Persulphate Oxidation of Carboxylid Acids and Amides.
Abstract
2-Biphenylyloxyacetic acid and 2-(2'-biphenylyl)-2-methylpropanoic acids on treatment with potassium persulphate in hot aqueous solution underwent oxidative decarboxylation followed by cyclization giving good yields of the corresponding pyrans and smaller quantities of dimeric products. 2-(1-Napthyl)phenoxyacetic acid, by comparison, gave mainly dimeric products and a low yield of pyram. 2-(2'Methoxybiphenylyl)- and 2-(2'-ethoxybiphenylyl)- oxyacetic acids similarly gave low yields of pyrans. A minor product obtained from the latter acid and from 1,1'-biphenylylenedioxyacetic acid in 15.5% yield has been assigned a novel spirodiketone structure and is considered to arise by Diels-Alder addition of the first-formed benzo-2,3-dihydro-furan-3-spirocyclohexa-3', 5'-diene-2'-one. Evidence is presented that SO4 is the effective oxidant in these reactions and mechanisms are proposed to account for the formation of the products. Two further examples of the oxidative cyclization of biphenyl1-2-carboxamides with persulphate are reported in which cyclization occurs with elimination of the 2'-substituent giving principally 3,4-benzo-coumarin. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 31, 1970
- Accession Number
- AD0715756
Entities
People
- R. H. Thomson
Organizations
- University of Aberdeen