2,3-Dichlorobenzaldehyde
[CAS# 6334-18-5]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty aldehyde (containing acetal, hemiacetal)
• Name: 2,3-Dichlorobenzaldehyde
• Molecular Formula: C₇H₄Cl₂O
• Molecular Weight: 175.01
• CAS Registry Number: 6334-18-5 (31155-09-6)
• EC Number: 228-711-3
• SMILES: C1=CC(=C(C(=C1)Cl)Cl)C=O

Properties

• Density: 1.4±0.1 g/cm³, Calc.^*, 1.33 g/mL (Expl.)
• Melting point: 64-67 °C (Expl.)
• Index of Refraction: 1.601, Calc.^*
• Boiling Point: 242.9±20.0 °C (760 mmHg), Calc.^*, 143-145 °C (Expl.)
• Flash Point: 99.2±22.3 °C, Calc.^*, 135 °C (Expl.)

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

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H314-H315-H335-H412
• Safety Statements: P260-P261-P264-P271-P273-P280-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P319-P321-P332+P317-P362+P364-P363-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin irritation	Skin Irrit.	2	H315
Skin sensitization	Skin Sens.	1A	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Eye irritation	Eye Irrit.	2B	H320
Acute hazardous to the aquatic environment	Aquatic Acute	2	H401
Skin corrosion	Skin Corr.	1C	H314
Eye irritation	Eye Irrit.	2	H319
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1A	H314

• Transport Information: UN 3261

Discovery and Applications

2,3-Dichlorobenzaldehyde, with the molecular formula C7H4Cl2O, is an aromatic compound consisting of a benzene ring substituted with two chlorine atoms at the 2- and 3-positions and an aldehyde group at the 1-position. This compound has garnered attention due to its versatility in organic synthesis and applications in various fields, including pharmaceuticals, agrochemicals, and materials science.

The compound was first synthesized through chlorination processes applied to benzaldehyde derivatives. Early chlorination techniques involved the use of reagents such as chlorine gas or sulfuryl chloride under controlled conditions to selectively introduce chlorine atoms into aromatic rings. The development of such halogenated aldehydes provided chemists with intermediates for more complex synthetic pathways.

2,3-Dichlorobenzaldehyde is a valuable building block in the synthesis of bioactive molecules. In pharmaceutical research, it serves as a precursor for the development of antibacterial, antifungal, and anti-inflammatory agents. The dichloro substitution pattern enhances the reactivity and pharmacological properties of derivatives, making it a useful scaffold for medicinal chemistry programs.

In the field of agrochemicals, 2,3-dichlorobenzaldehyde is employed in the synthesis of herbicides, pesticides, and fungicides. Its structural features contribute to the biological activity of these compounds, helping to inhibit the growth of unwanted pests and pathogens in agriculture.

Additionally, 2,3-dichlorobenzaldehyde finds use in material science, particularly in the development of liquid crystals and polymers. The compound’s aromatic structure and electron-withdrawing chlorine atoms impart desirable properties such as rigidity and thermal stability to the resulting materials.

Industrial production methods for 2,3-dichlorobenzaldehyde have evolved to prioritize efficiency and environmental safety. Modern techniques utilize catalytic processes and optimized reaction conditions to minimize by-products and waste. Advances in green chemistry have also explored more sustainable methods for halogenation reactions.

In summary, 2,3-dichlorobenzaldehyde is a key intermediate in the synthesis of pharmaceuticals, agrochemicals, and advanced materials. Its discovery and applications highlight the importance of halogenated aromatic compounds in modern chemistry.

References

2011. Intermolecular interactions and unexpected isostructurality in the crystal structures of the dichlorobenzaldehyde isomers. Acta crystallographica. Section B, Structural science, 67(5).
DOI: 10.1107/s0108768111035786

2012. Synthesis of tetrazolodiazepines by a five-centered four-component azide Ugi reaction. Scope and limitations. Russian Chemical Bulletin, 61(8).
DOI: 10.1007/s11172-012-0214-3

2016. Catalyst-Free Synthesis of 2-Arylbenzothiazoles in an Air/DMSO Oxidant System. Synlett, 27(7).
DOI: 10.1055/s-0035-1561575