonly used for monomer construction of D–A conjugated polymers/small molecules (OPV/OFET) via Suzuki or Stille routes. | |
Organic-electronics monomer | BDT halogenated (Suzuki/Stille polymerization monomer) | 1294515-75-5 | 2,6-Dibromo-4,8-bis(n-octyloxy)benzo[1,2-b:4,5-b′]dithiophene | ≥98% (HPLC) | Also a BDT 2,6-dibromo monomer; n-octyloxy side chains balance solubility and crystallinity, often included in monomer libraries for solution-processable organic photovoltaic/transistor materials. | |
Organic-electronics monomer | BDT dibromo (key polymerization starting point) | 909280-97-3 | 2,6-Dibromobenzo[1,2-b:4,5-b′]dithiophene | ≥98% | A “basic” 2,6-dibromo BDT monomer and a common starting point for building BDT-based conjugated materials via Suzuki/Stille polymerization; used to quickly establish donor backbones for OPV/OFET systems. | |
Organic-electronics monomer | BDT halogenated (2,6-dibromo; solubility side chains) | 1226782-13-3 | 2,6-Dibromo-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene | ≥97% (HPLC) | 2,6-Dibromo provides polymerization handles, while 2-ethylhexyloxy side chains widen the solution-processing window; commonly used as a BDT-type conjugated-material monomer (Suzuki/Stille routes) for OPV/OFET device-material development. | |
Organic-electronics core | BDT parent core (donor fragment) | 267-65-2 | Benzo[1,2-b:4,5-b′]dithiophene | ≥98% | A classic fused donor unit widely used as a scaffold fragment in organic photovoltaics/transistors/emissive materials for structure–energy-level–morphology relationship studies. | |
Organic-electronics core | Alkoxy-substituted BDT (donor scaffold) | 1044795-04-1 | 4,8-Bis(dodecyloxy)benzo[1,2-b; 4,5-b′]dithiophene | ≥98% | A neutral BDT donor core with long-chain alkoxy substituents; commonly used in donor-fragment design and controls to improve solubility/film formation; can be combined with halide/boronic co-monomers to build D–A conjugated systems. | |
Organic-electronics core | Alkoxy-substituted BDT (donor scaffold) | 1098102-94-3 | 4,8-Di-n-octyloxybenzo[1,2-b:4,5-b′]dithiophene | ≥98% (GC) | A neutral BDT donor core (no halide/boron/tin): used for structure–performance controls (side-chain impacts on solubility, crystallization, and energy levels), and often serves as a parent fragment for subsequent halogenation/functionalization or conjugated-material design. | |
Organic-electronics core | Alkoxy-substituted BDT (donor scaffold) | 1160823-77-7 | 4,8-Bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene | ≥95% (HPLC) | A high-solubility BDT donor core (2-ethylhexyloxy side chains), commonly used in solution-processed OPV/OFET material design and controls (side-chain effects on energy levels/morphology/crystallinity). | |
Organic-electronics monomer | BDT stannylated (extended conjugation, Stille route) | 1352642-37-5 | 4,8-Bis[5-(2-ethylhexyl)thiophen-2-yl]-2,6-bis(trimethylstannyl)benzo[1,2-b:4,5-b′]dithiophene | ≥98% (HPLC) | Thiophene side fragments on a BDT core extend conjugation and tune energy levels; the 2,6-bis(stannyl) handles enable Stille coupling/polymerization to build longer donor segments, commonly used in high-conjugation OPV/OFET polymer or small-molecule designs. | |
Organic-electronics fragment | BDT dione (acceptor conversion / energy-level tuning) | 32281-36-0 | Benzo[1,2-b:4,5-b′]dithiophene-4,8-dione | ≥98% | The 4,8-dione markedly increases electron-accepting character and polarity; used as an acceptor-converted fragment in D–A systems and provides reactive sites for subsequent condensations/additions to tune energy levels and absorption. | |
Organic-electronics monomer | BDT dione dibromo (acceptor conversion + polymerization handles) | 196491-93-7 | 2,6-Dibromobenzo[1,2-b:4,5-b′]dithiophene-4,8-dione | — | Combines 2,6-dibromo coupling sites with a 4,8-dione acceptor-converted core for constructing stronger D–A conjugated systems (polymers/small molecules), enabling systematic tuning of absorption and energy levels and enhancing acceptor character. |
Table 2｜Fused Organic-Semiconductor Scaffolds: BTBT and Larger Fused Sulfur Heteroaromatic Systems (OFET/Transport and Device-Grade Purification)
Category | CAS No. | Aladdin Cat. No. | Name | Specification / Purity | Key features & applications |
Organic semiconductor | BTBT derivative (organic-electronics small molecule) | 1781261-93-5 | 2-Hexyl-7-phenyl[1]benzothieno[3,2-b][1]benzothiophene [for organic electronics] | ≥99.5% (HPLC) | A BTBT (benzothienobenzothiophene) fused sulfur heteroaromatic small molecule known for high crystallinity and strong π–π stacking; alkyl/aryl substitution tunes solubility and crystal packing, commonly used in OFETs, carrier-transport studies, and thin-film morphology research. | |
Organic semiconductor | Alkyl-substituted BTBT (solution processing) | 583050-70-8 | 2,7-Dioctyl[1]benzothieno[3,2-b][1]benzothiophene | ≥98% | Dioctyl substitution improves solubility while maintaining the packing advantages of the fused core; commonly used for solution-processable OFETs and studies optimizing thin-film morphology and mobility. | |
Organic-electronics building block | Halogenated BTBT (entry for structural modification) | 1398397-58-4 | 2-Bromo[1]benzothieno[3,2-b][1]benzothiophene | ≥95% | A halogenated BTBT fused core used for late-stage coupling modifications (introducing aryl/alkyl/acceptor fragments) to optimize packing and device performance; common in OFET material development. | |
Organic semiconductor | Aryl-substituted BTBT (device-grade purification) | 900806-58-8 | 2,7-Diphenyl[1]benzothieno[3,2-b][1]benzothiophene (sublimation purified) | — | Diphenyl-substituted BTBT with high conjugation and strong crystallization tendency; often used for OFET/single-crystal or thin-film transport studies; “sublimation purified” aligns with device requirements for trace-impurity control and electrical consistency. | |
Organic semiconductor | BTBT parent core (unsubstituted) | 248-70-4 | Benzo[b]benzo[4,5]thieno[2,3-d]thiophene | ≥97% | A polycyclic, highly planar fused scaffold favoring π stacking; used in high-mobility OFETs, and fused-scaffold studies for OLED/OPV as a structural benchmark. BTBT platform scaffold control/parent core. |
Table 3｜Benzo[b]thiophene Parent Cores and Directly Transformable Functional Intermediates (Aldehydes/Acids/Esters/Nitriles/Side-Chain Acids)
Category | CAS No. | Aladdin Cat. No. | Name | Specification / Purity | Key features & applications |
Base scaffold | Benzo[b]thiophene (parent) | 95-15-8 | Benzo[b]thiophene | ≥97% | Parent benzothiophene: a common hydrophobic aromatic sulfur heterocycle in medicinal chemistry; also a widely used fragment and benchmark substrate in organic semiconductors/conjugated materials and methodology studies. | |
Base scaffold | Dibenzothiophene (model/benchmark substrate) | 132-65-0 | Dibenzothiophene | ≥99% | A representative fused sulfur-containing aromatic often used as a model compound for oxidation/desulfurization, mechanistic and catalytic benchmarking; also serves as a building block scaffold in materials and medicinal chemistry. | |
Functional intermediate | Aldehyde (2-position) | 3541-37-5 | Benzo[b]thiophene-2-carbaldehyde | ≥98% (GC) | A high-throughput derivatization entry at C2: suitable for Wittig/Knoevenagel/reductive amination to connect benzothiophene to chromophores/acceptor end groups; used in OLED/OPV small molecules, drug leads, and ligand synthesis. | |
Functional intermediate | Aldehyde (3-position) | 5381-20-4 | Benzo[b]thiophene-3-carbaldehyde | ≥98% (GC) | C3 positioning enables a substitution map distinct from C2; also suitable for condensation/coupling derivatization to tune conjugation pathways and electronic effects (common intermediate in materials and medicinal chemistry). | |
Functional intermediate | Carboxylic acid (2-position) | 6314-28-9 | Benzo[b]thiophene-2-carboxylic acid | ≥98% (HPLC) (T) | A universal “connection point” at C2: enables esterification/amidation/coupling; often used to introduce anchoring groups (functional-material side chains, surface modification) or to build benzothiophene derivatives for drugs/ligands. | |
Functional intermediate | Carboxylic acid (3-position) | 5381-25-9 | Benzo[b]thiophene-3-carboxylic acid | ≥96% | Facilitates esterification/amidation/coupling at C3: used to introduce anchors, linkers, or polarity-tuning sites; common in functional materials and drug building blocks. | |
Functional intermediate | Carboxylate ester (2-position) | 22913-24-2 | Methyl benzo[b]thiophene-2-carboxylate | ≥97% | A versatile transformable handle at C2: hydrolysis to the acid, reduction to alcohol/aldehyde, or amidation; used for benzothiophene derivatives in drugs/ligands and material side chains. | |
Functional intermediate | Nitrile (2-position) | 55219-11-9 | 2-Cyanobenzothiophene | ≥95% | The C2 nitrile increases acceptor character and allows further transformation; commonly used as an acceptor end-group precursor in D–A conjugated small molecules/chromophores and for structural modification in drugs/ligands. | |
Functional intermediate | Nitrile (3-position) | 24434-84-2 | Benzo[b]thiophene-3-acetonitrile | ≥97% | A strongly electron-withdrawing nitrile that can be converted to acids/amides/amines; used for D–A molecular energy-level tuning, chromophore/acceptor end-group construction, or drug-lead modification. | |
Functional intermediate | Acetic-acid side chain (3-position) | 1131-09-5 | Benzo[b]thiophene-3-acetic acid | ≥95% | A flexible “linker-bearing” acid: readily forms esters/amides for linker installation, anchoring groups, probes, surface functionalization, polymer grafting, and drug-structure modification. |
Table 4｜Cross-Coupling Building Blocks and Oxidized Sulfur Aromatics (Halides/Boronic Acids and Sulfone Controls)
Category | CAS No. | Aladdin Cat. No. | Name | Specification / Purity | Key features & applications |
Cross-coupling building block | Dibromobenzothiophene (multisite functionalization) | 6287-82-7 | 2,3-Dibromobenzo[b]thiophene | ≥98% | Adjacent dibromo sites enable selective stepwise coupling or ring-closure to build larger fused systems; commonly used for synthesizing multi-substituted benzothiophenes and fused organic-semiconductor scaffolds. | |
Cross-coupling building block | Bromobenzothiophene (2-position) | 5394-13-8 | 2-Bromobenzo[b]thiophene | ≥96% | A common C2 halide building block compatible with Suzuki/Negishi/Stille couplings for installing the benzothiophene fragment and further diversification. | |
Cross-coupling building block | Bromobenzothiophene (3-position) | 7342-82-7 | 3-Bromobenzothiophene | ≥96% | C3 halide enables a topology distinct from C2; used for site-selective construction of 3-substituted benzothiophenes in materials and medicinal chemistry. | |
Cross-coupling building block | Iodobenzothiophene (2-position) | 36748-89-7 | 2-Iodobenzothiophene | ≥97% | C–I undergoes oxidative addition more readily, supporting Suzuki/Negishi/Sonogashira couplings under milder conditions to install C2 benzothiophene fragments for materials/drug diversification. | |
Cross-coupling building block | Iodobenzothiophene (3-position) | 36748-88-6 | 3-Iodobenzo[b]thiophene | ≥95% | Highly reactive C3 C–I bond for mild cross-couplings; used to rapidly build 3-substituted benzothiophenes and diversify materials/drug scaffolds. | |
Cross-coupling building block | Chlorobenzothiophene (3-position) | 7342-86-1 | 3-Chloro-1-benzothiophene | ≥97% | A more “inert” chloro handle: can be coupled under stronger catalytic conditions or used as a starting point for selective downstream functionalization; used for 3-substituted benzothiophenes and fused material scaffolds. | |
Suzuki building block | Boronate ester (2-position) | 376584-76-8 | Benzothiophene-2-boronic acid pinacol ester | ≥98% | A C2 boronate ester for Suzuki coupling to build 2-substituted benzothiophene derivatives; more storage-stable and moisture-manageable than free boronic acids, supporting scale-up and reproducibility. | |
Suzuki building block | Free boronic acid (2-position) | 98437-23-1 | Benzothiophene-2-boronic acid (contains varying amounts of anhydride) | ≥98% | Free boronic acid for rapid Suzuki condition screening; “varying amounts of anhydride” indicates attention to water content/effective boronic-acid equivalents (more sensitive for stoichiometry and reproducibility), recommended to validate on small scale before scale-up. | |
Suzuki building block | Boronate ester (3-position) | 171364-86-6 | Benzo[b]thiophene-3-boronic acid pinacol ester | ≥98% | A stable, weighable boronate ester for Suzuki coupling to install the C3 benzothiophene fragment; widely used in modular assembly for materials and drug building blocks. | |
Suzuki building block | Free boronic acid (3-position) | 113893-08-6 | Benzo[b]thiophene-3-boronic acid (contains varying amounts of anhydride) | ≥97% | C3 boronic acid for Suzuki coupling; the anhydride note highlights the need to manage moisture and effective boronic-acid equivalents—critical for reproducibility and scale-up. | |
Oxidation derivative | Dibenzothiophene sulfone (high polarity/acceptor conversion) | 1016-05-3 | Dibenzothiophene sulfone | ≥97% | Sulfone formation increases polarity and electron-accepting character: used in oxidative desulfurization/mechanistic studies, and as an aromatic sulfone building block to introduce stronger electron-withdrawing fragments into materials/drug molecules. | |
Oxidation derivative | Benzothiophene 1,1-dioxide (sulfone) | 825-44-5 | Benzo[b]thiophene 1,1-dioxide | ≥97% | Oxidation to the sulfone significantly changes energy levels and intermolecular interactions; used to study how oxidation of sulfur heterocycles affects electronic properties/crystallinity/solubility, and as a more polar acceptor-converted fragment. |
Note: The above are representative Aladdin products. For additional specifications, please refer to the product lists at the end of the article, or search the Aladdin website using “product name / CAS / catalog number.”
For more related articles, please see below:
Semiconductor Materials and Their Properties
Semiconductor-Grade Reagents: What They Are and When to Use Them