Great attention has been paid to cyclopropenones as they are present in many natural sources.

In an attempt to develop effective and safe antibacterial agents, we synthesized novel thiazinanones by combining the quinolone scaffold and the 1,3-thiazinan-4-one group by reaction between ((4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene)hydrazinecarbothioamides and 2,3-diphenylcycloprop-2-enone in refluxing ethanol in the presence of triethyl amine as a catalyst. The structure of the synthesized compounds was characterized by spectral data and elemental analysis, IR, MS, ¹H and ¹³C NMR spectroscopy which showed two doublet signals for CH-5 and CH-6 and four sharp singlets for the protons of thiazinane NH, CHN, quinolone NH and OH, respectively. Also, the ¹³C NMR spectrum clearly showed the presence of two quaternary carbon atoms which were assigned to thiazinanone-C-5 and C-6. All the 1,3-thiazinan-4-one/quinolone hybrids were screened for antibacterial activity. Compounds 7a, 7e and 7g showed broad spectrum antibacterial activity against most of the tested strains either G +ve or G −ve. Compound 7e is the most potent antibacterial agent against MRSA with the minimum inhibitory concentration against MRSA found to be 48 μg mL⁻¹ compared to the drug ciprofloxacin (96 μg mL⁻¹). Additionally, a molecular docking study was performed to understand the molecular interaction and binding mode of the compounds on the active site of S. aureus Murb protein. In silico docking assisted data strongly correlated with the experimental approach of antibacterial activity against MRSA.

Novel furo-imidazo[3.3.3]propellanes are synthesized via reactions of thiocarbonohydrazides with (1,3-dioxo-2,3-dihydro-1H-inden-2-ylidene)propanedinitrile in tetrahydrofuran. A rationale for these conversions involving nucleophilic addition on the dicyanomethylene carbon atom is presented. The structures of these unexpected products are confirmed by using IR, NMR, mass spectrometry and single-crystal X-ray diffraction.