Synthesis and characterisation of new chromano pyrimidines and study of antimicrobial activity

Abstract

The title compounds, (five new chromano pyrimidines) were synthesized by condensation of chalcones with guanidine hydrochloride in the presence of potassium t- butoxide and t-butanol. The synthesis involves following steps- Starting with the acylation of Resorcinol using anhydrous ZnCl2 and glacial acetic acid, which afforded Resacetophenone 1. Resacetophenone was then subjected to nuclear prenylation using isoprene in the presence of polyphosphoric acid and xylene, to form 7-hydroxy-6-acetyl 2,2′-dimethyl Chroman 2. Condensation of Chroman with various substituted benzaldehydes in the presence of alcoholic KOH furnished different chalcones 3-7. Finally, Chalcones were condensed with guanidine hydrochloride in the presence of potassium t- butoxide and t-butanol and the title compounds 8-12 were obtained. Compounds thus obtained were characterized by various spectroscopic techniques to confirm their structures. The title compounds were tested at different concentrations for their antibacterial activity against Gram-positive bacteria Bacillus subtillis and Bacillus pumilus and Gram-negative bacteria Escherichia coli and Proteus vulgaris. Antifungal activity of the title compounds was tested against Rhizopus oryzae and Aspergillus niger at different concentrations. Minimum inhibitory concentration was also determined.