Introducing a methyl group into a complex organic molecule may appear to be a simple transformation, but in pharmaceutical and advanced organic synthesis, where and how the methyl group is introduced can have a significant impact on the final molecule.

This is where Methyl trifluoromethanesulfonate, commonly known as Methyl triflate or MeOTf, becomes particularly valuable.

With CAS No. 333-27-7, Methyl trifluoromethanesulfonate is a highly reactive electrophilic methylating reagent used in organic synthesis. Its combination of a reactive methyl group and the excellent leaving-group characteristics of triflate makes it suitable for methylation reactions involving a range of nucleophilic substrates.

The compound is also known as:

• · Methyl trifluoromethanesulfonate 
• · Methyl triflate 
• · MeOTf 
• · Trifluoromethanesulfonic acid methyl ester 
• · Methanesulfonic acid, trifluoro-, methyl ester 

PubChem identifies Methyl triflate under CAS 333-27-7, with molecular formula C₂H₃F₃O₃S and molecular weight approximately 164.11 g/mol.

Its applications extend beyond general organic synthesis. Methyl triflate is particularly relevant to the preparation of pharmaceutical intermediates, heterocyclic compounds, antibacterial drug intermediates, central nervous system compounds, and radiolabeled PET tracers.

For pharmaceutical and specialty chemical manufacturers, understanding both its synthetic value and its demanding handling requirements is essential when selecting a reliable supplier.

1. What Is Methyl Trifluoromethanesulfonate?

Methyl trifluoromethanesulfonate is an organic sulfonate ester containing a highly electrophilic methyl group.

Its basic product information is summarized below:

PubChem reports a molecular formula of C₂H₃F₃O₃S and molecular weight of 164.11 g/mol, while commercial technical references report a boiling point around 94–99°C and density around 1.45 g/mL at 25°C.

Different suppliers may report slightly different physical-property values depending on measurement conditions. Therefore, customers should use the supplier’s current specification and Certificate of Analysis for batch-specific quality information.

2. What Makes Methyl Triflate Such an Effective Methylating Agent?

The central feature of Methyl triflate is its high electrophilicity.

In a methylation reaction, the methyl group is transferred to an appropriate nucleophilic site on the substrate.

The triflate group functions as an excellent leaving group, allowing the methyl group to participate in highly efficient electrophilic methyl transfer.

A simplified representation is:

Nucleophile + MeOTf → Methylated product + triflate-derived species

Depending on the substrate and reaction conditions, methylation can occur at different nucleophilic sites.

Potential reaction centers can include:

• · Oxygen
• · Nitrogen
• · Sulfur
• · Carbon

This versatility is one of the major reasons Methyl triflate is widely used in advanced organic synthesis.

TCI describes Methyl trifluoromethanesulfonate as a powerful methylating agent, while Sigma-Aldrich likewise identifies it as a highly reactive methylating reagent.

3. Methyl Triflate Compared with Conventional Methylating Reagents

Organic chemists have access to several methylating reagents, including:

• · Methyl iodide
• · Dimethyl sulfate
• · Methyl triflate
• · Other activated methyl donors

The appropriate reagent depends on the substrate, reaction conditions, desired selectivity, scale, and safety requirements.

Methyl triflate is particularly attractive when high electrophilicity and efficient methyl transfer are required.

Its advantages can include:

High Reactivity

The activated methyl group can react efficiently with suitable nucleophiles.

Mild Reaction Potential

Some methylation reactions can be performed under relatively mild conditions, which may be advantageous for sensitive substrates.

Synthetic Flexibility

Methyl triflate can participate in O-, N-, S-, and selected C-methylation chemistry depending on the substrate and reaction system.

Advanced Synthetic Applications

Its high reactivity makes it useful when conventional methylating reagents do not provide the required conversion or reaction efficiency.

However, greater reactivity also means greater handling requirements.

Methyl triflate is classified by major suppliers as a hazardous substance with flammability, severe skin/eye damage, and acute toxicity hazards.

Therefore, reactivity and safety must always be considered together.

4. Why Methylation Matters in Pharmaceutical Chemistry

Methyl groups may appear structurally small, but methylation can have significant consequences for a molecule’s properties.

Introducing a methyl group can influence:

• · Molecular polarity
• · Lipophilicity
• · Hydrogen-bonding characteristics
• · Metabolic behavior
• · Steric environment
• · Molecular conformation
• · Biological activity

For pharmaceutical researchers, this means methylation can be used as a tool for fine-tuning molecular structures during medicinal chemistry and process development.

In some cases, the methyl group is part of the final drug structure.

In others, methylation may be used to prepare an intermediate that undergoes further transformations.

This is why efficient methylating reagents such as Methyl triflate remain relevant to pharmaceutical synthesis.

5. Application in Antitumor Pharmaceutical Intermediates

One important application area for Methyl trifluoromethanesulfonate is the synthesis of pharmaceutical intermediates associated with antitumor drug development.

Complex pharmaceutical structures frequently contain methoxy, N-methyl, or other methyl-substituted functional groups.

When a synthetic route requires selective introduction of a methyl group, MeOTf can provide a highly reactive methyl source.

This is especially relevant when:

• · The substrate is sterically hindered
• · Conventional methylating reagents provide insufficient conversion
• · A sensitive substrate requires carefully controlled reaction conditions
• · Efficient late-stage functionalization is desirable

The actual suitability of Methyl triflate depends on the specific substrate and synthetic route.

For commercial pharmaceutical manufacturing, process chemists must also consider reagent purity, impurity profile, reaction safety, and downstream purification.

6. Methyl Triflate in Quinolone and Heterocyclic Chemistry

Heterocyclic chemistry is another important field in which highly reactive methylating reagents can play a role.

Many antibacterial and pharmaceutical compounds contain nitrogen-, oxygen-, or sulfur-containing heterocycles.

Selective methylation can be used to modify these heterocyclic frameworks or to construct intermediates required for subsequent synthetic steps.

Methyl triflate is particularly useful when a highly activated methylating reagent is needed for difficult substrates.

Its applications can therefore intersect with the synthesis and modification of:

• · Quinolone-related structures
• · Nitrogen heterocycles
• · Oxygen-containing heterocycles
• · Sulfur-containing heterocycles
• · Other medicinally relevant heterocyclic intermediates

The specific reaction site is determined by substrate structure and reaction conditions rather than by the reagent alone.

For this reason, professional chemical suppliers should provide accurate product identification and technical information rather than making broad claims about a specific pharmaceutical synthesis without supporting data.

7. Methyl Triflate and Central Nervous System Drug Research

Methylation chemistry is also important in the development of central nervous system (CNS) compounds.

CNS-active molecules often contain complex heterocyclic and aromatic structures where small structural modifications can affect:

• · Receptor binding
• · Lipophilicity
• · Molecular transport
• · Metabolic stability
• · Pharmacological activity

Methyl triflate can be used as a highly reactive methyl donor when researchers need to introduce methyl groups into suitable molecular structures.

This makes it useful in medicinal chemistry and advanced intermediate synthesis involving CNS-related compounds.

The reagent’s high reactivity can be particularly valuable during the preparation of structurally complex molecules where conventional alkylation methods may be less effective.

8. Methyl Triflate in PET Tracer Chemistry

One of the more specialized applications of Methyl triflate is its role in the preparation of carbon-11 labeled PET tracers.

This application is particularly important because carbon-11 has a short radioactive half-life of approximately 20 minutes.

As a result, radiochemistry requires reactions that are:

• · Fast
• · Efficient
• · Selective
• · Compatible with automated synthesis systems

[¹¹C]Methyl triflate can serve as a methylating agent in radiolabeling chemistry.

It enables the rapid introduction of a carbon-11 methyl group into suitable precursor molecules for PET imaging research.

This makes methyl triflate relevant to the development of PET tracers used in neuroscience and other biomedical imaging applications.

The importance of reaction speed is especially clear in this context.

With a short-lived radionuclide, every unnecessary processing step can reduce the amount of usable labeled product.

Consequently, highly efficient methylation chemistry is an important part of radiotracer synthesis.

9. Why PET Applications Require Different Reagent Considerations

The requirements for PET radiochemistry differ from conventional pharmaceutical synthesis.

In conventional synthesis, reaction time may be measured in hours.

In radiochemistry, the radioactive decay clock is continuously running.

Therefore, researchers often prioritize:

Reaction speed + conversion + selectivity + reproducibility

rather than simply reagent cost.

Methyl triflate’s high reactivity makes it particularly useful in this environment.

For radiochemical applications, however, reagent quality, precursor compatibility, automated synthesis conditions, and validated procedures must all be considered.

The reagent should therefore be evaluated as part of the complete radiochemical process rather than as an isolated chemical.

10. Physical Properties and Handling Requirements

Methyl trifluoromethanesulfonate is a volatile, highly reactive liquid.

Published supplier data report:

• · Boiling point: approximately 94–99°C 
• · Flash point: approximately 38°C 
• · Density: approximately 1.45–1.49 g/mL 
• · Refractive index: approximately 1.326 

The compound is also sensitive to moisture and is generally handled under controlled conditions.

SHLZ Pharma’s product information specifies storage at 2–8°C, sealed, dry, and under an inert gas such as nitrogen or argon.

Safety information from TCI and Sigma-Aldrich identifies serious hazards, including flammability, corrosivity/severe skin burns and eye damage, and acute toxicity.

Therefore, Methyl triflate should only be handled by appropriately trained personnel using the current SDS, suitable engineering controls, appropriate PPE, and validated procedures.

11. Why Purity Matters for Methyl Triflate

For a highly reactive reagent, nominal assay alone does not always tell the complete quality story.

Potential impurities can influence downstream reactions, particularly when the reagent is used in:

• · Pharmaceutical intermediate synthesis
• · High-value medicinal chemistry
• · Radiochemistry
• · Multi-step process chemistry

Important quality considerations may include:

Chemical Assay

Confirms the amount of target compound.

Water Content

Important because Methyl triflate is moisture sensitive and can undergo hydrolytic degradation.

Impurity Profile

Can influence reaction performance and downstream purification.

Appearance

Changes in appearance may warrant investigation according to the applicable specification.

Batch Consistency

Particularly important when transferring a laboratory reaction into repeated or commercial production.

For customers working with Methyl triflate, a reliable COA and batch-specific analytical documentation can therefore be valuable parts of supplier qualification.

12. What Should Buyers Check Before Purchasing Methyl Triflate?

When sourcing Methyl trifluoromethanesulfonate CAS 333-27-7, procurement teams should confirm several points.

1. Chemical Identity

Verify:

Methyl trifluoromethanesulfonate

CAS No. 333-27-7

2. Purity Specification

Confirm the required assay and analytical method.

3. Moisture Control

Ask how the material is packaged and protected against moisture.

4. Storage Conditions

Confirm recommended storage temperature and handling requirements.

5. Packaging

The packaging should be suitable for a volatile, reactive, moisture-sensitive reagent.

6. Documentation

Request:

• · COA
• · SDS
• · Specification
• · Batch information
• · Packaging information
• · Relevant analytical data

7. Supply Stability

For pharmaceutical manufacturing, a reliable supply chain is important because replacing a qualified reagent supplier can require additional evaluation and process verification.

13. SHLZ Pharma’s Methyl Triflate Supply

SHLZ Pharma supplies Methyl trifluoromethanesulfonate CAS 333-27-7 for customers working in pharmaceutical synthesis, specialty chemical development, and advanced organic chemistry.

The company positions the product within its broader portfolio of pharmaceutical intermediates and specialty chemicals.

For international customers, a suitable supply program should address more than product availability.

It should also provide:

Consistent Product Quality

Stable specifications support reproducible downstream synthesis.

Batch Documentation

COA and relevant technical documentation help customers qualify the material.

Appropriate Packaging

Moisture-sensitive and volatile materials require packaging and shipping arrangements appropriate to their physical and chemical characteristics.

Flexible Supply

Different customers may require laboratory quantities, development-scale quantities, or larger commercial volumes.

Technical Communication

Clear communication regarding purity, storage, packaging, and analytical requirements helps reduce procurement uncertainty.

14. Methyl Triflate in the Broader Specialty Chemical Market

The market for highly reactive methylating reagents is closely connected to several areas of modern chemical development.

Pharmaceutical Development

Complex drug molecules frequently require selective functional-group modification.

Advanced Organic Synthesis

Research chemists require increasingly efficient methods for constructing sophisticated molecular architectures.

Heterocyclic Chemistry

Methylation can modify nitrogen-, oxygen-, and sulfur-containing heterocycles.

Radiopharmaceutical Research

Fast methylation chemistry is valuable when working with short-lived radionuclides such as carbon-11.

Specialty Chemical Manufacturing

Highly reactive intermediates can be used to manufacture higher-value downstream products.

These applications create a demand for chemical suppliers capable of delivering not only the reagent itself but also consistent quality and appropriate technical documentation.

15. Frequently Asked Questions

What is Methyl trifluoromethanesulfonate?

Methyl trifluoromethanesulfonate is a highly reactive electrophilic methylating reagent commonly known as Methyl triflate or MeOTf.

What is the CAS number of Methyl triflate?

The CAS number is 333-27-7. PubChem also lists this CAS number among the compound’s identifiers.

What is the molecular formula of Methyl triflate?

Its molecular formula is C₂H₃F₃O₃S, with a molecular weight of approximately 164.10–164.11 g/mol.

What is Methyl triflate used for?

Methyl triflate is primarily used as a highly reactive methylating agent in organic synthesis. Applications include pharmaceutical intermediates, heterocyclic chemistry, CNS-related compounds, and PET radiotracer synthesis.

Is Methyl triflate used in PET tracer synthesis?

Yes. Methyl triflate chemistry is used in radiochemical methylation, including the preparation of carbon-11 labeled compounds for PET research.

Why is Methyl triflate so reactive?

Its methyl group is strongly electrophilic and is attached to a triflate-derived leaving group, allowing efficient methyl transfer to suitable nucleophiles.

How should Methyl triflate be stored?

Supplier information recommends controlled storage conditions, commonly 2–8°C, in a sealed, dry environment with inert-gas protection where specified. Customers should always follow the latest supplier SDS and product specification.

Is Methyl triflate hazardous?

Yes. It is a highly reactive hazardous chemical. Major supplier safety information identifies flammability, severe skin and eye hazards, and acute toxicity risks. Appropriate engineering controls, PPE, and trained handling are required.

Conclusion

Methyl trifluoromethanesulfonate (CAS No. 333-27-7), widely known as Methyl triflate or MeOTf, is a highly reactive methylating reagent with an important role in advanced organic and pharmaceutical synthesis.

With the molecular formula C₂H₃F₃O₃S and molecular weight of approximately 164.10 g/mol, it provides an efficient source of electrophilic methyl groups for suitable O-, N-, S-, and C-methylation reactions.

Its value extends across several specialized fields, including antitumor pharmaceutical intermediates, quinolone and heterocyclic chemistry, CNS drug research, and PET tracer development.

Its application in radiochemical methylation is particularly notable because short-lived isotopes such as carbon-11 require highly efficient reaction processes.

At the same time, the exceptional reactivity of Methyl triflate creates significant requirements for storage, transportation, handling, and quality control. It is a volatile, moisture-sensitive, flammable, corrosive, and toxic reagent, and therefore should be handled strictly according to applicable safety documentation.

For pharmaceutical companies and research organizations sourcing Methyl trifluoromethanesulfonate CAS 333-27-7, the right supplier should provide more than competitive pricing. Chemical identity, purity, batch consistency, moisture control, packaging, documentation, and reliable supply capability are all important considerations.

SHLZ Pharma provides Methyl trifluoromethanesulfonate for international customers requiring a reliable source of this high-performance methylating reagent for pharmaceutical synthesis, specialty chemical development, and advanced research applications.