202
S¸.G. Ku¨c¸u¨kgu¨zel et al. / European Journal of Medicinal Chemistry 37 (2002) 197–206
4. Experimental
very minimal residual DMSO in the assayed medium.
Controls were run in each assay to verify this fact.
4.1. Chemistry
3.2. In 6itro e6aluation of antimicrobial acti6ity
Benzocaine, Et2O, BzCl, ethyl and allyl isothio-
cyanates were purchased from Merck Company. All the
other chemicals used in the experiments were purchased
from Fluka. All m.p. were recorded on a Bu¨chi 530
m.p. apparatus and uncorrected. UV spectra were
recorded on a Shimadzu UV 2100S spectrophotometer
Compounds 3a–e, 4e, 4f, 5a–c, 6a–c and 7a–e were
screened in vitro for their antimicrobial activity against
Acinobacter baumanii (18 strains), A. calcoaceticus (12
strains), A. lwoffii (five strains), A. johnsonii (three
strains), Agrobacterium tumefaciens (10 strains), A. ra-
diobacter (eight strains), A. rubi (four strains), Alcalige-
nes xylosoxydans (2 starins), A. faecalis (two strains),
Bacillus anthracis (two strains), B. amyloeiquefaciens
(six strains), Bacillus anthracis (two strains), B. bre6is
(13 strains), B. cereus (15 strains), B. licheriformis (eight
strains), B. magaterium (three strains), B. popiliae (one
strain), B. subtilis (38 strains), Bre6ibacillus agrii (four
strains), Burkholdria cepecia (15 strains), B. gladioli
(three strains), Cla6ibacter michiganese (two strains),
Curtobacterium flaccumfaciens (one strain), Enterobac-
ter aerogenes (eight strains), E. cloacae (two strains),
Erwinia caroto6ora (three strains), Escherichia coli (21
strains), Edwardsiella spp (four strains), Fla6obacterium
blastinum (four strains), Klebsiella pneumoniae (three
strains), K. oxytoca (14 strains), Neisseria spp (seven
strains), Pantonea agglomerans (18 strains), Pseu-
domonas aeruginosa (18 strains), P. syringae p6s. (52
strains), Proteus mirabilis (seven strains), Serratia lique-
faciens (five strains), Staphylococcus aureus (80 strains),
S. epidermis (43 strains), Stenotrophomonas maltophilia
(46 strains), Streptococcus pneumoniae (10 strains), S.
pyogenes (41 strains), Xanthomonas campestris p6s. (41
strains) for bactericidal and bacteriostatic effects, Al-
ternaria alternata (10 strains), Aspergillus niger (10
strains), Fusarium graminearum (10 strains), Microspo-
rum canis (two strains), Penicillum spp. (10 strains),
Trichoderma spp. (10 strains), Rhizoctonia solani (10
strains), Trichophyton spp. (two strains) at 1 and 0.5 mg
mL−1 using disc-diffusion method [31]. Penicillin, Ce-
faclor, Ceftizoxime, Isepamisin, Clindamycin, Ery-
thromycin, Vancomycin, Teicoplanin, Imipenem,
Meropenem, Ampicillin-sulbactam, Levofloksasin for
gram (+) bacteria and Isepamisin, Amikacin,
Netilmicin, Ceftriaxone, Cefoperazone, Cefepime, Cef-
tizoxime, Trimethoprim-Sulphametoxazol, Imipenem,
Meropenem, Aztreonam, Ampicillin, Ofloxacin for
gram (−) bacteria were used as standards in the tests.
All compounds were found inactive against tested bac-
teria and fungi, whereas 3a and 7a showed varying
degrees of inhibition against several bacteria and fungi.
Compound 3a is more active against gram (+) than
gram (−) bacteria and has a better antibacterial acti-
vity than compound 7a. The results of antimicrobial
activity are given in Tables 4 and 5.
1
(1 mg/100 mL in EtOH). H-NMR spectra were ob-
tained on a Bruker AVANC-DPX 400 instrument. Ele-
mental analyses were performed on a Carlo Erba 1106
instrument and the results were in acceptable range.
4.1.1. Preparation of ethyl
4-(4-methoxybenzoylamino)benzoate (1) and
4-(4-methoxybenzoylamino)benzoyl hydrazine (2)
These compounds were prepared according to the
method described by Rollas et al. [24].
4.1.2. Synthesis of N1-[4-(4-methoxybenzamido)-
benzoyl]-N2-substituted alkylidene hydrazines (3a–e)
and 1-[4-(4-methoxybenzamido)-benzoyl]-4-substituted
phenylthiosemicarbazides (4a–f)
A solution of 0.01 mol of 4-(4-methoxybenzoy-
lamino)benzoyl hydrazine (2) and equimolar amount of
appropriate aldehyde (for 3a–e)/appropriate isothio-
cyanate (for 4a–f) in 100 mL of EtOH was heated
under reflux for 2 h. The precipitate obtained was
filtered-off, washed with water and cleaned twice with
boiling EtOH. Physical and spectral data of 3a–e and
4e, 4f are given in Table 1. Compounds 4a–d were
previously described [24] [4a (R=ꢀCH3) m.p. 234–
235 °C, lit. [24] 227–230 °C; 4b (R=ꢀC2H5) m.p. 230,
lit. [24] 231 °C; 4c (R=ꢀCH2ꢀCHꢁCH2) m.p. 218, lit.
[24] 216–218 °C and 4d (R=ꢀC6H5) m.p. 249–
250 °C, lit. [24] 250 °C].
4.1.3. Synthesis of 2-[4-(4-methoxybenzoylamino)-
benzoylhydrazono]-3-alkyl-4-thiazolidinones (5a–c)
0.01 mol of appropriate thiosemicarbazide 4a–c and
0.011 mol of ethyl bromoacetate were refluxed in 30 mL
of absolute EtOH in the presence of 0.04 mol of
anhydrous NaOAc for 9 h. The reaction mixture was
cooled, diluted with water and allowed to stand
overnight. The solid precipitated was washed with wa-
ter, dried and washed with hot EtOH to give 5a–c.
Analysis for 5b: R: ꢀC2H5. C20H20N4O4S. Molecular
weight: 412.40. m.p. 247–250 °C. Yield: 67%. UV
1
(EtOH) umax (nm) (log m): 296 (4.70), 223 (4.24). H-
NMR (400 MHz, DMSO-d6), ppm: 1.11 (t, 3H,
CH3ꢀCH2ꢀ); 3.67 (q, 2H, CH3ꢀCH2ꢀ); 3.76 (s, 3H,
ꢀOꢀCH3); 3.95 (s, 2H, ꢀSꢀCH2); 6.99–7.89 (m, 8H,
ArꢀH); 10.19 (s, 1H, N1ꢀH); 10.63 (s, 1H, N2ꢀH).
13C-NMR (100.6 MHz, DMSO-d6), ppm: 13.02