Sulfur‐Promoted Synthesis of Benzoxazoles

  • Author: European Journal of Organic Chemistry
  • Published Date: 24 June 2020
  • Source / Publisher: European Journal of Organic Chemistry/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
thumbnail image: Sulfur‐Promoted Synthesis of Benzoxazoles

Related Societies

Benzoxazoles are useful molecules in organic synthesis and medicinal chemistry due to their reactivities and bioactivities. They can be synthesized from 2-aminophenols by condensation with carboxylic acid derivatives or by oxidative coupling. The latter strategy requires using an oxidant in the presence of a catalyst. Dioxygen can be used as a green oxidant. However, it has drawbacks such as the requirement for a transition-metal catalyst, possible overoxidation, a high reaction volume and/or pressure, as well as handling difficulties due to its gaseous state. As a heavier oxygen congener, sulfur could be a cheap and versatile alternative oxidant for this transformation.


Thanh Binh Nguyen, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France, and Vietnam Academy of Science and Technology, Hanoi, Quoc Anh Ngo, Vietnam Academy of Science and Technology, and colleagues have developed a simple synthesis of benzoxazoles. The desired heterocycles were prepared by heating equimolar amounts of aldehydes with 2-aminophenols and sulfur in the presence of Na2S·5H2O as a catalyst in the presence of dimethylsulfoxide (DMSO) at 70 °C (reaction pictured below).

 

 

The protocol has a good functional group tolerance and can be used with both aromatic and aliphatic aldehydes. The desired products were obtained in moderate to good yields. The reaction avoids the downsides of similar protocols that use oxygen as the oxidant.


 

 

Article Views: 582

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


Magazine of Chemistry Europe (16 European Chemical Societies)published by Wiley-VCH