2-Chloro-5-chloromethylthiazole
[CAS# 105827-91-6]

Identification

• Classification: Chemical pesticide >> Insecticide intermediate
• Name: 2-Chloro-5-chloromethylthiazole
• Molecular Formula: C₄H₃Cl₂NS
• Molecular Weight: 168.04
• CAS Registry Number: 105827-91-6
• EC Number: 429-830-5
• SMILES: C1=C(SC(=N1)Cl)CCl

Properties

• Density: 1.5±0.1 g/cm³, Calc.^*
• Melting point: 31 °C
• Index of Refraction: 1.584, Calc.^*
• Boiling Point: 268.6±32.0 °C (760 mmHg), Calc.^*
• Flash Point: 116.3±25.1 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS06;GHS05;GHS07;GHS09 Danger
• Risk Statements: H302-H310-H311-H314-H317-H318-H411
• Safety Statements: P260-P261-P262-P264-P264+P265-P270-P272-P273-P280-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P330-P333+P317-P361+P364-P362+P364-P363-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Skin sensitization	Skin Sens.	1	H317
Skin corrosion	Skin Corr.	1B	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	2	H310
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	3	H311

Discovery and Applications

2-Chloro-5-chloromethylthiazole is an organosulfur compound with the molecular formula C₄H₃Cl₂NS, recognized for its role as an intermediate in synthesizing various agrochemicals and pharmaceuticals. The compound belongs to the thiazole family, characterized by a five-membered ring structure containing both sulfur and nitrogen atoms. The discovery of thiazoles, including chlorinated derivatives like 2-Chloro-5-chloromethylthiazole, dates back to the late 19th century when heterocyclic compounds were being systematically studied for their reactivity and potential uses in medicine and agriculture. 2-Chloro-5-chloromethylthiazole stands out for its particular chemical reactivity, which has made it a valuable intermediate in the synthesis of complex molecules.

Structurally, 2-Chloro-5-chloromethylthiazole contains a chlorinated thiazole ring, with chlorine atoms positioned at the second and fifth carbon atoms, respectively. This substitution pattern enhances the compound’s reactivity, particularly in nucleophilic substitution reactions. The chloromethyl group on the thiazole ring is highly reactive, enabling it to act as an electrophile in reactions with various nucleophiles. Due to this reactivity, 2-Chloro-5-chloromethylthiazole is typically synthesized under controlled conditions to prevent side reactions and preserve the compound’s stability.

In agricultural chemistry, 2-Chloro-5-chloromethylthiazole is an important intermediate in synthesizing several pesticides and fungicides, where it contributes to compounds designed to protect crops from pests and fungal infections. Notably, this compound is used in producing neonicotinoid insecticides, a class known for their effectiveness in controlling a wide range of insects while minimizing harm to crops. These insecticides operate by targeting specific neural pathways in insects, providing effective pest control solutions in agriculture. In pharmaceutical research, the thiazole ring system, enhanced by chlorination, is often incorporated into compounds with antimicrobial, anti-inflammatory, and other therapeutic properties.

The high reactivity of 2-Chloro-5-chloromethylthiazole makes it suitable for applications beyond agriculture. Its chlorinated thiazole structure is leveraged in the development of specialized materials and in fine chemical synthesis, where it contributes to the formation of complex, heterocyclic compounds. Its uses in these industries, however, are managed under stringent guidelines due to the potential environmental and health hazards associated with chlorinated organosulfur compounds.

The discovery and industrial application of 2-Chloro-5-chloromethylthiazole underscore the value of thiazole derivatives in modern chemistry, particularly in agrochemical synthesis and pharmaceutical research. Its unique structure and reactivity continue to support innovations in pest control, medicine, and synthetic chemistry.

References

2011. 2-Chloro-5-chloro-meth-yl-1,3-thia-zole. Acta Crystallographica Section E, 67(6), o1496.
DOI: 10.1107/s1600536811019052

2017. Sulfur-Containing Agrochemicals. Topics in Current Chemistry, 375(6), 82.
DOI: 10.1007/s41061-017-0169-9

2004. Advances in the synthesis of neonicotinoids. Russian Journal of Organic Chemistry, 40(12), 1697-1707.
DOI: 10.1007/s11178-005-0089-y