Synthesis, Thermolysis, Photolysis and Antimicrobial Evaluation of some Novel Semicarbazones and Thiosemicarbazones Derived from 3-Methyl-2- benzothiazolinone Hydrazone

REACTION of 3-methyl-2-benzothiazolinone hydrazone (1) with
...... some selected isocyanate and isothiocyanate reagents 2a−j gave
the respective semicarbazones and thiosemicarbazones 3a−j.
Thermolysis of compound 3a under reduced pressure gave
N,N`−diethylurea (4) in addition to 1,2-bis(3-methylbenzo[d]thiazol-
2(3H)-ylidene)hydrazine (5). Compound 3a was almost quantitatively
recovered upon its exposure to sunlight in methanol for 60 days.
Elementary and spectroscopic measurements (IR, 1H NMR, 13C NMR,
MS) are in good accord with the structures postulated for the new
compounds. The single crystal X-ray crystallographic analysis of 3f
was given and its data were discussed. The synthesized compounds 3aj
as well as the hydrazone 1 were screened for their antibacterial
properties against Bacillus subtilis (G+), Escherichia coli (G-),
Pseudomonas aeruginosa (G-) and Staphylococcus aureus (G+) and
for their antifungal properties against Aspergillus flavus and Candida
albicans. Some of the tested compounds showed an activity against the
four bacterial strains where their order of activity was found to be 1 >
3g > 3j > 3i > 3e > 3h > 3a. The MIC90 value of compound 1 against
P. aeruginosa was 9 mg/ml. On the other hand only compound 1
showed a significant activity against A. flavus fungal species where it
recorded an inhibition zone diameter value (16 mm/mg) which is very
near to that of the standard drug, amphotericin B (17 mm/mg).
However, the C. albicans was found to be insensitive to all of the
investigated compounds.