Sodium Triacetoxyborohydride: || 56553-60-7 || manufacturer || india

Chemical Name: Sodium Triacetoxyborohydride
Molecular Formula: C6H10BNaO6
CAS Number: 56553-60-7
Molecular Weight: 211.94 g/mol
IUPAC Name: Sodium triacetoxyborohydride
Appearance: White to off-white crystalline powder
Solubility: Soluble in acetonitrile, dichloromethane, THF; decomposes in water
Melting Point: ~120-122°C (with decomposition)

Description

Sodium Triacetoxyborohydride (STAB) is a highly selective reducing agent widely used in organic synthesis, particularly in reductive amination reactions. It is an acyloxy borohydride that offers superior selectivity compared to sodium cyanoborohydride, especially in the reductive amination of aldehydes and ketones with primary or secondary amines. Its mild reaction conditions make it a reagent of choice for sensitive substrates that require careful control during reduction processes.

Sodium Triacetoxyborohydride is often preferred in synthetic chemistry due to its lower toxicity compared to cyanoborohydride and its ease of handling under non-aqueous conditions. The reagent is stable in alcohols and aprotic solvents, and it does not require the presence of a proton source for effective reduction. It is especially useful for reducing imines and iminium ions, which are intermediate species in reductive amination reactions.

Table of Contents

1. General Information

Sodium Triacetoxyborohydride is a versatile reducing agent employed primarily in reductive amination reactions in organic chemistry. It is prized for its selective reduction properties, especially in the presence of aldehydes or ketones, where it facilitates the formation of amines without over-reduction of the carbonyl groups to alcohols. Its mild reaction conditions and high selectivity make it a preferred reagent in drug discovery, fine chemical production, and other fields of synthetic organic chemistry.

2. Chemical Properties

• Molecular Formula: C6H10BNaO6
• Molecular Weight: 211.94 g/mol
• CAS Number: 56553-60-7
• Melting Point: 120-122°C (with decomposition)
• Appearance: White to off-white crystalline powder
• Solubility: Soluble in organic solvents such as acetonitrile, dichloromethane, and tetrahydrofuran (THF); decomposes in water.

The stability of Sodium Triacetoxyborohydride in organic solvents and its decomposition in water makes it ideal for non-aqueous synthetic reactions.

3. Applications

Sodium Triacetoxyborohydride is extensively used in:

• Reductive Amination: One of the primary applications of Sodium Triacetoxyborohydride is in reductive amination, where it reduces imines or iminium ions to amines. This reaction is critical in pharmaceutical synthesis, where amines are a common functional group in many bioactive molecules.
• Selective Reduction: Its mild reducing conditions are advantageous for reducing aldehydes and ketones selectively without reducing other functional groups, such as esters or nitro groups.
• Organic Synthesis: This reagent finds use in the preparation of secondary and tertiary amines, which are important building blocks in the synthesis of complex organic molecules.

Due to its selectivity, Sodium Triacetoxyborohydride is often preferred over stronger reducing agents like sodium borohydride when working with sensitive substrates.

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4. Reaction Mechanism

The reduction mechanism of Sodium Triacetoxyborohydride involves the delivery of a hydride ion to the carbon-nitrogen double bond of an imine or iminium ion. The presence of acetoxy groups in the reagent allows for controlled hydride transfer, preventing over-reduction and ensuring that the reaction proceeds selectively.

1. Formation of Imine/Iminium Ion: In reductive amination, an aldehyde or ketone reacts with a primary or secondary amine to form an imine or iminium ion.
2. Hydride Transfer: Sodium Triacetoxyborohydride donates a hydride to the carbon-nitrogen bond of the imine/iminium intermediate, reducing it to the corresponding amine.
3. By-products: The reaction typically produces sodium acetate and boron-containing by-products, which are relatively easy to remove during purification.

5. Handling and Safety

Sodium Triacetoxyborohydride should be handled with care, as it is sensitive to moisture and decomposes in water. It is recommended to store the reagent in a tightly sealed container, away from any sources of moisture. Working in a dry, inert atmosphere, such as under nitrogen or argon, is ideal.

When handling Sodium Triacetoxyborohydride, appropriate Personal Protective Equipment (PPE) should be used, including gloves, safety goggles, and a lab coat. As it is sensitive to moisture, it should be handled in a fume hood to prevent exposure to humidity and to protect the user from inhaling any dust.

6. Safety Data

Hazard Classifications

• Irritant: Sodium Triacetoxyborohydride can cause irritation to the skin, eyes, and respiratory system upon contact or inhalation.
• Toxicity: While less hazardous than cyanoborohydride, it is still toxic if ingested or inhaled in significant quantities.

Pictograms:

• Exclamation Mark: Indicates that Sodium Triacetoxyborohydride is an irritant and should be handled with care.

Hazard Statements:

• H315: Causes skin irritation.
• H319: Causes serious eye irritation.
• H335: May cause respiratory irritation.

Precautionary Statements:

• P280: Wear protective gloves, protective clothing, and eye protection.
• P261: Avoid breathing dust/fumes.
• P305+P351+P338: If in eyes, rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do.

7. Peer-Reviewed Studies

Sodium Triacetoxyborohydride has been extensively studied in academic and industrial research. Notable areas of study include:

• Pharmaceutical Synthesis: Studies have demonstrated the reagent’s efficiency in the preparation of amine-containing drug candidates, particularly in the context of medicinal chemistry and lead optimization.
• Methodology Development: Research on improving the conditions for reductive amination and selective reduction using Sodium Triacetoxyborohydride has contributed to more efficient synthetic protocols.
• Applications in Natural Products: The reagent has been employed in the synthesis of alkaloids and other natural products, showcasing its utility in forming complex amine frameworks.

Conclusion

Sodium Triacetoxyborohydride is an essential reagent for organic chemists, particularly for its role in reductive amination and selective reductions. Its stability in organic solvents and selective reactivity make it an excellent choice for the synthesis of amines and other nitrogen-containing compounds. However, careful handling and storage are necessary to ensure safety and maintain its reactivity in the lab.