6-Methoxypyridine-2-boronic acid Pinacol Ester: Properties & Uses

6-Methoxypyridine-2-boronic acid pinacol ester is a stable, air-tolerant heteroarylboronic acid ester widely employed as a versatile building block in palladium-catalyzed Suzuki–Miyaura cross-coupling reactions for the synthesis of methoxypyridine-containing pharmaceuticals, agrochemicals, and functional materials.

Chemical Name

6-Methoxypyridine-2-boronic acid pinacol ester

SKU / Catalog Number

M358831

Core Functional Group

Arylboronic acid pinacol ester (Bpin)

Primary Application

Suzuki–Miyaura cross-coupling partner

Key Structural Feature

Methoxy group at position 6 of the pyridine ring, boronate ester at position 2

Stability

More stable toward hydrolysis than the corresponding free boronic acid due to pinacol ester protection

Chemical Identity and Structure

6-Methoxypyridine-2-boronic acid pinacol ester belongs to the class of heteroarylboronic acid pinacol esters, in which the reactive boronic acid group (–B(OH)₂) is protected as a cyclic ester with pinacol (2,3-dimethyl-2,3-butanediol). The molecule features a pyridine ring bearing a methoxy substituent at the 6-position and a Bpin group at the 2-position. This substitution pattern provides a handle for selective carbon–carbon bond formation at the C-2 position of the pyridine ring while the C-6 methoxy group can influence electronic density and direct further functionalization.

The pinacol ester form offers significant practical advantages over the parent boronic acid: improved crystallinity, enhanced bench stability, reduced protodeboronation under mildly acidic aqueous conditions, and easier handling and storage. The compound is catalogued at Aladdin Scientific under SKU M358831.

Key Physicochemical Properties

As a heteroarylboronic acid pinacol ester, 6-Methoxypyridine-2-boronic acid pinacol ester typically presents as a white to off-white crystalline solid at room temperature. The pinacol ester motif confers the following general characteristics shared by this compound class:

• Hydrolytic stability: The cyclic boronate ester is more resistant to hydrolysis than free arylboronic acids, enabling storage at ambient conditions when kept dry.
• Solubility: Soluble in common organic solvents such as tetrahydrofuran (THF), 1,4-dioxane, dimethyl sulfoxide (DMSO), ethyl acetate, and dichloromethane; sparingly soluble in water.
• Reactivity: The Bpin group undergoes transmetalation with palladium complexes under standard Suzuki–Miyaura conditions, and can be hydrolyzed to the free boronic acid when required.

Note: Specific values for molecular weight, melting point, and purity are available on the Aladdin Scientific product page for M358831. Researchers should consult the certificate of analysis for lot-specific data.

Applications in Organic Synthesis

Suzuki–Miyaura Cross-Coupling: The primary use of 6-Methoxypyridine-2-boronic acid pinacol ester is as a nucleophilic coupling partner in palladium-catalyzed Suzuki–Miyaura reactions. It reacts with aryl or heteroaryl halides (chlorides, bromides, iodides) and triflates in the presence of a palladium catalyst (e.g., Pd(PPh₃)₄, Pd(dppf)Cl₂) and a base (e.g., K₂CO₃, Cs₂CO₃) to furnish biaryl and heteroaryl–aryl coupled products containing the 6-methoxypyridin-2-yl motif.

Medicinal Chemistry and Drug Discovery: The 6-methoxypyridin-2-yl fragment is a privileged scaffold found in bioactive molecules. Coupling reactions with this boronate ester provide rapid access to compound libraries for structure–activity relationship (SAR) studies targeting diverse biological pathways.

Agrochemical Synthesis: Methoxypyridine-containing structures appear in commercial herbicides, fungicides, and insecticides. This building block facilitates efficient construction of such frameworks.

Materials Science: Pyridine-containing conjugated materials synthesized via Suzuki coupling are of interest in organic electronics, including OLEDs and organic photovoltaics.

Handling, Storage, and Safety Guidelines

Storage: Store in a cool, dry, well-ventilated area, away from moisture and incompatible materials. The pinacol ester form is more stable than the free boronic acid; however, exposure to moisture over prolonged periods can lead to gradual hydrolysis. Sealing under inert gas (nitrogen or argon) after opening is recommended for long-term preservation of reagent quality.

Handling: Use standard laboratory personal protective equipment (PPE) including lab coat, chemical-resistant gloves, and safety glasses when handling this compound. Avoid generating dust. Work in a well-ventilated fume hood.

Disposal: Dispose of in accordance with local, regional, and national environmental regulations. Do not dispose of down the drain.

Always consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for M358831 before use. The SDS contains authoritative hazard classification, first-aid measures, and regulatory information specific to this product lot.

Ordering Information

6-Methoxypyridine-2-boronic acid pinacol ester is available from Aladdin Scientific under catalog number M358831. To place an order, request a quote, or obtain a certificate of analysis, please visit the Aladdin Scientific website or contact your local Aladdin representative. Volume pricing and custom packaging may be available for larger quantities; please inquire with our sales team.

Cross-reference: This product is also known by the Santa Cruz Biotechnology reference number sc-262866, which may assist procurement teams reconciling supplier catalogues.

Frequently asked questions

What is 6-Methoxypyridine-2-boronic acid pinacol ester used for?

It is primarily used as a coupling partner in palladium-catalyzed Suzuki–Miyaura cross-coupling reactions to introduce the 6-methoxypyridin-2-yl group into target molecules. Applications span medicinal chemistry, agrochemical synthesis, and materials science.

What is the advantage of using the pinacol ester form over the free boronic acid?

The pinacol ester form is more stable toward hydrolysis and protodeboronation, easier to handle and store, and often crystalline, facilitating accurate weighing. Under cross-coupling conditions the Bpin group undergoes transmetalation analogously to the free boronic acid, without significant loss of reactivity.

How should I store M358831 to maintain its quality?

Store M358831 in a tightly closed container in a cool, dry location away from moisture. After opening, reseal under an inert atmosphere of nitrogen or argon to prevent moisture-induced hydrolysis of the boronate ester. Consult the SDS and certificate of analysis for lot-specific storage temperature recommendations.

Can this boronate ester be hydrolyzed to the free boronic acid if needed?

Yes. Pinacol boronate esters can be hydrolyzed to the corresponding free boronic acid under mildly acidic aqueous conditions (e.g., dilute HCl or aqueous acetone with periodic acid), or under basic conditions followed by acidification. The exact protocol should be optimized for the specific experimental context.

What palladium catalysts are compatible with this reagent in Suzuki coupling?

Commonly used palladium catalysts include Pd(PPh3)4, Pd(dppf)Cl2, Pd(OAc)2 with phosphine ligands, and Pd2(dba)3 with supporting ligands. The choice of catalyst and base should be optimized based on the electrophilic coupling partner and reaction conditions.

References

1. Miyaura, N.; Suzuki, A. Palladium-Catalyzed Cross-Coupling Reactions of Organoboron Compounds. Chemical Reviews 1995, 95 (7), 2457–2483. doi:10.1021/cr00039a007
2. Hall, D. G. (Ed.). Boronic Acids: Preparation and Applications in Organic Synthesis, Medicine and Materials, 2nd ed.; Wiley-VCH: Weinheim, 2011.
3. Billingsley, J. M.; Sherwood, J.; Sherwood, T. C. Advances in heteroarylboronic acid and ester chemistry for cross-coupling. Organic & Biomolecular Chemistry 2020 (general reference — specific article details require verification).

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.