Simple synthesis of condensed pyran containing compounds and their antimicrobial properties.

Reaction of various fused pyran compounds with formic acid was studied. Thus, refluxing 6-aminopyrano[2,3-c]pyrazole-5-carbonitriles 3 with formic acid afforded the corresponding 3-aryl-3-(5-hydroxy-3-methyl-1H-pyrazole-4-yl)propanoic acids 4. Whereas, reaction of formic acid with 2-amino-4H-1-benzopyran-3-carbonitriles 6 gave the corresponding quinoline-2,5(1H,6H)-diones 7. The study was also extended towards many spiro compounds possessing pyran residue. The antimicrobial properties of the prepared compounds was screened.