New Bis(pyrazolo5,1‐bquinazolines) and Bis(9H‐xanthenediones) Linked to Alkane Cores: One‐Pot Synthesis, Antibacterial Screening, and SAR Study

Effective one‐pot methods were used to synthesize some new alkane‐linked bis(pyrazolo5,1‐bquinazolines) and bis(9H‐xanthenediones). The first series was produced, in 80‐88% yields, via the reaction of one equivalent of the appropriate bis(aldehydes) with two equivalents of 1H‐pyrazole‐3,5‐diamine and dimedone in DMF at 150 ºC for 5‐6 h. The second series was prepared, in 82‐89% yields, via the reaction one equivalent of the appropriate bis(aldehydes) with four equivalents of dimedone in acetic acid at 120 ºC for 4‐5 h. The new products displayed a broad range of antibacterial activity against different bacterial strains. Generally, the antibacterial activity of the alkane‐linked bis(pyrazolo5,1‐bquinazoline) units is more than 2‐fold their bis(9H‐xanthenedione) analogues. The (p‐tolylthio)methyl)‐linked bis(pyrazolo5,1‐bquinazolines) demonstrate the best antibacterial activity with MIC/MBC values up to 3.3/6.6 µM.