Synthesis, identification and antimicrobial activity of substituted thiazolines and 1,3,4-thiadiazines from dehydroacetic acid

The reaction of thiosemicarbazones with various alpha -chloroketones in the presence of anhydrous NaOAc led to 4-thiazolines 5, 7 or 1,3,4-thiadiazines 11 in good yields. Structure elucidation was carried out by H-1, C-13, and FT-IR spectroscopy. The purity of these new products was confirmed by HRMS. A possible mechanism for the formation of 5, 7, and 11 was discussed. All the synthesized novel 4-thiazoline and 1,3,4-thiadiazine derivatives were evaluated in vitro for their antibacterial and antifungal activities against six pathogenic bacteria and a strain of yeast: Escherichia coli ATCC 25992, Pseudomonas aeruginosa ATCC 27852, Staphylococcus aureus ATCC 25923 methicillin-resistant, Staphylococcus aureus ATCC 43300 methicillin-sensitive, Micrococcus luteus ATCC 4698 Enterococcus faecalis ATCC 29212 and Candida albicans IPA (200). Some compounds exhibited relatively significant antibacterial and antifungal activities.