THE INVERSE ELECTRON-DEMAND DIELS-ALDER REACTION IN POLYMER SYNTHESIS.2. SOME BIS(1,2,4-TRIAZINES) AS POTENTIAL BIS-DIENE MONOMERS

Synthetic approaches to a series of 5,5'-linked bis(1,2,4-triazines) a re described: these are potential monomers in Diels-Alder polymerisati on processes. Oxidation of bis(alpha-bromophenylacetyl) substituted ar omatic compounds with dimethyl sulfoxide, or (better) oxidation of dia cetyl- or bis-(phenylacetyl) substituted aromatic compounds with hydro gen bromide in dimethyl sulfoxide, gives the corresponding bis(1,2-dik etones) and bis(alpha-keto aldehydes); these are converted into s(meth ylsulfanyl)-5,5'-arylenebis(1,2,4-triazines) by reaction with S-methyl thiosemicarbazide. The methylsulfanyl groups may then be oxidised by s tandard methods to give the corresponding methylsulfinyl or methylsulf onyl compounds, although the oxidised products show a tendency to deco mpose on storage.