1-Chloronaphtho[2,3-b]benzofuran
[CAS 2170644-12-7]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Lactone and oxygen-containing heterocyclic compound >> Furan and pyran
• Name: 1-Chloronaphtho[2,3-b]benzofuran
• Molecular Formula: C₁₆H₉ClO
• Molecular Weight: 252.70
• CAS Registry Number: 2170644-12-7
• SMILES: C1=CC=C2C=C3C(=CC2=C1)C4=C(O3)C=CC=C4Cl

Properties

• Density: 1.4±0.1 g/cm³ Calc.^*
• Boiling point: 424.4±18.0 °C 760 mmHg (Calc.)^*
• Flash point: 210.5±21.2 °C (Calc.)^*
• Index of refraction: 1.763 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P261-P264-P270-P271-P280-P302+P352-P304+P340-P305+P351+P338-P321-P330-P362+P364-P403+P233-P405-P501

chemBlink Chemical Story

1-Chloronaphtho[2,3-b]benzofuran, CAS 2170644-12-7, belongs to the family of fused oxygen-containing polycyclic aromatics. Several rings are locked together around a benzofuran core, producing a rigid pi-conjugated framework with far less conformational freedom than a structure assembled from phenyl rings connected by ordinary single bonds. That rigidity is one reason fused heteroaromatic units are widely explored as building blocks for organic electronic and luminescent materials.

In molecular electronics, the shape of a molecule matters alongside its elemental composition. A rigid fused aromatic system can support extended electronic delocalization and can influence how molecules pack in a solid film. Packing, in turn, affects intermolecular electronic interactions, charge transport and photophysical behavior. Introducing an oxygen atom into the fused framework changes the electronic distribution relative to an all-carbon polycyclic aromatic hydrocarbon and gives synthetic chemists another way to tune frontier orbital energies.

The chlorine substituent adds a second kind of usefulness. An aryl chloride can sometimes be retained as part of the final molecule, but under appropriately designed catalytic conditions it can also serve as a functionalization handle. This makes chlorinated fused heteroarenes valuable intermediates: the difficult polycyclic core can be constructed first, then the perimeter can be elaborated with aryl, amino or other substituents required by a final materials design.

Patent literature supports this context. Korean patent KR20230080351A describes organic light-emitting compounds and explicitly uses chloronaphtho[2,3-b]benzofuran-derived starting materials in synthetic examples. Other patents describe preparation of chloronaphthobenzofuran cores as intermediates for organic materials. These records establish the relevance of this fused scaffold to OLED-oriented synthesis, although they do not mean that CAS 2170644-12-7 itself is necessarily used directly as the emitting material.

That distinction is important. Specialty intermediates are often commercially useful because they provide access to a family of final compounds, not because the intermediate has the optimized optical or electronic properties required in a device. Public database records for CAS 2170644-12-7 mainly provide identity and predicted physical properties, while the richer application story comes from related patent chemistry.

The compound is therefore best understood as a rigid, chlorinated heteroaromatic construction platform. Its fused rings provide shape and conjugation; the oxygen atom modifies the electronic framework; the chlorine provides a possible point for further synthesis. In advanced organic materials, such a molecule is valuable because it lets chemists separate two difficult tasks: first build the rigid core, then tune its outer substituents for the final device.

References:
1. ChemicalBook, CAS 2170644-12-7, identity and structure record.
2. KR20230080351A, Novel compound and organic light emitting device comprising the same.
3. CN115960062B, Preparation method of chloronaphtho[2,3-b]benzofuran.

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