Kolomieitsev D. Heterocyclization based on thieno[2,3-d]pyrimidines

We identified reaction conditions for selective heterocyclization of 4-hydrazinocyclopenta(hexa)[4,5]thieno[2,3-d]pyrimidines with such electrophilic agents as sodium salts of methyl 4-aryl(heteryl)-2,4-dioxobutanoates. Refluxing of the starting components in acetic acid led to formation of compounds, with structures that combine triazine and thienopyrimidine rings. Interaction according to a mechanism analogous that to of Dimrot rearrangement and ring-opening driving force pre-protonated pyrimidine cycle is effective interaction nN4 sigma sigma*CN2, which ensured a parallel arrangement of the lone pair of electrons an atom N1 and sigma-bond CH-N2, through the optimal overlap of the interacting orbitals and high nucleophilicity N4 atom. Interaction of the hydrazine derivatives thieno[2,3-d]pyrimidine with maleic anhydride in refluxing acetic acid led to the formation 2-(3-oxo-3,4,9,10,11,12-hexahydro-2H-benzo[4,5]thieno[2,3:4,5]pyrimido[6,1-c][1,2,4]triazine-4-yl)acetic acid. The reaction with phthalic and nitrophthalic anhydrides proceeded similarly at the first stage. But their further heating in acetic acid led to the formation of imides. It was found that interaction of the hydrazine derivatives thieno[2,3-d]pyrimidine with electrophilic reagents such as acetyl chloride, ethyl pyruvate, benzoyl chloride and dimethyl but-2-ynedioate led to the formation the corresponding 1,2,4-triazin via an mechanism analogous to Dimroth-like rearrangement. O-containing N-alkyl derivatives of thieno[2,3-d]pyrimidine and S-(Se)-alkyl compounds were tested for the presence of antimicrobial and fungicidal activity of the compound and identified compound-leaders.