81028-81-1

Upstream product

• 527-72-0 2-thiophenylcarboxylic acid 
• 882-33-7 diphenyldisulfane 
• 16718-11-9 phenyl-(thien-3-yl)-sulphide 
• 124-38-9 carbon dioxide 

Relevant academic research and scientific papers

Ruthenium(II)-Catalyzed ortho-C-H Chalcogenation of Benzoic Acids via Weak O-Coordination: Synthesis of Chalcogenoxanthones

A general protocol for direct chalcogenation of inert C-H bonds of (hetero)aromatic carboxylic acids is developed with a ruthenium(II) catalyst using readily available starting materials, offering densely substituted ortho-chalcogenyl aromatic acids in high yields (up to 96%). The strategy avoids the installation of an external directing group, use of metallic oxidants, and features operational simplicity with ample substrate scope. Synthetic application en route to biologically important chalcogenoxanthones is also demonstrated. This work represents the first example of ruthenium(II)-catalyzed direct C-H chalcogenation of benzoic acids.

Application of Regioselective Thiophene Lithiation to the Synthesis of Thiophene Analogues of Xanthones and Thioxanthones

Treatment of 3-(p-tolyloxy)thiophene (3) with phenyllithium followed by carbonation with CO2 was found to be a convenient procedure for the preparation of the thiophene-2-carboxylic acid 4, which was cyclized to 5 with PPE.Treatment of 3 with butyllithium followed by carbonation gave the thiophene-2,5-dicarboxylic acid 8 which was cyclized to 9.Alkaline permanganate oxidation of 4 gave the diacid 10, which was cyclized to the tricyclic acid 11.Similar lithiation reactions were observed with additional 3-(aryloxy)thiophenes and with 3-(arylthio)thiophenes, and xanthone analogues were prepared from the resulting intermediates.