Highly efficient and diversity-oriented solvent-free synthesis of biologically active fused heterocycles using glycerol-based sulfonic acid

The present article involves preparation of some novel fused quinazoline analogs by employing aromatic aldehydes, 1,3-cyclic diketones (dimedone/cyclohexanedione) and urea/2-aminobenzothiazole, in catalytic amount of glycerol-based sulfonic acid. By employing glycerol-based sulfonic acid as a catalyst, the threat of metal contamination has been eradicated. The putative mechanism of this MCR strategy is similar to the Biginelli reaction involving Knoevenagel condensation followed by Michael addition. A series of fused derivatives confirmed the high functional group tolerance of the present protocol. The fabricated pathway has numerous advantages like high yields of desired products, green, solvent-free, and use of easily recoverable and reusable heterogeneous catalyst. Further, the anti-microbial results confirmed that among the synthesized compounds, compounds 4c and 6a were found more active as compared to ciprofloxacin against tested bacterial strains. Compounds 4g and 6a were found more active against tested fungal strains as compared to fluconazole. [GRAPHICS] .

Automated summary

This study successfully synthesized a series of novel fused quinazoline analogs using glycerol-based sulfonic acid as a catalyst. The fabricated pathway has advantages of high yields, environmentally friendly and solvent-free conditions, and easily recoverable and reusable catalyst. Some of the synthesized compounds exhibited strong antibacterial and antifungal activities.