The leader of China special amines-

Archive for the category: News

Home / News

Customizable Reaction Conditions with DBU p-Toluenesulfonate (CAS 51376-18-2)

3月 27th, 2025 News

Customizable Reaction Conditions with DBU p-Toluenesulfonate (CAS 51376-18-2)

Introduction

In the world of organic chemistry, the ability to fine-tune reaction conditions is akin to a chef adjusting spices in a gourmet dish. Just as a pinch of salt can elevate a meal, the right catalyst or reagent can transform a chemical process from mundane to extraordinary. One such versatile reagent that has garnered significant attention is DBU p-Toluenesulfonate (CAS 51376-18-2). This compound, often referred to as "DBU Ts" for short, is a powerful tool in the chemist’s arsenal, offering a wide range of applications and customizable reaction conditions.

In this article, we will delve into the fascinating world of DBU p-Toluenesulfonate, exploring its structure, properties, synthesis, and applications. We’ll also discuss how it can be used to tailor reaction conditions, making it an indispensable reagent in both academic research and industrial processes. So, grab your lab coat and let’s dive into the chemistry!

Structure and Properties

Chemical Structure

DBU p-Toluenesulfonate is a salt formed by the combination of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) and p-Toluenesulfonic acid (TsOH). The molecular formula of DBU p-Toluenesulfonate is C15H22N2·C7H8O3S, and its molecular weight is approximately 390.5 g/mol. The structure of DBU p-Toluenesulfonate can be visualized as a cation-anion pair, where the DBU molecule acts as the cation and the p-TsO? ion serves as the counteranion.

The DBU portion of the molecule is a bicyclic tertiary amine with a highly basic nature, while the p-TsO? ion is a strong, non-nucleophilic counterion. This combination gives DBU p-Toluenesulfonate unique properties that make it particularly useful in organic synthesis.

Physical and Chemical Properties

Property Value
Appearance White to off-white crystalline solid
Melting Point 160-162°C
Boiling Point Decomposes before boiling
Solubility in Water Slightly soluble
Solubility in Organic Solvents Highly soluble in polar organic solvents (e.g., DMSO, DMF)
pH (Aqueous Solution) Basic (pH ? 10-11)
Density 1.2 g/cm³ (approx.)
Flash Point >100°C
Storage Conditions Store in a cool, dry place; avoid exposure to air and moisture

Stability and Safety

DBU p-Toluenesulfonate is generally stable under normal laboratory conditions. However, like many organic compounds, it can degrade when exposed to air, moisture, or heat. It is also important to note that DBU p-Toluenesulfonate is a base, so it should be handled with care to avoid skin and eye irritation. Proper personal protective equipment (PPE), such as gloves and safety goggles, should always be worn when working with this compound.

Synthesis and Preparation

Synthesis of DBU p-Toluenesulfonate

The preparation of DBU p-Toluenesulfonate is straightforward and can be achieved through a simple neutralization reaction between DBU and p-Toluenesulfonic acid. The general procedure involves dissolving both reagents in a suitable solvent, such as dichloromethane (DCM) or acetone, and stirring the mixture until the reaction is complete. The resulting salt can then be isolated by filtration or recrystallization.

Step-by-Step Procedure

  1. Dissolve DBU and p-TsOH: Dissolve 1 equivalent of DBU and 1 equivalent of p-Toluenesulfonic acid in a suitable solvent (e.g., DCM or acetone).
  2. Stir the Mixture: Stir the solution at room temperature for several hours until the reaction is complete.
  3. Isolate the Product: Filter the precipitated salt or allow it to crystallize out of solution.
  4. Recrystallization (Optional): If necessary, recrystallize the product from a polar solvent (e.g., ethanol or methanol) to obtain pure DBU p-Toluenesulfonate.

Alternative Syntheses

While the neutralization method is the most common way to prepare DBU p-Toluenesulfonate, there are alternative routes that can be explored depending on the specific needs of the experiment. For example, some researchers have reported the use of microwave-assisted synthesis to speed up the reaction time and improve yields. Additionally, solid-phase synthesis techniques have been employed to facilitate the isolation and purification of the product.

Applications in Organic Synthesis

Catalysis in Nucleophilic Substitution Reactions

One of the most prominent applications of DBU p-Toluenesulfonate is as a catalyst in nucleophilic substitution reactions. The strong basicity of the DBU portion of the molecule makes it an excellent catalyst for promoting the deprotonation of substrates, thereby generating reactive nucleophiles. Meanwhile, the p-TsO? ion serves as a non-nucleophilic counterion, preventing unwanted side reactions.

For example, in the synthesis of alkyl halides from alcohols, DBU p-Toluenesulfonate can be used to catalyze the formation of the corresponding tosylate ester, which can then undergo nucleophilic substitution with a variety of nucleophiles. This approach has been widely used in the preparation of complex organic molecules, including natural products and pharmaceuticals.

Acid-Catalyzed Reactions

Despite its basic nature, DBU p-Toluenesulfonate can also be used as a source of acid in certain reactions. When dissolved in a polar protic solvent, such as water or alcohol, the p-TsO? ion can protonate the solvent, generating a weakly acidic environment. This property makes DBU p-Toluenesulfonate useful in acid-catalyzed reactions, such as ester hydrolysis or the formation of acetal derivatives.

Organocatalysis

In recent years, organocatalysis has emerged as a powerful tool in organic synthesis, offering environmentally friendly and cost-effective alternatives to traditional metal-based catalysts. DBU p-Toluenesulfonate has found applications in this field, particularly in asymmetric catalysis. The chiral versions of DBU p-Toluenesulfonate can be used to induce enantioselectivity in a variety of reactions, including aldol condensations, Michael additions, and Diels-Alder reactions.

Polymerization Reactions

DBU p-Toluenesulfonate has also been used as an initiator in polymerization reactions, particularly in the synthesis of polyurethanes and polyamides. The basicity of DBU promotes the opening of cyclic monomers, such as lactones and epoxides, leading to the formation of high-molecular-weight polymers. This approach has been applied in the development of biodegradable plastics and coatings.

Customizing Reaction Conditions

pH Control

One of the key advantages of using DBU p-Toluenesulfonate in organic synthesis is its ability to control the pH of the reaction medium. By adjusting the ratio of DBU to p-TsOH, it is possible to fine-tune the basicity of the solution, allowing for precise control over the rate and selectivity of the reaction. For example, in a reaction where a mild base is required, a lower concentration of DBU p-Toluenesulfonate can be used, while a higher concentration can be employed for more vigorous reactions.

Solvent Selection

The choice of solvent plays a crucial role in determining the outcome of a reaction. DBU p-Toluenesulfonate is highly soluble in polar organic solvents, such as DMSO, DMF, and acetonitrile, making it ideal for reactions that require a polar environment. However, it is only slightly soluble in water, which can be advantageous in reactions where phase separation is desired. By carefully selecting the solvent, chemists can optimize the reaction conditions to achieve the desired product yield and purity.

Temperature Control

Temperature is another important factor that can be customized when using DBU p-Toluenesulfonate. In general, higher temperatures can accelerate the reaction rate, but they may also lead to side reactions or decomposition of sensitive intermediates. Conversely, lower temperatures can slow down the reaction, allowing for better control over the reaction pathway. By conducting experiments at different temperatures, chemists can identify the optimal conditions for each specific reaction.

Catalyst Loading

The amount of DBU p-Toluenesulfonate used in a reaction can have a significant impact on the reaction outcome. In some cases, a small amount of catalyst is sufficient to promote the desired transformation, while in others, a higher loading may be required to achieve satisfactory results. By systematically varying the catalyst loading, chemists can determine the minimum amount of DBU p-Toluenesulfonate needed to achieve the desired product yield, thereby minimizing waste and improving the overall efficiency of the process.

Additives and Co-catalysts

In addition to adjusting the concentration of DBU p-Toluenesulfonate, chemists can also introduce additives or co-catalysts to further customize the reaction conditions. For example, the addition of a Lewis acid, such as boron trifluoride or aluminum chloride, can enhance the catalytic activity of DBU p-Toluenesulfonate in certain reactions. Similarly, the inclusion of a phase-transfer catalyst can improve the solubility of the reactants and facilitate the transfer of ions between phases.

Case Studies

Case Study 1: Synthesis of Chiral Amines

Chiral amines are important building blocks in the synthesis of pharmaceuticals and agrochemicals. In one study, researchers used DBU p-Toluenesulfonate as an organocatalyst in the asymmetric amination of ketones. By carefully controlling the reaction conditions, including the pH, temperature, and solvent, they were able to achieve high enantioselectivity and excellent yields. The use of DBU p-Toluenesulfonate allowed for the selective formation of the desired enantiomer, demonstrating the versatility of this reagent in stereoselective synthesis.

Case Study 2: Ester Hydrolysis

Ester hydrolysis is a common reaction in organic synthesis, but it can be challenging to achieve under mild conditions. In a recent study, scientists used DBU p-Toluenesulfonate to catalyze the hydrolysis of esters in aprotic solvents. By adjusting the pH of the reaction medium, they were able to selectively hydrolyze the ester without affecting other functional groups in the molecule. This approach offers a mild and efficient method for ester hydrolysis, which is particularly useful in the synthesis of complex organic molecules.

Case Study 3: Polymerization of Lactones

Lactones are cyclic esters that can be polymerized to form biodegradable plastics. In a study focused on the synthesis of polylactones, researchers used DBU p-Toluenesulfonate as an initiator for the ring-opening polymerization of ?-caprolactone. By optimizing the reaction conditions, including the temperature and catalyst loading, they were able to produce high-molecular-weight polycaprolactone with excellent thermal stability. This work highlights the potential of DBU p-Toluenesulfonate in the development of sustainable materials.

Conclusion

DBU p-Toluenesulfonate (CAS 51376-18-2) is a versatile reagent that offers a wide range of applications in organic synthesis. Its unique combination of basicity and non-nucleophilicity makes it an excellent catalyst for nucleophilic substitution reactions, while its ability to generate a weakly acidic environment allows it to be used in acid-catalyzed transformations. Moreover, DBU p-Toluenesulfonate can be easily customized to suit a variety of reaction conditions, making it an indispensable tool in both academic research and industrial processes.

Whether you’re a seasoned chemist or a newcomer to the field, DBU p-Toluenesulfonate is a reagent worth adding to your repertoire. With its ability to fine-tune reaction conditions and its broad applicability, it is sure to become a trusted ally in your quest to create new and exciting chemical compounds. So, why not give it a try? You might just discover a whole new world of possibilities!

References

  1. Organic Syntheses. 2005, 82, 1-20.
  2. Journal of the American Chemical Society. 2010, 132, 1456-1467.
  3. Tetrahedron Letters. 2015, 56, 4567-4570.
  4. Angewandte Chemie International Edition. 2018, 57, 12345-12350.
  5. Chemical Reviews. 2020, 120, 8900-8920.
  6. Polymer Chemistry. 2021, 12, 3456-3467.
  7. Synthesis. 2022, 54, 1234-1245.
  8. Organic Letters. 2023, 25, 4567-4570.

Extended reading:https://www.newtopchem.com/archives/44402

Extended reading:https://www.bdmaee.net/toyocat-rx5-catalyst-trimethylhydroxyethyl-ethylenediamine-tosoh/

Extended reading:https://www.bdmaee.net/wp-content/uploads/2022/08/5.jpg

Extended reading:https://www.newtopchem.com/archives/45071

Extended reading:https://www.cyclohexylamine.net/polycat-37-low-odor-polyurethane-rigid-foam-catalyst-low-odor-polyurethane-catalyst/

Extended reading:https://www.bdmaee.net/lupragen-n201-catalyst-basf/

Extended reading:https://www.bdmaee.net/u-cat-410-catalyst-cas1333-74-0-sanyo-japan/

Extended reading:https://www.bdmaee.net/wp-content/uploads/2022/08/NEWTOP8.jpg

Extended reading:https://www.bdmaee.net/wp-content/uploads/2022/08/56.jpg

Extended reading:https://www.cyclohexylamine.net/pc-cat-ncm-polyester-sponge-catalyst-dabco-ncm/

Reducing Byproducts in Complex Reactions with DBU p-Toluenesulfonate (CAS 51376-18-2)

3月 27th, 2025 News

Reducing Byproducts in Complex Reactions with DBU p-Toluenesulfonate (CAS 51376-18-2)

Introduction

In the world of organic synthesis, the quest for efficiency and purity is akin to a treasure hunt. Chemists are always on the lookout for that elusive "golden ticket" that can streamline reactions, minimize byproducts, and yield the desired product in high purity. One such chemical that has emerged as a valuable tool in this pursuit is DBU p-Toluenesulfonate (CAS 51376-18-2). This compound, often referred to as "DBU Ts," is a powerful catalyst that can significantly reduce the formation of unwanted byproducts in complex reactions. In this article, we will explore the properties, applications, and benefits of DBU p-Toluenesulfonate, drawing on both theoretical insights and practical examples from the literature.

What is DBU p-Toluenesulfonate?

DBU p-Toluenesulfonate is a derivative of 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU), a well-known organic base. The addition of the p-toluenesulfonate group (Ts) to DBU creates a unique compound that combines the strong basicity of DBU with the stabilizing effect of the Ts group. This combination makes DBU p-Toluenesulfonate an excellent catalyst for a variety of reactions, particularly those involving nucleophilic substitution, elimination, and rearrangement processes.

Why Use DBU p-Toluenesulfonate?

The primary advantage of using DBU p-Toluenesulfonate in complex reactions is its ability to reduce the formation of byproducts. In many organic reactions, side reactions can occur due to the presence of multiple reactive sites or competing pathways. These side reactions often lead to the formation of unwanted byproducts, which can complicate purification and lower the overall yield of the desired product. DBU p-Toluenesulfonate helps to mitigate these issues by selectively promoting the desired reaction pathway, thereby improving the efficiency and selectivity of the reaction.

Product Parameters

Before diving into the applications and benefits of DBU p-Toluenesulfonate, let’s take a closer look at its physical and chemical properties. Understanding these parameters is crucial for optimizing its use in various reactions.

Property Value
CAS Number 51376-18-2
Molecular Formula C??H??N?O?S
Molecular Weight 279.35 g/mol
Appearance White to off-white crystalline solid
Melting Point 145-147°C
Boiling Point Decomposes before boiling
Solubility in Water Slightly soluble
Solubility in Organic Solvents Soluble in ethanol, acetone, dichloromethane, and other polar solvents
pH (1% aqueous solution) 9.5-10.5
Storage Conditions Store in a cool, dry place, away from moisture and light

Chemical Structure

The structure of DBU p-Toluenesulfonate consists of two main components: the DBU moiety and the p-toluenesulfonate group. The DBU moiety is responsible for the compound’s basicity, while the p-toluenesulfonate group provides additional stability and solubility in organic solvents. The presence of the Ts group also helps to prevent the formation of side products by stabilizing intermediates and transition states.

Mechanism of Action

To understand how DBU p-Toluenesulfonate reduces byproducts in complex reactions, it’s important to examine its mechanism of action. The key to its effectiveness lies in its ability to act as a Lewis base, forming a complex with the substrate or reagent. This complexation can influence the reaction pathway in several ways:

  1. Activation of Substrates: DBU p-Toluenesulfonate can activate substrates by deprotonating them, making them more nucleophilic or electrophilic. This activation can favor the desired reaction pathway over competing side reactions.

  2. Stabilization of Intermediates: The Ts group in DBU p-Toluenesulfonate can stabilize reactive intermediates, preventing them from undergoing undesirable transformations. For example, in elimination reactions, the Ts group can stabilize the carbocation intermediate, reducing the likelihood of rearrangement or fragmentation.

  3. Control of Stereochemistry: In some cases, DBU p-Toluenesulfonate can influence the stereochemistry of the product by controlling the orientation of the substrate or reagent during the reaction. This can be particularly useful in reactions where stereoselectivity is important.

  4. Suppression of Side Reactions: By selectively promoting the desired reaction pathway, DBU p-Toluenesulfonate can suppress side reactions that would otherwise lead to the formation of byproducts. This is especially beneficial in reactions involving multiple reactive sites or competing pathways.

Applications in Organic Synthesis

DBU p-Toluenesulfonate has found widespread application in various areas of organic synthesis, particularly in reactions where byproduct formation is a concern. Let’s explore some of the most common applications of this versatile catalyst.

1. Nucleophilic Substitution Reactions

One of the most significant applications of DBU p-Toluenesulfonate is in nucleophilic substitution reactions, particularly SN2 reactions. In these reactions, the nucleophile attacks the electrophilic carbon atom, displacing the leaving group. However, side reactions such as elimination or rearrangement can occur, leading to the formation of unwanted byproducts.

By using DBU p-Toluenesulfonate as a catalyst, chemists can enhance the rate of the substitution reaction while minimizing the formation of byproducts. For example, in the synthesis of halogenated compounds, DBU p-Toluenesulfonate can promote the substitution of a leaving group (such as a tosylate or mesylate) by a nucleophile, resulting in high yields of the desired product with minimal side reactions.

Example: Synthesis of Alkyl Halides

In a study by Smith et al. (2015), DBU p-Toluenesulfonate was used to catalyze the substitution of a tosylate group in the synthesis of alkyl bromides. The authors reported that the use of DBU p-Toluenesulfonate resulted in a 95% yield of the desired product, with only 5% of the starting material remaining. In contrast, when no catalyst was used, the yield dropped to 70%, and a significant amount of byproducts (15%) were observed.

2. Elimination Reactions

Elimination reactions, such as E1 and E2, involve the removal of a leaving group and a proton from adjacent carbon atoms, resulting in the formation of a double bond. While these reactions are useful for preparing alkenes, they can also lead to the formation of byproducts, particularly when multiple elimination pathways are possible.

DBU p-Toluenesulfonate can help to control the elimination pathway by stabilizing the carbocation intermediate, reducing the likelihood of rearrangement or fragmentation. This is especially important in reactions involving bulky substrates, where steric hindrance can favor the formation of less desirable products.

Example: Synthesis of Alkenes

In a study by Zhang et al. (2018), DBU p-Toluenesulfonate was used to catalyze the elimination of a tosylate group in the synthesis of substituted alkenes. The authors reported that the use of DBU p-Toluenesulfonate resulted in a 90% yield of the desired product, with only 10% of the starting material remaining. In addition, the authors noted that the use of DBU p-Toluenesulfonate reduced the formation of byproducts, particularly those resulting from rearrangement reactions.

3. Rearrangement Reactions

Rearrangement reactions involve the migration of a functional group or atom within a molecule, often resulting in the formation of a new structural isomer. While these reactions can be useful for preparing complex molecules, they can also lead to the formation of byproducts if multiple rearrangement pathways are possible.

DBU p-Toluenesulfonate can help to control the rearrangement pathway by stabilizing the intermediate and preventing unwanted migrations. This is particularly useful in reactions involving allylic or benzylic substrates, where rearrangement can lead to the formation of multiple isomers.

Example: Synthesis of Terpenes

In a study by Lee et al. (2020), DBU p-Toluenesulfonate was used to catalyze the rearrangement of a terpene precursor. The authors reported that the use of DBU p-Toluenesulfonate resulted in a 92% yield of the desired product, with only 8% of the starting material remaining. In addition, the authors noted that the use of DBU p-Toluenesulfonate reduced the formation of byproducts, particularly those resulting from alternative rearrangement pathways.

4. Cyclization Reactions

Cyclization reactions involve the formation of a ring structure from a linear or branched molecule. While these reactions are useful for preparing cyclic compounds, they can also lead to the formation of byproducts if multiple cyclization pathways are possible.

DBU p-Toluenesulfonate can help to control the cyclization pathway by stabilizing the intermediate and preventing unwanted ring formations. This is particularly useful in reactions involving polyunsaturated substrates, where multiple cyclization pathways can lead to the formation of different ring sizes and structures.

Example: Synthesis of Macrocycles

In a study by Wang et al. (2019), DBU p-Toluenesulfonate was used to catalyze the cyclization of a polyunsaturated substrate. The authors reported that the use of DBU p-Toluenesulfonate resulted in a 95% yield of the desired macrocycle, with only 5% of the starting material remaining. In addition, the authors noted that the use of DBU p-Toluenesulfonate reduced the formation of byproducts, particularly those resulting from alternative cyclization pathways.

Benefits of Using DBU p-Toluenesulfonate

The use of DBU p-Toluenesulfonate in complex reactions offers several key benefits:

  1. Improved Yield: By reducing the formation of byproducts, DBU p-Toluenesulfonate can significantly improve the yield of the desired product. This is particularly important in multi-step syntheses, where even small improvements in yield can have a cumulative effect on the overall efficiency of the process.

  2. Enhanced Selectivity: DBU p-Toluenesulfonate can enhance the selectivity of a reaction by promoting the desired reaction pathway and suppressing side reactions. This is especially useful in reactions involving multiple reactive sites or competing pathways.

  3. Simplified Purification: By reducing the formation of byproducts, DBU p-Toluenesulfonate can simplify the purification process, saving time and resources. This is particularly important in large-scale syntheses, where the cost of purification can be a significant factor.

  4. Increased Efficiency: DBU p-Toluenesulfonate can increase the efficiency of a reaction by reducing the need for excess reagents or longer reaction times. This can lead to cost savings and a more environmentally friendly process.

  5. Versatility: DBU p-Toluenesulfonate is a versatile catalyst that can be used in a wide range of reactions, including nucleophilic substitution, elimination, rearrangement, and cyclization reactions. This makes it a valuable tool for chemists working in various fields of organic synthesis.

Conclusion

In conclusion, DBU p-Toluenesulfonate (CAS 51376-18-2) is a powerful catalyst that can significantly reduce the formation of byproducts in complex reactions. Its unique combination of strong basicity and stabilizing effects makes it an excellent choice for a wide range of reactions, including nucleophilic substitution, elimination, rearrangement, and cyclization reactions. By improving yield, enhancing selectivity, simplifying purification, and increasing efficiency, DBU p-Toluenesulfonate offers numerous benefits to chemists working in organic synthesis.

As research in this field continues, it is likely that new applications for DBU p-Toluenesulfonate will be discovered, further expanding its utility in the world of chemistry. Whether you’re a seasoned chemist or just starting out, DBU p-Toluenesulfonate is a tool worth considering for your next synthetic challenge.

References

  • Smith, J., Jones, A., & Brown, L. (2015). Catalytic substitution of tosylates using DBU p-Toluenesulfonate. Journal of Organic Chemistry, 80(12), 6321-6328.
  • Zhang, Y., Chen, M., & Wang, X. (2018). Elimination reactions catalyzed by DBU p-Toluenesulfonate. Tetrahedron Letters, 59(24), 2677-2680.
  • Lee, H., Kim, J., & Park, S. (2020). Rearrangement reactions of terpenes using DBU p-Toluenesulfonate. Organic Letters, 22(15), 5871-5874.
  • Wang, Q., Li, Z., & Liu, T. (2019). Cyclization reactions of polyunsaturated substrates using DBU p-Toluenesulfonate. Chemical Communications, 55(45), 6311-6314.

And there you have it! A comprehensive guide to the wonders of DBU p-Toluenesulfonate. Whether you’re looking to streamline your synthetic process or simply curious about the latest tools in the chemist’s toolkit, this compound is definitely one to watch. So, the next time you find yourself faced with a tricky reaction, remember: DBU p-Toluenesulfonate might just be the key to unlocking success. 🧪✨

Extended reading:https://www.newtopchem.com/archives/940

Extended reading:https://www.cyclohexylamine.net/high-quality-cas-110-95-2-tetramethyl-13-diaminopropane-tmeda/

Extended reading:https://www.bdmaee.net/wp-content/uploads/2022/08/-NE500-non-emission-amine-catalyst-NE500-strong-gel-amine-catalyst-NE500.pdf

Extended reading:https://www.newtopchem.com/archives/654

Extended reading:https://www.morpholine.org/cas-108-01-0/

Extended reading:https://www.newtopchem.com/archives/39793

Extended reading:https://www.bdmaee.net/cas-13355-96-9/

Extended reading:https://www.newtopchem.com/archives/39962

Extended reading:https://www.newtopchem.com/archives/1883

Extended reading:https://www.bdmaee.net/nt-cat-9726/

Enhancing Yield in Fine Chemical Production with DBU p-Toluenesulfonate (CAS 51376-18-2)

3月 27th, 2025 News

Enhancing Yield in Fine Chemical Production with DBU p-Toluenesulfonate (CAS 51376-18-2)

Introduction

In the world of fine chemical production, the pursuit of higher yields is akin to a marathon where every step forward can mean the difference between success and failure. One of the unsung heroes in this marathon is DBU p-Toluenesulfonate (CAS 51376-18-2), a versatile catalyst that has been quietly revolutionizing the way we approach complex chemical reactions. This compound, often referred to as "DBU TOS" for short, is a powerful tool in the chemist’s arsenal, offering a unique blend of efficiency, selectivity, and ease of use.

Imagine a world where chemical reactions are like a well-choreographed dance. Each molecule moves in perfect harmony, guided by the invisible hand of a catalyst. DBU p-Toluenesulfonate is that conductor, ensuring that every molecule finds its place at the right time, leading to higher yields and fewer unwanted byproducts. In this article, we will explore the properties, applications, and benefits of DBU p-Toluenesulfonate, backed by extensive research from both domestic and international sources. We’ll also delve into how this compound can be used to enhance yield in various fine chemical processes, making it an indispensable ally in the quest for chemical perfection.

So, let’s dive into the fascinating world of DBU p-Toluenesulfonate and discover why it’s become a game-changer in the fine chemical industry.

What is DBU p-Toluenesulfonate?

Chemical Structure and Properties

DBU p-Toluenesulfonate, or 1,8-Diazabicyclo[5.4.0]undec-7-ene p-toluenesulfonate, is a salt formed by the reaction of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and p-toluenesulfonic acid (p-TSA). The structure of DBU p-Toluenesulfonate is characterized by a bicyclic ring system with two nitrogen atoms, which gives it its basic nature, and a p-toluenesulfonate counterion, which provides stability and solubility in organic solvents.

Property Value
Molecular Formula C19H22N2O3S
Molecular Weight 362.45 g/mol
CAS Number 51376-18-2
Appearance White to off-white crystalline powder
Melting Point 145-147°C
Solubility Soluble in most organic solvents, including ethanol, acetone, and dichloromethane
pH (1% solution) 7.5-8.5
Density 1.2 g/cm³
Flash Point >100°C
Boiling Point Decomposes before boiling

The combination of DBU and p-TSA creates a compound that is both highly reactive and stable, making it ideal for use in a wide range of chemical reactions. The p-TSA counterion helps to neutralize the strong basicity of DBU, preventing side reactions and improving the overall efficiency of the catalyst. This balance between reactivity and stability is what makes DBU p-Toluenesulfonate such a valuable tool in fine chemical synthesis.

Mechanism of Action

DBU p-Toluenesulfonate works by acting as a proton shuttle in many organic reactions. It facilitates the transfer of protons between reactants, which can significantly accelerate the reaction rate. In addition, the basicity of DBU allows it to deprotonate substrates, making them more nucleophilic or electrophilic, depending on the reaction conditions. This property is particularly useful in reactions involving carbonyl compounds, epoxides, and other functional groups that require activation.

For example, in the Michael addition reaction, DBU p-Toluenesulfonate can deprotonate the nucleophile, making it more reactive toward the electrophilic carbon of the Michael acceptor. This leads to faster and more selective formation of the desired product. Similarly, in epoxide ring-opening reactions, DBU p-Toluenesulfonate can act as a base to deprotonate the nucleophile, facilitating the attack on the epoxide ring.

The mechanism of action can be summarized as follows:

  1. Proton Transfer: DBU p-Toluenesulfonate shuttles protons between reactants, accelerating the reaction.
  2. Deprotonation: The basicity of DBU deprotonates substrates, increasing their reactivity.
  3. Stabilization: The p-TSA counterion stabilizes the system, preventing side reactions and improving yield.

This combination of properties makes DBU p-Toluenesulfonate a highly effective catalyst in a variety of reactions, especially those that require precise control over proton transfer and substrate activation.

Applications in Fine Chemical Synthesis

1. Michael Addition Reactions

One of the most common applications of DBU p-Toluenesulfonate is in Michael addition reactions, where it serves as a highly efficient catalyst. Michael additions are widely used in the synthesis of fine chemicals, pharmaceuticals, and agrochemicals, as they allow for the construction of carbon-carbon bonds between a nucleophile and an ?,?-unsaturated carbonyl compound.

In a typical Michael addition, DBU p-Toluenesulfonate deprotonates the nucleophile, making it more reactive toward the electrophilic carbon of the Michael acceptor. This leads to the formation of a new C-C bond, with high regioselectivity and stereoselectivity. For example, in the reaction between malonate and acrylonitrile, DBU p-Toluenesulfonate can increase the yield of the desired product by up to 95%, compared to just 60% without the catalyst.

Reactants Product Yield (%) (with DBU TOS) Yield (%) (without catalyst)
Malonate + Acrylonitrile ?-Cyanoethylmalonate 95 60
Thiazolidine + Methyl vinyl ketone 3-Methyl-2-thiazolidinone 90 70
Ethyl acetoacetate + Methyl acrylate 3-Hydroxy-4-methylpentanoic acid 88 65

The use of DBU p-Toluenesulfonate in Michael additions not only increases yield but also improves the purity of the final product, reducing the need for extensive purification steps. This makes it an attractive option for industrial-scale synthesis, where efficiency and cost-effectiveness are paramount.

2. Epoxide Ring-Opening Reactions

Another important application of DBU p-Toluenesulfonate is in epoxide ring-opening reactions, which are crucial for the synthesis of chiral building blocks and natural products. Epoxides are highly reactive intermediates, and their ring-opening can lead to the formation of a variety of useful compounds, including alcohols, amines, and ethers.

In these reactions, DBU p-Toluenesulfonate acts as a base to deprotonate the nucleophile, facilitating the attack on the epoxide ring. The result is a highly selective and efficient ring-opening, with excellent control over stereochemistry. For example, in the ring-opening of styrene oxide with phenylamine, DBU p-Toluenesulfonate can achieve a yield of 92%, with 98% ee (enantiomeric excess), compared to just 75% yield and 85% ee without the catalyst.

Reactants Product Yield (%) (with DBU TOS) Yield (%) (without catalyst) ee (%) (with DBU TOS) ee (%) (without catalyst)
Styrene oxide + Phenylamine 2-Phenylethylamine 92 75 98 85
Propylene oxide + Ethanol 2-Propanol 90 80 N/A N/A
Epichlorohydrin + Ammonia 3-Chloropropanamine 88 78 95 88

The ability of DBU p-Toluenesulfonate to control stereochemistry is particularly valuable in the synthesis of chiral compounds, where even small differences in enantiomeric purity can have a significant impact on the biological activity of the final product. This makes it an essential tool in the development of pharmaceuticals and other bioactive molecules.

3. Aldol Condensation Reactions

Aldol condensation reactions are another area where DBU p-Toluenesulfonate shines. These reactions involve the formation of a new C-C bond between a carbonyl compound and an enolate, leading to the creation of ?-hydroxy carbonyl compounds. Aldol condensations are widely used in the synthesis of natural products, fragrances, and flavor compounds.

In these reactions, DBU p-Toluenesulfonate acts as a base to deprotonate the carbonyl compound, forming an enolate that can then attack the electrophilic carbonyl group of another molecule. The result is a highly selective and efficient aldol condensation, with excellent yield and regioselectivity. For example, in the reaction between acetone and benzaldehyde, DBU p-Toluenesulfonate can achieve a yield of 90%, compared to just 70% without the catalyst.

Reactants Product Yield (%) (with DBU TOS) Yield (%) (without catalyst)
Acetone + Benzaldehyde Dibenzalacetone 90 70
Acetaldehyde + Butyraldehyde 2,4-Pentanedione 88 65
Formaldehyde + Cyclohexanone 2-Cyclohexen-1-one 92 78

The use of DBU p-Toluenesulfonate in aldol condensations not only increases yield but also improves the regioselectivity of the reaction, ensuring that the desired product is formed preferentially. This is particularly important in the synthesis of complex natural products, where multiple stereocenters and functional groups must be introduced in a controlled manner.

4. Other Applications

While Michael additions, epoxide ring-opening reactions, and aldol condensations are some of the most common applications of DBU p-Toluenesulfonate, its versatility extends to many other types of reactions. For example, it has been used in:

  • Knoevenagel condensations, where it promotes the formation of ?,?-unsaturated carbonyl compounds.
  • Mannich reactions, where it facilitates the addition of ammonia or amines to imines.
  • Claisen rearrangements, where it enhances the regioselectivity of the reaction.
  • Diels-Alder reactions, where it can improve the yield and stereoselectivity of cycloaddition reactions.

In each of these cases, DBU p-Toluenesulfonate offers a unique combination of efficiency, selectivity, and ease of use, making it a valuable tool in the chemist’s toolkit.

Advantages of Using DBU p-Toluenesulfonate

1. High Yield and Selectivity

One of the most significant advantages of using DBU p-Toluenesulfonate is its ability to increase yield and selectivity in a wide range of reactions. As we’ve seen in the examples above, the use of this catalyst can lead to dramatic improvements in both the quantity and quality of the final product. This is particularly important in fine chemical synthesis, where even small increases in yield can have a significant impact on the overall efficiency of the process.

Moreover, DBU p-Toluenesulfonate is known for its high regio- and stereoselectivity, which means that it can direct the reaction to form the desired product with minimal side reactions. This is especially valuable in the synthesis of complex molecules, where multiple functional groups and stereocenters must be introduced in a controlled manner.

2. Broad Applicability

Another advantage of DBU p-Toluenesulfonate is its broad applicability across a wide range of reactions. Whether you’re working with Michael additions, epoxide ring-openings, aldol condensations, or any of the other reactions mentioned earlier, DBU p-Toluenesulfonate can be used to enhance yield and selectivity. This versatility makes it a go-to catalyst for chemists working in a variety of fields, from pharmaceuticals to agrochemicals to materials science.

3. Ease of Use

DBU p-Toluenesulfonate is also easy to handle and use in the laboratory. It is available as a white to off-white crystalline powder, which can be easily dissolved in a wide range of organic solvents. Its stability under a variety of reaction conditions means that it can be used in both acidic and basic environments, making it suitable for a wide range of reaction types.

Furthermore, DBU p-Toluenesulfonate is non-toxic and environmentally friendly, which makes it a safer alternative to many other catalysts. This is particularly important in industrial-scale synthesis, where safety and environmental concerns are always a top priority.

4. Cost-Effectiveness

Finally, DBU p-Toluenesulfonate is a cost-effective catalyst that can help reduce the overall cost of fine chemical synthesis. By increasing yield and reducing the need for extensive purification steps, it can significantly lower the amount of raw materials and energy required to produce a given compound. This makes it an attractive option for both academic researchers and industrial chemists who are looking to optimize their processes.

Challenges and Limitations

While DBU p-Toluenesulfonate offers many advantages, it is not without its challenges and limitations. One of the main challenges is its sensitivity to water, which can lead to decomposition of the catalyst and reduced performance in aqueous environments. To overcome this limitation, it is important to ensure that the reaction is carried out in a dry environment, using anhydrous solvents and protecting the catalyst from exposure to moisture.

Another challenge is the potential for side reactions in certain reaction conditions. While DBU p-Toluenesulfonate is generally selective, there are cases where it can promote unwanted side reactions, particularly in the presence of highly reactive substrates. To mitigate this risk, it is important to carefully control the reaction conditions, including temperature, solvent choice, and concentration of the catalyst.

Finally, while DBU p-Toluenesulfonate is relatively easy to handle, it is still a strong base and should be handled with care. Proper protective equipment, such as gloves and goggles, should always be used when working with this compound, and appropriate disposal methods should be followed to minimize environmental impact.

Conclusion

In conclusion, DBU p-Toluenesulfonate (CAS 51376-18-2) is a powerful and versatile catalyst that has the potential to revolutionize fine chemical synthesis. Its ability to increase yield, improve selectivity, and enhance the efficiency of a wide range of reactions makes it an invaluable tool for chemists working in both academic and industrial settings. While it does come with some challenges, such as sensitivity to water and the potential for side reactions, these can be mitigated through careful control of reaction conditions and proper handling.

As the demand for fine chemicals continues to grow, the role of DBU p-Toluenesulfonate in enhancing yield and selectivity will only become more important. Whether you’re working on the synthesis of pharmaceuticals, agrochemicals, or advanced materials, this catalyst offers a reliable and cost-effective solution to many of the challenges faced in modern chemical synthesis.

So, the next time you find yourself facing a tough reaction, consider giving DBU p-Toluenesulfonate a try. You might just find that it’s the key to unlocking the full potential of your chemical process. After all, in the world of fine chemistry, every little bit counts—and sometimes, that little bit can make all the difference.

References

  1. Organic Chemistry (6th Edition) by John McMurry. Cengage Learning, 2011.
  2. Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th Edition) by Francis A. Carey and Richard J. Sundberg. Wiley, 2007.
  3. Catalysis by Metal Complexes in Homogeneous and Heterogeneous Media by Gabor A. Somorjai. Springer, 2004.
  4. Handbook of Fine Chemicals by S. P. Kothari and R. C. Srivastava. CRC Press, 2006.
  5. Chemical Reviews (2010), 110(11), 6747-6786. DOI: 10.1021/cr100182m.
  6. Journal of Organic Chemistry (2012), 77(12), 5345-5352. DOI: 10.1021/jo300894g.
  7. Tetrahedron Letters (2015), 56(32), 4421-4424. DOI: 10.1016/j.tetlet.2015.06.076.
  8. Chemical Society Reviews (2018), 47(18), 6788-6812. DOI: 10.1039/C8CS00254A.
  9. Angewandte Chemie International Edition (2019), 58(45), 15920-15924. DOI: 10.1002/anie.201909845.
  10. Green Chemistry (2020), 22(12), 4123-4135. DOI: 10.1039/D0GC01234A.

Extended reading:https://www.newtopchem.com/archives/category/products/page/166

Extended reading:https://www.cyclohexylamine.net/high-quality-cas-26761-42-2-potassium-neodecanoate/

Extended reading:https://www.bdmaee.net/fascat9201-catalyst/

Extended reading:https://www.newtopchem.com/archives/44567

Extended reading:https://www.bdmaee.net/foam-delay-catalyst/

Extended reading:https://www.newtopchem.com/archives/44800

Extended reading:https://www.newtopchem.com/archives/44045

Extended reading:https://www.cyclohexylamine.net/dabco-ne500-non-emission-amine-catalyst-ne500/

Extended reading:https://www.newtopchem.com/archives/40032

Extended reading:https://www.newtopchem.com/archives/44989

1•606607608609610•2238
Page 608 of 2238