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What is benzenethiol used for?

What is benzenethiol used for?

Science News

Unlocking Complex Sulfur Molecules: A Novel Approach for Synthesis of Functionalized Benzenethiol Equivalents

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In a groundbreaking study, researchers from Japan have developed a novel method for synthesizing o-bromobenzenethiol equivalents from readily available aryne intermediates. This advancement holds promise for various applications in pharmaceuticals, biomedical imaging, agriculture, and electronics, overcoming long-standing challenges in the synthesis of these critical organosulfur compounds.

The Importance of Organosulfur Compounds

Organosulfur compounds, which contain sulfur atoms bonded to organic molecules, play crucial roles in numerous biological processes and industrial applications. These compounds are key components in a variety of fields, including pharmaceuticals. Where they contribute to the development of essential drugs; electronics, where they are used in advanced materials. And agriculture, where they are part of eco-friendly agrochemicals. The synthesis of these compounds often relies on o-bromobenzenethiols due to their high reactivity and versatility.

Challenges with Conventional Methods

Traditional methods for producing o-bromobenzenethiols typically involve the addition of bromine to aniline, followed by the incorporation of sulfur through diazonium intermediates. However, these methods present several challenges:

  1. Selective Addition: Achieving selective bromine addition at the ortho position is difficult.
  2. Chemical Group Compatibility: Working with certain chemical groups can be problematic.
  3. Oxidation Issues: o-Bromobenzenethiols are prone to oxidation in air, leading to stability issues and the release of unpleasant odors.

A New Approach Using Aryne Intermediates

Recently, scientists have explored the use of aryne intermediates for synthesizing complex aromatic compounds. Despite their potential, controlling the addition of bromine and thiol groups to aryne intermediates has been challenging due to the strong reactivity of sulfur-containing compounds with arynes.

Breakthrough by Tokyo University of Science

Addressing these challenges, Associate Professor Suguru Yoshida and Mr. Shinya Tabata from the Tokyo University of Science have developed a novel synthesis method. They utilized potassium xanthate, a hydrogen sulfide equivalent with better reactivity in aryne reactions, along with pentafluorophenyl bromide as an electrophilic brominating reagent. This combination enabled the efficient production of o-bromobenzenethiol equivalents known as aryl xanthates.

Prof. Yoshida explained, “We developed a method for synthesizing stable o-bromobenzenethiol equivalents by bromothiolation of aryne intermediates. This approach controls the reactivity at the sulfur atom, preventing unwanted reactions with aryne intermediates.” Their findings were published online on April 30, 2024, and in Volume 26, Issue 18 of the journal Organic Letters on May 10, 2024.

Advantages of the New Method

The new method offers several significant advantages:

  1. Efficiency: The use of aryl xanthates allows for the synthesis of highly functionalized organosulfur compounds efficiently.
  2. Stability: The synthesized compounds exhibit high stability, avoiding the foul odors associated with traditional methods.
  3. Versatility: The method demonstrates good tolerance for various chemical groups, making it suitable for a wide range of applications.

Potential Applications

This innovative approach enables the synthesis of a variety of complex organosulfur compounds with fused skeletons. It also holds the potential to simplify the synthesis process for multi-substituted organosulfurs, contributing to advancements in drug discovery and other fields.

Prof. Yoshida emphasized the broader implications of their work: “Our method can enable the development of novel organosulfur compounds that could lead to new drugs, eco-friendly agrochemicals, advanced materials, and organic electronics.”

Future Prospects

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Scheme showing the how the Newman–Kwart rearrangement is used to convert phenols to thiophenols.

The study opens new avenues for the synthesis of organosulfur compounds, with ongoing research aimed at expanding the scope and applications of this method. Prof. Yoshida concluded with optimism, “Further studies on the synthesis of bioactive organosulfur compounds are underway in our laboratory, promising exciting developments in the near future.”

This pioneering research marks a significant step forward in the field of organosulfur chemistry, offering new tools and methods to scientists and industries worldwide.

Title of original paper: Bromothiolation of Arynes for the Synthesis of 2-Bromobenzenethiol Equivalents

Journal: Organic Letters

DOI: https://doi.org/10.1021/acs.orglett.4c00944

Skeletal formula


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Skeletal formula

Thiophenol

What is benzenethiol used for?