Diethyl(3-pyridyl)borane
[CAS# 89878-14-8]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyridine compound >> Ethylpyridine
• Name: Diethyl(3-pyridyl)borane
• Synonyms: Diethyl(pyridin-3-yl)borane
• Molecular Formula: C₉H₁₄BN
• Molecular Weight: 147.02
• CAS Registry Number: 89878-14-8
• EC Number: 627-082-6
• SMILES: B(CC)(CC)C1=CN=CC=C1

Properties

• Density: 0.9±0.1 g/cm³, Calc.^*
• Melting point: 172-175 °C (Expl.)
• Index of Refraction: 1.457, Calc.^*
• Boiling Point: 205.9±22.0 °C (760 mmHg), Calc.^*
• Flash Point: 78.3±22.3 °C, Calc.^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Flammable solids	Flam. Sol.	1	H228
Acute toxicity	Acute Tox.	4	H302

Discovery and Applications

Diethyl(3-pyridyl)borane is an organoboron compound that has gained attention for its unique chemical properties and versatile applications in various fields, including catalysis, organic synthesis, and material science. This compound is part of a broader class of boron-containing molecules, which are known for their ability to act as Lewis acids and for their utility in a variety of chemical reactions. Diethyl(3-pyridyl)borane, in particular, is characterized by a boron atom bonded to two ethyl groups and a pyridine ring at the 3-position, which introduces additional electronic effects and reactivity.

The discovery of diethyl(3-pyridyl)borane can be attributed to the ongoing efforts in the development of new reagents and catalysts that can facilitate efficient chemical transformations. The unique properties of the pyridine group, which is an aromatic heterocycle containing nitrogen, make this compound highly reactive, especially in the presence of electrophiles. The boron atom, which is electron-deficient, can interact with a wide range of nucleophiles, making diethyl(3-pyridyl)borane a valuable tool for organic synthesis.

One of the primary applications of diethyl(3-pyridyl)borane is in the field of catalysis. This compound is often used as a catalyst or as a ligand in catalytic processes, particularly in reactions that involve the activation of carbon-carbon bonds. It has been found to be effective in facilitating cross-coupling reactions, such as the Suzuki-Miyaura reaction, which is widely employed in the formation of carbon-carbon bonds in the synthesis of complex organic molecules. The presence of the pyridine group enhances the stability of the borane complex and contributes to the efficient transfer of the boron moiety during these reactions.

In addition to its role in catalysis, diethyl(3-pyridyl)borane has applications in the synthesis of pharmaceuticals, agrochemicals, and advanced materials. It is used in the development of new drug candidates by enabling the construction of complex molecular frameworks. Furthermore, its ability to act as a Lewis acid has made it useful in the preparation of various functionalized materials, such as organic semiconductors and polymeric materials. The compound’s reactivity and compatibility with a wide range of functional groups also make it an attractive reagent in organic synthesis, particularly in the formation of carbon-nitrogen and carbon-oxygen bonds.

Another important application of diethyl(3-pyridyl)borane is in the field of organoboron chemistry, where it is used to develop new reagents and catalysts for a variety of chemical transformations. The ability of boron to form stable complexes with a wide range of ligands, including nitrogen-containing heterocycles like pyridine, is a key feature that drives the development of new and improved reactions for both academic and industrial purposes.

In summary, diethyl(3-pyridyl)borane is a versatile and highly reactive organoboron compound that plays a significant role in modern organic synthesis and catalysis. Its discovery has contributed to the development of efficient and selective reactions, with applications in pharmaceutical, agrochemical, and material science industries. The compound continues to be a valuable tool for researchers looking to expand the capabilities of boron chemistry in various chemical transformations.

References

2016. Four-Step Synthesis of Abiraterone Acetate from Dehydroepiandrosterone. Pharmaceutical Chemistry Journal, 50(6).
DOI: 10.1007/s11094-016-1459-1

2007. 3-(Dimethylboryl)pyridine: Synthesis, Structure, and Remarkable Steric Effects in Scrambling Reactions. The Journal of Organic Chemistry, 72(25).
DOI: 10.1021/jo7018043

2012. Pharmaceuticals. Applied Cross-Coupling Reactions, 4.
DOI: 10.1007/978-3-642-32368-3_4