Autorecycling oxidation of alcohols catalysed by pyridodipyrimidines as an NAD(P)+ model

Abstract

Two kinds of pyridodipyrimidines as new NAD-type redox catalysts, 3,7,10-trisubstituted pyrido-[2,3,-d:6,5-d′]dipyrimidine-2,4,6,8(1H,3H,7H,10H)-tetraones 6 and 3,8,10-trisubstituted pyrido[2,3-d:6,5-d′]dipyrimidine-2,4,6(3H,7H,10H)-triones 7, have been synthesized by the condensation of 6-(substituted-amino)uracils 9 and 6-(substituted-amino)-2-phenylpyrimidin-4(3H)-ones 11 with appropriate 6-chloro-5-formyluracils 12 or 2,4,6-trichloropyrimidine-5-carbaldehyde 13 in dimethyl-formamide (DMF) or acetic acid. Compounds 6 and 7 have been found to oxidize a variety of alcohols under neutral conditions (in the absence of base) to yield the corresponding carbonyl compounds, catalytically with a markedly high turnover number. The oxidation yields were promoted remarkably depending upon the presence of lipophilic substituents, particularly due to the presence of longer alkyl group at the 10-position. These catalysts are so stable that the oxidation reaction proceeds until the substrate is exhausted.