Clavibacter michiganensis causes plant diseases and is included in the list of microorganisms subject to export control. Janthinobacterium lividum is capable of synthesizing a pigment with antagonistic potential. The purpose of the study was to evaluate the activity of J. lividum VKM B-3705D and the pigment fraction against C. michiganensis VKM Ac-1402. The results of spectrophotometric and nuclear magnetic resonance analysis showed that the pigment synthesized by the J. lividum VKM B-3705D corresponds to violacein. The J. lividum strain demonstrated potential bacteriostatic activity against C. michiganensis VKM Ac-1402 when both strains were co-cultured. Compared to the control (DMSO), the violacein solution suppressed the specific growth of Clavibacter by 57.7%. The mechanism of suppression of the growth of Clavibacter is discussed. One of the ways to suppress the growth of C. michiganensis may be the inhibition of key enzymes. Violacein inhibited the activity of adenosine triphosphatase (ATPase, EC 3.6.1.3) compared to the control (DMSO) by 23.2%. Thus, the current study of the bacteriostatic effect may be a decisive step towards the development of a plant protection product.

For the first time, arylmethylidene cyclohexanones that are non-symmetrical due to the presence of peripheral substituents were studied in 1,3-dipolar cycloaddition reactions. It is shown that the interaction with the azomethine ylide generated from sarcosine proceeds regio- and diastereoselectively, with the participation of two non-equivalent parts of the dipolarophile. Also for the first time, β-amino ketones (Mannich bases) were used as dipolarophile equivalents of unsaturated ketones. It was found that cycloaddition occurs diastereoselectively at the generated center.

Intramolecular heterocyclization of thiosemicarbazones derived from α,β-enones under acid activation of one nucleophilic center afforded previously unknown 2-(2-arylethenyl)-2,3-dihydro-1,3,4-thiadiazoles. The transformation involves the thiol tautomer of thiosemicarbazone without participation of the conjugated carbon-carbon double bond.