Synthesis, structure and biological activity of four new picolinohydrazonamide derivatives.

Four new picolinohydrazonamide derivatives, namely, 6-methyl-N'-(morpholine-4-carbonothioyl)picolinohydrazonamide, C12H17N5OS, 6-chloro-N'-(morpholine-4-carbonothioyl)picolinohydrazonamide methanol monosolvate, C11H14ClN5OS·CH3OH, 6-chloro-N'-(4-phenylpiperazine-1-carbonothioyl)picolinohydrazonamide, C17H19ClN6S, and 6-chloropicolinohydrazonamide, C6H7ClN4, have been synthesized and characterized by NMR spectroscopy and single-crystal low-temperature X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The first three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules in the structure. They also adopt the same symmetry, i.e. P21/c (P21/n), unlike the fourth structure which is chiral and has the space group P212121. For all the studied cases, intermolecular N-H...O and N-H...N hydrogen bonds play an essential role in the formation of the structures.