Synthesis and antimicrobial evaluation of some new 2-(5,6-dihydro-4H -1,2,4-triazolo[4,3-a]benz[F]azepin-1-yl)methyl-4-substituted phthalazin-1(2H )-ones

Article abstract of DOI:10.14233/ajchem.2014.17984

Starting from 4-substituted-phthalazin-1(2H)-one (1), A series of new 2-(5,6-dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-1-yl)methyl)-4-substituted phthalazin-1(2H)-ones derivatives ( 5) have been synthesized. The structure of synthesized new compounds was established by spectral data and screened for their antimicrobial activities against various bacteria and fungi strains.

Full text of DOI:10.14233/ajchem.2014.17984

Asian Journal of Chemistry; Vol. 26, No. 22 (2014), 7828-7832
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.17984
Synthesis and Antimicrobial Evaluation of Some New 2-(5,6-Dihydro-4H-1,2,4-
triazolo[4,3-a]benz[F]azepin-1-yl)methyl)-4-substituted Phthalazin-1(2H)-ones
1,*
2
3
IBRAHIM E. EL-SHAMY , A.M. ABDEL-MOHSEN , MOUSTAFA M.G. FOUDA ,
SALEM S. AL-DEYAB , AHMED ABDEL-MEGEED4,5 and MAHER A. EL-HASHASH
3
6
1Department of Chemistry, Faculty of Science, Fayoum University, Fayoum, Egypt
2Central European Institute of Technology (CEITEC), Brno University of Technology, Brno, Czech Republic
3Petrochemical Research Chair, Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
4Plant Protection Department, Faculty of Agriculture, (Saba Basha), Alexandria University, Alexandria, Egypt
5Botany and Microbiology Department, College of Science, King Saud University, P.O. Box 2455-Riyadh 11451, Saudi Arabia
6Department of Chemistry, Faculty of Science, Ain Shams University, Cairo, Egypt
*Corresponding author: E-mail: iei00@fayoum.edu.eg
Received: 10 May 2014;
Accepted: 4 July 2014;
Published online: 6 November 2014;
AJC-16244
Starting from 4-substituted-phthalazin-1(2H)-one (1), A series of new 2-(5,6-dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-1-yl)methyl)-
4-substituted phthalazin-1(2H)-ones derivatives (5) have been synthesized. The structure of synthesized new compounds was established
by spectral data and screened for their antimicrobial activities against various bacteria and fungi strains.
Keywords: Triazole derivatives, Phthalazin, Antibacterial activity.
to synthesize new phthalazinone derivatives with the aim to
evaluate their antimicrobial activities.
INTRODUCTION
Nitrogen-containing heterocyclic compounds are wide-
spread in nature and their applications to biologically active
pharmaceuticals, agrochemicals and functional materials are
becoming more and more important1. Phthalazin-1(2H)-ones
are important building blocks in the construction of new mole-
cular systems for biologically active molecules2-4. The develop-
ment of new and efficient methodologies for synthesis of poten-
tially bioactive phthalazin-1(2H)-one derivatives is important.
Phthalazin-1(2H)-ones are of considerable interest due to their
antidiabetic5, antiallergic6, Vasorelaxant7, PDE4 inhibitors8,
VEGF (vascular endothelial growth factor) receptor tyrosine
kinases for the treatment of cancer9,10, antiasthmatic agents
with dual activities of thromboxane A2 (TXA2) synthetase
inhibition and bronchodialation11, herbicidal12, like activities.
EXPERIMENTAL
Melting points were determined on a MEL-TEMP II melting
point apparatus in open glass capillaries and are uncorrected.
The infrared spectra were recorded for potassium bromide
discs on a Pye-Unicam SP1025 spectrophotometer. NMR
spectra were carried out at ambient temperature (about 25 ºC)
with a Brucker AC-250 spectrometer or with a Varian Gemini
200 spectrometer at 250 MHz using tetramethylsilane (TMS)
as an internal standard. Mass spectra (MS) were performed
on a Hewlett-Packard 5995 gas chromatography-mass spectro-
meter system or on a Shimadzu GCMS-QP 1000 EX mass
spectrometer. Homogeneity of the products and follow up of
the reactions were checked by ascending thin-layer chromato-
graphy TLC on plates precoated with silica gel G (E. Merck;
layer thickness 0.25 mm), used without pretreatment.
A number of established drug molecules like hydralazine13,14
,
budralazine15,16, azelastine17,18, ponalrestat19 and zopolrestat20
are prepared from the corresponding phthalazinones. Several
ways have been reported in the literature for the synthesis of
phthalazinones21,22. Generally, phthalazines are synthesized
from either phthalic anhydride derivatives, 2-aryl-3-hydroxy-
inden-1-ones or β-diketones via condensation with hydrazine
hydrate by either heating23 or using microwave irradiation24.
In view of the aforementioned facts, it seemed most interesting
General procedure for preparation [4-substituted-
1(2H)-oxo-phthalazin-2-yl]acetic acid ethyl ester (2a-j): A
mixture of phthalazinone 1a-j (0.01 mol), 5 g ethyl bromoacetate
(0.03 mol) and 4.1 g potassium carbonate (0.03 mol) in 30 mL
dry acetone was heated under reflux for 30 h, cooled at room
temperature and poured into water. The obtained solid was
filtered off and crystallized from appropriate solvent to give 2a-j.

Vol. 26, No. 22 (2014)
Synthesis and Antimicrobial Evaluation of Some New 4-Substituted Phthalazin-1(2H)-ones 7829
[4-Phenyl-1(2H)-oxo-phthalazin-2-yl]acetic acid ethyl
ester (2a): m.p. 101-102 ºC; yield 66.4 %; 1H NMR (DMSO-
d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr,
[4-(Biphenyl-4-yl)-1(2H)-oxo-phthalazin-2-yl]acetic
acid ethyl ester (2j): m.p. 119-120 ºC; yield 60%; 1H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 1731, 1658 (2CO); MS (70 eV) m/z
(%):384 (M+, 30). Anal. calcd. (%) for C24H20N2O3: C, 74.98;
H, 5.24; N, 7.29; found (%) C, 74.96; H, 5.26; N, 7.33.
General procedure for preparation [4-substituted-
1(2H)-oxo-phthalazin-2-yl]acetic acid hydrazide (3a-j): A
mixture of ester 2 (0.01 mol) and 2 mL hydrazine hydrate in
50 mL absolute ethanol was refluxed for 2 h and cooled at
room temperature. The resultant solid was filtered and crysta-
llized from appropriate solvent to give 3.
ν
max, cm-1): 1733, 1660 (2CO); MS (70 eV) m/z (%):308 (M+,
10). Anal. calcd. (%) for C18H16N2O3: C, 70.12; H, 5.23; N,
9.09; found (%) C, 70.19; H, 5.20; N, 9.03.
[4-(4-Methoxyphenyl)-1(2H)-oxo-phthalazin-2-
yl]acetic acid ethyl ester (2b): m.p. 111-112 ºC; yield 60 %;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 1731, 1658 (2CO); MS (70 eV)
m/z (%): 338(M+, 9).Anal. calcd. (%) for C19H18N2O4: C, 67.44;
H, 5.36; N, 8.28; found (%) C, 67.40; H, 5.39; N, 8.20.
[4-(4-Chlorophenyl)-1(2H)-oxo-phthalazin-2-yl]acetic
[4-Phenyl-1(2H)-oxo-phthalazin-2-yl]acetic acid
hydrazide (3a). m.p. 210-211 ºC; yield 71%; 1H NMR (DMSO-
d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr,
1
acid ethyl ester (2c): m.p. 99-100 ºC; yield 61%; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 1740, 1664 (2CO); MS (70 eV) m/z (%):
342(M+, 12). Anal. calcd. (%) for C18H15N2O3Cl: C, 63.07; H,
4.41; Cl, 10.34; N, 8.17; found (%) C, 63.02; H, 4.45; Cl,
10.30; N, 8.14.
ν
max, cm-1): 3451, 3211 (NHNH2), 1660 (CO); MS (70 eV) m/
z (%): 294(M+, 43).Anal. calcd. (%) for C16H14N4O2: C, 65.30;
H, 4.79; N, 19.04; found (%) C, 65.34; H, 4.78; N, 19.08.
[4-(4-Methoxyphenyl)-1(2H)-oxo-phthalazin-2-yl]acetic
1
[4-(3,4-Dichlorophenyl)-1(2H)-oxo-phthalazin-2-
yl]acetic acid ethyl ester (2d): m.p. 145-146 ºC; yield 70 %;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 1744, 1666 (2CO); MS (70 eV)
m/z (%):377 (M+, 10). Anal. calcd. (%) for C18H14N2O3Cl2: C,
57.31; H, 3.74; Cl, 18.80; N, 7.43; found (%) C, 57.35; H,
3.70; Cl, 18.77; N, 7.40.
acid hydrazide (3b): m.p. 235-236 ºC; yield 61%; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR
(KBr, νmax, cm-1): 3433, 3220 (NHNH2), 1663 (CO); MS (70
eV) m/z (%): 324 (M+, 10). Anal. calcd. (%) for C17H16N4O3: C,
62.95; H, 4.97; N, 17.27; found (%) C, 62.90; H, 4.99; N, 17.20.
[4-(4-Chlorophenyl)-1(2H)-oxo-phthalazin-2-yl]acetic
acid hydrazide (3c): m.p. 254-255 ºC; yield 63%; 1H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 3450, 3220 (NHNH2), 1664 (CO); MS
(70 eV) m/z (%): 328 (M+, 15). Anal. calcd. (%) for
C16H13N4O2Cl: C, 58.45; H, 3.99; Cl, 10.78; N, 17.04; found
(%) C, 58.40; H, 3.94; Cl, 10.79; N, 17.08.
[4-(4-(4-Chlorobenzyl)phenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid ethyl ester (2e): m.p. 105-106 ºC; yield 67%;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 1736, 1659 (2CO); MS (70 eV)
m/z (%):432 (M+, 18). Anal. calcd. (%) for C25H21N2O3Cl: C,
69.36; H, 4.89; Cl, 8.19; N, 6.47; found (%) C, 69.39; H, 4.93;
Cl, 8.18; N, 6.40.
[4-(3,4-Dichlorophenyl)-1(2H)-oxo-phthalazin-2-
yl]acetic acid hydrazide (3d): m.p. 260-261 ºC; yield 68%;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 3444, 3231 (NHNH2), 1667 (CO);
MS (70 eV) m/z (%): 363 (M+, 11). Anal. calcd. (%) for
C16H12N4O2Cl2: C, 52.91; H, 3.33; Cl, 19.52; N, 15.43; found
(%) C, 52.98; H, 3.30; Cl, 19.55; N, 15.40.
[4-(3-Chloro-4-methylphenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid ethyl ester (2f): m.p. 107-108 ºC; yield 65%;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 1732, 1660 (2CO); MS (70 eV)
m/z (%):356 (M+, 14). Anal. calcd. (%) for C19H17N2O3Cl: C,
63.96; H, 4.80; Cl, 9.94; N, 7.85; found (%) C, 63.90; H, 4.84;
Cl, 9.90; N, 7.81.
[4-(4-(4-Chlorobenzyl)phenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid hydrazide (3e): m.p. 244-245 ºC; yield 66%;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 3459, 3210 (NHNH2), 1661 (CO);
MS (70 eV) m/z (%):418 (M+, 10). Anal. calcd. (%) for
C23H19N4O2Cl: C, 65.95; H, 4.57; Cl, 8.46; N, 13.38; found
(%) C, 65.90; H, 4.59; Cl, 8.46; N, 13.41.
[4-Mesityl -1(2H)-oxo-phthalazin-2-yl]acetic acid ethyl
ester (2g): m.p. 124-125 ºC; yield 66%; 1H NMR (DMSO-d6)
δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax
,
cm-1): 1731, 1662 (2CO); MS (70 eV) m/z (%):350 (M+, 7).
Anal. calcd. (%) for C21H22N2O3: C, 71.98; H, 6.33; N, 7.99;
found (%) C, 71.90; H, 6.37; N, 8.03.
[4-(3-Chloro-4-methylphenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid hydrazide (3f): m.p. 271-272 ºC; yield 70%;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 3450, 3238 (NHNH2), 1658 (CO);
MS (70 eV) m/z (%):342 (M+, 12). Anal. calcd. (%) for
C17H15N4O2Cl: C, 59.57; H, 4.41; Cl, 10.34; N, 16.34; found
(%) C, 59.50; H, 4.45; Cl, 10.38; N, 16.39.
[4-(4-Benzylphenyl)-1(2H)-oxo-phthalazin-2-yl]acetic
1
acid ethyl ester (2h): m.p. 76-78 ºC; yield 71 %; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 1735, 1664 (2CO); MS (70 eV) m/z
(%):398(M+, 19). Anal. calcd. (%) for C25H22N2O3: C, 75.36;
H, 5.57; N, 7.03; found (%) C, 75.30; H, 5.62; N, 7.07.
[4-(Pyridin-4-ylmethyl)phenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid ethyl ester (2i): m.p. 117-118 ºC; yield 62 %;
1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H,
Ar-H); IR (KBr, νmax, cm-1): 1741, 1665 (2CO); MS (70 eV) m/z
(%):399 (M+, 10). Anal. calcd. (%) for C24H21N3O3: C, 72.16;
H, 5.30; N, 10.52; found (%) C, 72.10; H, 5.34; N, 10.54.
[4- Mesityl -1(2H)-oxo-phthalazin-2-yl]acetic acid
hydrazide (3g): m.p. 227-228 ºC; yield 69 %; 1H NMR (DMSO-
d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr,
ν
max, cm-1): 3466, 3219 (NHNH2), 1662 (CO); MS (70 eV) m/z
(%):336 (M+, 20). Anal. calcd. (%) for C19H20N4O2: C, 67.84;
H, 5.99; N, 16.66; found (%) C, 67.88; H, 5.94; N, 16.60.

7830 El-Shamy et al.
Asian J. Chem.
[4-(4-Benzylphenyl)-1(2H)-oxo-phthalazin-2-yl]acetic
acid hydrazide (3h): m.p. 130-132 ºC; yield 65 %; 1H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 3467, 3243 (NHNH2), 1665 (CO); MS (70
eV) m/z (%):384 (M+, 13). Anal. calcd. (%) for C23H20N4O2: C,
71.86; H, 5.24; N, 14.57; found (%) C, 71.80; H, 5.29; N, 14.53.
[4-(Pyridin-4-ylmethyl)phenyl)-1(2H)-oxo-phthalazin-
2-yl]acetic acid hydrazide (3i). m.p. 130-131 ºC; yield 62
%; 1H NMR (DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m,
14H, Ar-H); IR (KBr, νmax, cm-1): 3461, 3210 (NHNH2), 1660
(CO); MS (70 eV) m/z (%):385 (M+, 18). Anal. calcd. (%) for
C22H19N5O2: C, 68.56; H, 4.97; N, 18.17; found (%) C, 68.59;
H, 4.90; N, 18.19.
IR (KBr, νmax, cm-1): 1660 (CO); MS (70 eV) m/z (%):543(M+,
9). Anal. calcd. (%) for C33H26N5OCl: C, 72.85; H, 4.82; Cl,
6.52; N, 12.87; found (%) C, 72.80; H, 4.85; Cl, 6.50; N, 12.89.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl) methyl)-4-(3-chloro-4-methyl phenyl)phthalazin-
1
1(2H)-ones (5f): m.p. 157-158 ºC; yield 56 %; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR
(KBr, νmax, cm-1): 1665 (CO); MS (70 eV) m/z (%):467 (M+, 8).
Anal. calcd. (%) for C27H22N5OCl: C, 69.30; H, 4.74; Cl, 7.58;
N, 14.97; found (%) C, 69.39; H, 4.70; Cl, 7.57; N, 14.90.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl) methyl)-4-mesityl-phthalazin-1(2H)-ones (5g): m.p.
123-124 ºC; yield 56 %; 1H NMR (DMSO-d6) δ: 4.91 (s, 2H,
CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax, cm-1): 1663
(CO); MS (70 eV) m/z (%):461 (M+, 12). Anal. calcd. (%) for
C29H27N5O: C, 75.46; H, 5.90; N, 15.17; found (%) C, 75.49;
H, 5.93; N, 15.19.
[4-(Biphenyl-4-yl)-1(2H)-oxo-phthalazin-2-yl]acetic
acid hydrazide (3j): m.p. 250-251 ºC; yield 77 %; 1H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 3450, 3221 (NHNH2), 1660 (CO); MS
(70 eV) m/z (%):370 (M+, 29).Anal. calcd. (%) for C22H18N4O2:
C, 71.34; H, 4.90; N, 15.13; found (%) C, 71.34; H, 4.90; N,
15.13.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl) methyl)-4-(4-benzylphenyl)phthalazin-1(2H)-ones
1
(5h): m.p. 100-101 ºC; yield 61%; H NMR (DMSO-d6) δ:
General procedure for preparation 2-((5,6-dihydro-
4H-1,2,4-triazolo[4,3-a]-benz[f]azepin-1-yl) methyl)-4-
substituted-phthalazin-1(2H)-one (5a-j): A mixture of
hydrazide 3 (0.01 mol) and seven-membered lactim ether 4
(0.01 mol) in 40 mL absolute ethanol was refluxed for 5 h and
cooled at room temperature. The resultant solid was filtered
and crystallized from appropriate solvent to give 5a-j.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]-
azepin-1-yl) methyl)-4- phenyl -phthalazin-1(2H)-ones (5a):
m.p. 149-150 ºC; yield 61 %; 1H NMR (DMSO-d6) δ: 4.91 (s,
2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax, cm-1): 1660
(CO); MS (70 eV) m/z (%): 419 (M+, 19). Anal. calcd. (%) for
C26H21N5O: C, 74.44; H, 5.05; N, 16.70; found (%) C, 74.48;
H, 5.00; N, 16.73.
4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax,
cm-1): 1657 (CO); MS (70 eV) m/z (%):509 (M+, 15). Anal.
calcd. (%) for C33H27N5O: C, 77.78; H, 5.34; N, 13.74; found
(%) C, 77.81; H, 5.34; N, 13.78.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl)methyl)-4-(pyridin-4-ylmethyl)phenyl)phthalazin-
1
1(2H)-ones (5i): m.p. 144-145 ºC; yield 55 %; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 1661 (CO); MS (70 eV) m/z (%):510(M+,
14). Anal. calcd. (%) for C32H26N6O: C, 75.27; H, 5.13; N,
16.46; found (%) C, 75.20; H, 5.18; N, 16.48.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl) methyl)-4-(biphenyl-4-yl)phthalazin-1(2H)-ones (5j):
m.p. 153-154 ºC; yield 60 %; 1H NMR (DMSO-d6) δ: 4.91 (s,
2H, CH2), 7.01-8.23 (m, 14H,Ar-H); IR (KBr, νmax, cm-1): 1666
(CO); MS (70 eV) m/z (%):495 (M+, 10). Anal. calcd. (%) for
C32H25N5O: C, 77.56; H, 5.08; N, 14.13; found (%) C, 77.50;
H, 5.09; N, 14.18.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]-
azepin-1-yl) methyl)-4-(4-methoxyphenyl)phthalazin-
1
1(2H)-ones(5b): m.p. 130-131 ºC; yield 55 %; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);
IR (KBr, νmax, cm-1): 1658 (CO); MS (70 eV) m/z (%):449
(M+, 10). Anal. calcd. (%) for C27H23N5O2: C, 72.14; H, 5.16;
N, 15.58; found (%) C, 72.10; H, 5.15; N, 15.60.
Antibacterial: The biological activity of the newly synthe-
sized compounds 5a-j were assessed against Escherichia coli,
Staphylococcus aureus, Bacillus subtilis, Salmonella typhi
bacterial strains and Aspergillums niger and Candida albicans
fungal strains in term of disk diffusion method. As described
in previous work25.Amoxicillin and ketoconazole were utilized
as standard drugs for the bacteria and fungi, respectively.
Initially, a screening of phthalazine-derivatives and standard
drugs was accomplished at definite concentrations; 500 µg/mL.
The results was documented by calculating the inhibition zone
diameter at the end of 24 h for bacteria incubation and 72 h
for fungi as well. Each trial was repeated twice. Based on the
obtained results, the minimum inhibitory concentration (MIC)
of compounds; 5a-j against all bacterial and fungal strains
was further investigated by liquid dilution method as described
by El-Hashash et al.25, in which “stock solutions of the target
compounds of 500, 250, 200, 100, 62.5, 50, 25 and 12.5 µg
mL–1 concentrations were mixed with DMSO as solvent”.
Solutions of amoxicillin and ketoconazole, which considered
as standard drugs were arranged at the same concentrations.
Cultures of both bacteria and fungi were also prepared prior
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]-
azepin-1-yl) methyl)-4-(4-chlorophenyl)phthalazin-1(2H)-
ones(5c): m.p. 119-120 ºC; yield 56 %; 1H NMR (DMSO-d6)
δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax
,
cm-1): 1664 (CO); MS (70 eV) m/z (%):453 (M+, 11). Anal.
calcd. (%) for C26H20N5OCl: C, 68.80; H, 4.44; Cl, 7.81; N,
15.43; found (%) C, 68.82; H, 4.40; Cl, 7.85; N, 15.40.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]-azepin-
1-yl)methyl)-4-(3,4-dichlorophenyl)phthalazin-1(2H)-
ones(5d): m.p. 177-178 ºC; yield 60 %; 1H NMR (DMSO-d6) δ:
4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H); IR (KBr, νmax, cm-
1): 1666 (CO) ; MS (70 eV) m/z (%): 488 (M+, 14). Anal. calcd.
(%) for C26H19N5OCl2: C, 63.94; H, 3.92; Cl, 14.52; N, 14.34;
found (%) C, 63.90; H, 3.94; Cl, 14.52; N, 14.30.
2-((5,6-Dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-
1-yl)methyl)-4-(4-(4-chlorobenzyl)phenyl)-phthalazin-
1
1(2H)-ones (5e): m.p. 120-121 ºC; yield 54 %; H NMR
(DMSO-d6) δ: 4.91 (s, 2H, CH2), 7.01-8.23 (m, 14H, Ar-H);

Vol. 26, No. 22 (2014)
Synthesis and Antimicrobial Evaluation of Some New 4-Substituted Phthalazin-1(2H)-ones 7831
Ar
Compound
Ar
to the main test. Then, in a test tube series; 1 mL of phthalazine
compound solution; different concentrations together with
0.2 mL of bacteria/fungi was added. To the last solutions,
3.8 mL of sterile distilled water was added to each of the
previous test tubes. All tubes were left for incubation at 37 °C
for 24 h. The observed turbidity obtained is representing the
growth of both bacteria and fungi. This technique was repeated,
for comparison by altering the phthalazine compounds with
amoxicillin and ketoconazole. The minimum inhibitory concen-
tration, at which there is no growth, was detected as the MIC
value (Table-1). The comparison between the MICs (in µg/mL)
for the powerful compounds and standard drugs against all
tested microorganisms are represented in the Table-1.
Ar
2a
N
BrCH2COOEt
N
N
NH
COOEt
OCH3
Cl
b
c
d
e
f
O
O
2
1
Cl
Cl
H2
C
NH2NH2
Cl
Cl
CH
Ar
O
3
H3C
H3C
N
CH3
H2
g
h
i
N
CONHNH2
C
3
H2
C
N
j
RESULTS AND DISCUSSION
The target compound [4-substituted-1(2H)-oxo-phthalazin-
2yl] acetic acid hydrazide (3) in the present study was readily
obtained by the reaction of phthalazine acetic acid ethyl ester
2 with hydrazine hydrate, which in was turn prepared from
4-substituted-phthalazin-1(2H)-one (1).
for the methylene protons in the seven-membered ring: 2.05-
2.18 (2H, 5-H); 2.30-2.39 ppm (2H, 4-H) and two equal
intensity, broad signals at 2.66-2.76 and 2.95-3.11 ppm (each
1H, 6-H). The 13C NMR spectrum of compound 5a-j agrees
well with the proposed structure.
The structure of compounds 2a-j was confirmed on the
basis of their elemental analysis and spectral data. The IR
spectrum showed a characteristic absorption band at ν = 1742-
1733 cm-1 corresponding to CO of ester, CO of cyclic amide
at ν = 1665-1658 cm-1 and devoid any band for NH. The 1H
NMR spectrum of compound 2a-j showed a triplet signal at δ
1.33-1.48 assigned for CH3CH2, a quartet signal at 4.13-4.22
assigned for CH2CH3, a singlet at 4.70-4.82 assigned for
CH2CO. The hydrazide derivative 3a-j revealed absorption
bands at ν = 3188-3162 and 3458-3308 cm-1 corresponding to
NHNH2 groups. The 1HNMR spectrum of compound 5c showed
δ = 4.43 (s, 2H, NH2 exchangeable with D2O), 4.74 (s, 2H,
CH2CO), 9.3 (s, 1H, NH exchangeable with D2O) ppm and
aromatic protons.
Ar
Ar
O
N
N
OEt
O
N
N
base
N
N
O
N
N
NHNH2
4
3
5
Conclusion
We reported here the successful synthesis of different 2-
((5,6-dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepin-1-yl)
methyl)-4-substituted-phthalazin-1(2H)-ones. Most of the
newly synthesized compounds were tested for their antimicro-
bial and antiinflammatory activity. The antimicrobial activity
study revealed that all the compounds tested showed moderate
to good antibacterial and antifungal activities against pathogenic
strains. In case of antiinflammatory activity, compounds
showed good activity among the tested compounds.
Cyclocondensation of hydrazide derivatives 3a-j with
seven-membered lactim ether 4 afforded the corresponding
5,6-dihydro-4H-1,2,4-triazolo[4,3-a]benz[f]azepine deriva-
tives 5a-j. The structure of the tricycles 5 was confirmed on
the basis of their elemental analysis and spectral data. The IR
spectrum revealed no absorption for NHNH2 groups. The
features of the 1H NMR spectrum include very broad signals
TABLE-1
ANTIMICROBIAL ACTIVITY OF COMPOUNDS 5a-j
Minimum inhibitory concentration (MIC) in µg/mL
Bacterial strains
Compounds
Fungal strains
S. aureus
B. subtilis
S. typhi
E. coli
A. niger
C. albican
5a
5b
250
–
250
500
50
500
–
500
–
–
500
250
125
62.5
125
62.5
250
62.5
–
500
–
100
25
50
25
25
50
25
–
100
25
500
62.5
62.5
125
125
–
5c
5d
25
25
25
25
50
50
5e
50
50
5f
25
25
5g
250
50
–
25
500
25
5h
5i
25
–
125
500
–
500
6.25
–
500
6.25
–
200
6.25
–
5j
6.25
–
–
31.25
Amoxicillin
Ketaconazole
31.25

7832 El-Shamy et al.
ACKNOWLEDGEMENTS
Asian J. Chem.
E. Boss, R. Emmenegger, L. Ldsser, E. Masso, R. Roth, C. Schlachter,
W. Vetterli, D. Wyss and J.M. Wood, J. Med. Chem., 43, 2310 (2000).
10. J.M.Arif, M. Kunhi, A.A. Bekhit, M.P. Subramanian and K.Al-Hussein,
H.Y. Aboul-Enein Fahad and M. Al-Khodairy, Asian Pac. J. Cancer
Prev., 7, 249 (2006).
This work was supported by King Saud University,
Deanship of Scientific Research, College of Science, Research
Center. The author acknowledge the project "CEITEC -Central
European Institute of Technology (CZ.1.05/1.1.00/02.0068)
from European Regional Development Fund.
11. M. Yamaguchi, K. Kamei, T. Koga, M. Akima, T. Kuroki and N. Ohi,
J. Med. Chem., 36, 4052 (1993).
12. Y.X. Li, Y.P. Luo, Z. Xi, C.W. Niu, Y.Z. He and G.F. Yang, J. Agric.
Food Chem., 54, 9135 (2006).
13. F.H.H. Leenen, D.L. Smith, R.M. Farkas, R.A. Reeves andA. Marquez-
Julio, Am. J. Med., 82, 969 (1987).
REFERENCES
14. J.M. Leiro, E. Alvarez, J.A. Arranz, E. Cano and F. Orallo, Int.
Immunopharmacol., 4, 163 (2004).
1. (a) E.C. Franklin, Chem. Rev., 16, 305 (1935); (b) F.W. Bergstrom,
Chem. Rev., 35, 77 (1944); (c) F.W. Lichtenthaler, Acc. Chem. Res.,
35, 728 (2002); (d) V.P. Litvinov, Russ. Chem. Rev., 72, 69 (2003); (e)
Q.-X. Guo and Y. Xu, Heterocycles, 63, 903 (2004).
2. B. Abd El-Fattah, M.I. Al-Ashmawi, S. El-Feky and E. Roder, Egypt.
J. Pharm. Sci., 29, 259 (1988).
15. S. Tanaka, M. Tanaka and A. Akashi, Stroke, 20, 1724 (1989).
16. R. Moroi, K. Ono, T. Saito, T. Akimoto and M. Sano, Chem. Pharm.
Bull. (Tokyo), 25, 830 (1977).
17. J.P. Kemp, E.O. Meltzer, H.A. Orgel, M.J. Welch, G.A. Bucholtz, E.
Middleton Jr., S.L. Spector, J.J. Newton and J.L. Perhach Jr., J. Allergy
Clin. Immunol., 79, 893 (1987).
3. B.E. Bayoumy, S.A. El-Feky and M. El-Mobayed, Egypt. J. Chem.,
33, 267 (1991).
18. G. Scheffler, J. Engel, B. Kutscher, W.S. Sheldrick and P. Bell, Arch.
Pharmazie, 321, 205 (1988).
4. M.A. Khalil, S.M. El-Khawss and M.G. Kassem, Sci. Pharm., 48, 344
(1980).
19. P.F. Kador, J.H. Kinoshita and N.E. Sharpless, J. Med. Chem., 28, 841
(1985).
5. O.M. Boland, C.C. Blackwell, B.F. Clarke and D.J. Ewing, Diabetes,
42, 336 (1993).
20. B.L. Mylari, E.R. Larson, T.A. Beyer, W.J. Zembrowski, C.E. Aldinger,
M.F. Dee, T.W. Siegel and D.H. Singleton, J. Med. Chem., 34, 108 (1991).
21. S. Grasso, G. De Sarro, A. De Sarro, N. Micale, M. Zappalà, G. Puja,
M. Baraldi and C. De Micheli, J. Med. Chem., 43, 2851 (2000).
22. D. Viña, E. del Olmo, J.L. Lopez-Pérez and A. San Feliciano, Tetrahedron,
65, 1574 (2009).
6. Y. Hamamoto, K. Nagai, M. Muto and C. Asagami, Exp. Dermatol., 2,
231 (1993).
7. E. Olmo, B. Barboza, M.I. Ybarra, J.L. López-Pérez, R. Carrón, M.A.
Sevilla, C. Boselli and A.S. Feliciano, Bioorg. Med. Chem. Lett., 16,
2786 (2006).
8. M. Napoletano, G. Norcini, F. Pellacini, F. Marchini, G. Morazzoni, P.
Ferlenga and L. Pradella, Bioorg. Med. Chem. Lett., 10, 2235 (2000).
9. G. Bold, K.-H.Altmann, J. Frei, M. Lang, P.W. Manley, P.Traxler, B.Wietfeld,
J. Brüggen, E. Buchdunger, R. Cozens, S. Ferrari, P. Furet, F. Hofmann,
G. Martiny-Baron, J. Mestan, J. Rösel, M. Sills, D. Stover, F.Acemoglu,
23. F.F. Blicke and R.D. Swisher, J. Am. Chem. Soc., 56, 923 (1934).
24. E. Olmo, B. Barboza, M.I.Ybarra, J.L. López-Pérez, R. Carrón, M.A. Sevilla,
C. Boselli and A.S. Feliciano, Bioorg. Med. Chem. Lett., 16, 2786
(2006).