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Abstract:In vitro studies to fourteen previously synthesized chromone-tetrazoles and four novel fluorine-containing analogs were conducted against pathogenic protozoan (Entamoeba histolytica), pathogenic bacteria (Pseudomonas aeruginosa, and Staphylococcus aureus), and human fungal pathogens (Sporothrix schenckii, Candida albicans, and Candida tropicalis), which have become in a serious health problem, mainly in tropical countries.

Abstract:The spiro-regioisomers 1a and 1b were synthesized from the xanthate-type precursor 2 via a free-radical mediated spirocyclization in different proportions depending on the reaction temperature, from 1:40 at -45 °C to 1:5 at 150 °C. The maximum proportion relationship value was 1:2 at 110-125 °C. The regioselectivity was a result from the inherent stability of the involved intermediate free-radicals. The intermediate of the regioisomer 1b is a very thermodynamically stable double allyl radical and for regioisomer 1a, its intermediate is an ,,,-unsaturated carbonyl radical. The products 1a-b were fully characterized by 1 H and 13 C NMR, even by X-ray analysis because adequate crystals were obtained for both products, (1a, CCDC: 1050852) and (1b, CCDC: 1050853), respectively.