Overview and Chemical Properties

4-(Chloromethyl)-1-methyl-1H-imidazole hydrochloride (SKU: C191527) is a halomethyl-functionalized imidazole derivative. The compound features a N-methyl group at the 1-position and a reactive chloromethyl substituent at the 4-position of the imidazole ring. The hydrochloride salt form improves stability and handling compared with the free base.

The chloromethyl group acts as a potent electrophile, making this reagent useful for nucleophilic substitution reactions (S_N2) with amines, thiols, alcohols, and other nucleophiles to construct imidazole-containing scaffolds of pharmaceutical and materials interest.

The compound is a solid at ambient temperature and is hygroscopic; therefore, it must be protected from atmospheric moisture at all times to prevent hydrolysis of the chloromethyl group.

Safety and Handling Precautions

As a chloromethyl-bearing reagent, 4-(Chloromethyl)-1-methyl-1H-imidazole hydrochloride should be treated as a potential alkylating agent with associated hazards. Observe the following precautions:

• Personal Protective Equipment (PPE): Wear chemically resistant gloves (nitrile or neoprene), a laboratory coat, safety glasses or goggles, and, where dust may be generated, a NIOSH-approved particulate respirator.
• Ventilation: Handle in a well-ventilated fume hood to minimise inhalation of dust or vapours.
• Skin and Eye Contact: Avoid direct contact. In case of skin contact, wash immediately with copious water for at least 15 minutes. For eye contact, irrigate with water and seek medical attention.
• Waste Disposal: Dispose of waste in accordance with local, regional, and national regulations for halogenated organic compounds.

Consult the Safety Data Sheet (SDS) for C191527 before use. All specific hazard classifications and GHS pictograms should be confirmed from the current SDS.

Reagent Preparation and Dissolution Protocol

Follow this stepwise procedure to prepare stock solutions of 4-(Chloromethyl)-1-methyl-1H-imidazole hydrochloride:

1. Equilibrate to room temperature: Remove the vial from cold storage and allow it to reach room temperature while sealed, preventing condensation from contacting the compound.
2. Weigh under inert atmosphere or quickly: Because of hygroscopicity, weigh the required amount rapidly on a calibrated analytical balance, minimising exposure time.
3. Select appropriate solvent: The compound is expected to dissolve readily in polar aprotic solvents such as DMF or DMSO, and in polar protic solvents including water, methanol, and ethanol. Solvent selection should be guided by downstream reaction requirements. Verify solubility experimentally.
4. Prepare stock solution: Add the weighed solid to a dry, appropriately sized vessel. Add solvent to achieve the desired concentration. Sonicate or stir gently until fully dissolved.
5. Filter if necessary: If particulates are observed, filter through a 0.22 µm PTFE membrane syringe filter.
6. Use promptly or store cold: Use solutions promptly. If storage is required, seal tightly, label with preparation date, and store at –20 °C under inert atmosphere. Avoid repeated freeze-thaw cycles.

Note: Specific solubility data for C191527 should be confirmed experimentally or from the product certificate of analysis.

Synthetic Applications and Reaction Guidance

4-(Chloromethyl)-1-methyl-1H-imidazole hydrochloride serves as a versatile electrophilic synthon for the assembly of imidazole-containing molecules. Key applications include:

• N-Alkylation and O-Alkylation: Reacts with primary or secondary amines and alcohols under mild basic conditions (e.g., K₂CO₃ in DMF or acetonitrile) to provide N- or O-alkylated products bearing the 1-methylimidazol-4-ylmethyl group.
• S-Alkylation: Reacts efficiently with thiols under mild conditions to form thioether linkages, useful in the preparation of prodrug linkers and bioconjugate anchors.
• Pharmaceutical Intermediate Synthesis: The 1-methylimidazole scaffold is present in a range of biologically active compounds and drug candidates; this reagent allows rapid introduction of this unit into target molecules.
• Coordination Chemistry: The imidazole nitrogen can serve as a ligand after the chloromethyl group has been displaced, enabling construction of metal-chelating frameworks.

General reaction conditions (illustrative; optimise for each specific reaction):

• Base: K₂CO₃, Et₃N, or NaH (anhydrous conditions for NaH)
• Solvent: DMF, MeCN, or THF
• Temperature: 0 °C to 80 °C depending on nucleophile reactivity
• Typical reaction time: 1–24 h monitored by TLC or HPLC

All specific reaction yields, selectivities, and conditions must be determined experimentally and are not guaranteed by this protocol.

Quality Control and Troubleshooting

To ensure reliable experimental results when using C191527, observe the following quality control practices:

• Identity Verification: Confirm compound identity by ¹H NMR and/or HRMS before critical experiments. Key NMR signals include the imidazole ring protons (aromatic region), the N-CH₃ singlet (~3.7 ppm), and the CH₂Cl singlet (~4.5–4.7 ppm). Exact chemical shifts should be confirmed against the certificate of analysis.
• Purity Check: Assess purity by HPLC (reverse-phase C18 column, UV detection at 220 nm) or by ¹H NMR integration. Use material meeting the purity specification stated on the certificate of analysis.
• Moisture Content: For sensitive reactions, perform Karl Fischer titration to quantify residual water. Excess moisture will hydrolyse the chloromethyl group to the corresponding hydroxymethyl compound, reducing yield.

Common issues and remedies:

• Low reaction yield: Check moisture level of reagent and solvent; ensure adequate base stoichiometry; confirm nucleophile is not over-protected.
• Formation of bis-alkylated product: Reduce equivalents of C191527 or lower reaction temperature.
• Poor solubility of starting material: Switch to a more polar solvent or warm gently while stirring.