untitled


European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	

European	Journal	of	Chemistry	
ISSN	2153‐2249	(Print)	/	ISSN	2153‐2257	(Online)		2013	EURJCHEM	

DOI:10.5155/eurjchem.4.1.10‐19.707	

	
	

	

	

European	Journal	of	Chemistry	
Journal	homepage:	www.eurjchem.com	

	 	 	

Synthesis,	reactions	and	biological	evaluation	of	benzyltriazolophthalazine	
derivatives	

Ashraf	Hassan	Fekry	Abd	El‐Wahab	a,b,*,	Hany	Mostafa	Mohamed	a,c,	Ahmed	Mohamed	El‐Agrody	a,d,	
Mohamed	Ahmed	El‐Nassag	a	and	Ahmed	Hammam	Bedair	a	

a	Chemistry	Department,	Faculty	of	Science,	Al‐Azhar	University,	11884,	Nasr	City,	Cairo,	Egypt	
b	Chemistry	Department,	Faculty	of	Science,	Jazan	University,	2097,	Jazan,	Saudi	Arabia	
c	Chemistry	Department,	Faculty	of	Medicine,	Jazan	University,	82621,	Jazan,	Saudi	Arabia	
d	Chemistry	Department,	Faculty	of	Science,	King	Khalid	University,	9004,	Abha,	Saudi	Arabia	

*Corresponding	author	at:	Chemistry	Department,	Faculty	of	Science,	Al‐Azhar	University,	11884,	Nasr	City,	Cairo,	Egypt.		
Tel.:	+2.0100.8199893;	fax:	+2.02.22629358.	E‐mail	address:	ash_abdelwahab@yahoo.com	(A.H.F.A.	El‐Wahab).	

	
	

	 	

	 	 	
ARTICLE	INFORMATION	 	 ABSTRACT
Received:	09	November	2012	
Received	in	revised	form:	02	December	02012	
Accepted:	17	December	2012	
Online:	31	March	2013	

KEYWORDS	

	 A	 series	 of	 triazolophthalazine	 derivatives	 (4‐22)	were	 synthesized	 and	 characterized.	 The
structures	of	the	newly	synthesized	compounds	were	confirmed	by	spectral	data.	The	newly
synthesized	compounds	were	also	screened	for	their	antimicrobial	activity.	

Thioglycolic	acid	
Aromatic	aldehyde	
Knoevenagal	reaction		
Cyanoacetohydrazide		
Antimicrobial	activity	
4‐Benzyl‐1‐chlorophthalazine	

	
1.	Introduction	
	

Reports	of	the	synthesis	of	phthalazine‐1(H)‐one	derivative	
have	been	recently	published	[1‐9].	Phthalazine	derivatives	are	
important	 heterocyclic	 and	 are	 known	 to	 possess	 variety	 of	
biological	 activities	 such	 as	 antimicrobial,	 anticonvulsant,	
cardiotonic,	 vasorelaxant,	 antifungal,	 anticancer,	 antitumor	
agent,	 antianxiety	 drug,	 and	 anti‐inflammatory	 activities	 [10‐
19].	 Multiple	 reports	 indicates	 that	 arylaminophthalazine	
derivative	(Figure	1,	A)	act	as	inhibitor	of	vascular	endothelial	
growth	 factor	 (VEGFR‐2)	 has	 entered	 clinical	 testing	 against	
various	 cancers	 [20].	 Also,	 a	 series	 of	 1‐(isoquinoline‐5‐yl)‐4‐
arylaminophthalazine	 (Figure	 1,	 B)	 were	 studied	 as	 a	 potent	
inhibitors	of	VEGFR	and	the	later	compound	inhibit	VEGFR‐1,	a	
related	 receptor	 tyrosine	 kinase	 [21,22].	 γ‐Aminobutyric	 acid	
(GABA)	 is	 the	major	 inhibitory	 neurotransmitter	 in	 the	 brain	
[23].	 3‐Phenyl‐6‐(pyrid‐2‐ylmethloxy)‐[1,2,4]triazolo[3,4‐a]	
phthalazine	 (Figure	 1,	 C)	was	 identified	 as	 a	 class	 of	 GABA‐A	
receptor	ligands	with	large	improvement	in	binding	affinity	due	
to	 hydrogen‐bond‐donating	 interaction	 from	 the	 receptor	
adjacent	to	that	portion	of	the	molecule	[24]	(Figure	1,	C).	

In	 view	 of	 the	 above	 aforementioned	 facts,	 the	 author,	
undertook	 synthesis	 of	 some	 newly	 benzo‐fused	 ring	 of	 4‐
benzylphthalazine,	 such	 derivatives	 could	 possess	 interesting	
and	useful	biological	properties.	
	
2.	Experimental		
	
2.1.	Instrumentation	
	

Melting	points	were	determined	on	a	Stuart	melting	point	
apparatus	 and	 are	 uncorrected.	 IR	 spectra	 were	 recorded	 in	

KBr	 using	 a	 FT‐IR	 5300	 spectrometer	 and	 Perkin	 Elmer	
spectrum	RXIFT‐IR	system	(ν,	 cm−1).	The	 1H	NMR	at	300	MHz	
and	13C	NMR	spectra	at	75	MHz	were	recorded	in	DMSO‐d6	on	a	
Varian	Mercury	VX‐300	NMR	spectrometer.	Chemical	shifts	(δ)	
are	related	to	that	of	the	solvent.	Mass	spectra	were	measured	
on	a	Shimadzu	GC‐MS‐QP‐1000	EX	mass	spectrometer	at	70	eV.	
The	elemental	analyses	were	performed	at	the	Microanalytical	
Center,	Cairo	University,	Cairo,	Egypt.	

	

 

Figure	1.	Structures	of	arylaminophthalazine	(A	and	B)	and	
triazolophthalazine	derivatives	(C).	
	

2.2.	General	procedure	for	the	synthesis	of	4‐benzyl‐
phthalazine	derivatives	(2	and	3)	
	

A	mixture	 of	 4‐benzyl‐1‐chlorophthalazine	 (1)	 (0.25	 g,	 10	
mmol)	 and	 thiosemicarbazide	 or	 thiocarbohydrazide	 (10	
mmol)	 in	 absolute	 ethanol	 (30	mL)	was	 refluxed	 for	 3	 hours.	
The	solvent	was	evaporated	in	vacuum.	The	obtained	solid	was	
filtered	off	and	washed	with	ethanol	(Scheme	1).	



El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	 11	
 

	

 
	

Scheme	1
	
	
4‐Benzylphthalazin‐1‐yl‐thiol	 (2):	 Yellow	 crystals.	

Crystallization	from	ethanol.	Yield:	85%.	M.p.:	160‐162	°C.	FT‐
IR	 (KBr,	 v,	 cm−1):	 3150	 (NH),	 2908	 (SH).	 1H	 NMR	 (300	MHz,	
DMSO‐d6,	 δ,	 ppm):	 14.32	 (brs,	 1H,	 SH,	 exchangeable	 by	 D2O),	
8.75	 (d,	1H,	Ar‐H),	8.61	 (brs,	1H,	NH,	cancelled	by	D2O),	8.05‐
7.88	(m,	3H,	Ar‐H),	7.37‐7.18	(m,	5H,	Ar‐H),	4.40	(s,	2H,	CH2Ph).	
MS	 (m/z	 (%)):	 252	 (M+,	 83.8),	 251	 (100),	 220	 (3.3),	 219	
(14.34),	 218	 (39.8),	 191	 (3.2),	 165	 (7.4),	 89	 (11.1),	 76	 (9.4).	
Anal.	calcd.	for	C15H12N2S:	C,	71.40;	H,	4.79;	N,	11.10.	Found:	C,	
71.33;	H,	4.65;	N,	11.04%.	

4‐Benzylphthalazin‐1‐yl‐amine	 (3):	 Yellow	 crystals.	
Crystallization	from	ethanol.	Yield:	65%.	M.p.:	178‐179	°C.	FT‐
IR	(KBr,	v,	cm−1):	3274,	3204	(NH2),	1640	(C=N).	1H	NMR	(300	
MHz,	 DMSO‐d6,	 δ,	 ppm):	 8.65‐7.28	 (m,	 9H,	 Ar‐H),	 5.25	 (s,	 2H,	
CH2Ph),	 4.48	 (brs,	 2H,	 NH2,	 exchangeable	 by	 D2O).	 MS	 (m/z	
(%)):	235	(M+,	4.6),	107	(7.2),	106	(100),	105	(73.0),	76	(5.7).	
Anal.	 calcd.	 for	C15H13N3:	C,	76.57;	H,	5.57;	N,	17.86.	Found:	C,	
76.38;	H,	5.36;	N,	17.73%.	
	
2.3.	General	procedure	for	the	synthesis	of	triazolo‐
phthalazine	derivatives	(4	and	5)	
	 	

A	mixture	 of	 4‐benzyl‐1‐chlorophthalazine	 (1)	 (0.25	 g,	 10	
mmol)	 and	 (4‐benzyl‐1‐oxo‐1H‐phthalazin‐2yl)acetic	 acid	
hydrazide	 (0.30	 g,	 10	mmol)	 or	 cyanoacetohydrazide	 (0.09	 g,	
10	mmol)	in	absolute	ethanol	(30	mL)	and	2	drops	of	TEA	was	
refluxed	 for	 3	 hours.	 The	 solvent	was	 evaporated	 in	 vacuum.	
The	 obtained	 solid	 was	 filtered	 off	 and	 washed	 with	 ethanol	
(Scheme	1	and	2).	

4‐Benzyl‐2‐((6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)	
methyl)phthalazin‐1(2H)‐one	(4):	White	crystals.	Crystallization	
from	 dioxane.	 Yield:	 85%.	 M.p.:	 200‐202	 °C.	 FT‐IR	 (KBr,	 v,	
cm−1):	 3186	 (NH),	 3026	 (C‐H	 aromatic),	 1650	 (CO).	 1H	 NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	11.35,	11.14	(2s,	1H,	NH),	10.13,	
9.93	(2s,	1H,	NH),	7.90‐7.15	(m,	18H,	Ar‐H),	5.31,	4.96	(2s,	1H,	
=CHPh),	4.33	(d,	 J	=	4.5	Hz,	2H,	CH2),	4.16	(d,	 J	=	11.7	Hz,	2H,	
CH2).	13C	NMR	(75	MHz,	DMSO‐d6,	δ,	ppm):	167.77	(CO),	158.86,	
144.87,	144.74,	143.83,	138.19,	136.77,	133.26,	131.27,	131.05,	
128.79,	128.45,	128.39,	128.35,	128.29,	127.53,	127.46,	127.22,	
126.42,	 126.32,	 125.68,	 125.357,	 125.136,	 125.00,	 123.58,	
120.74,	120.69,	52.31	 (NCH2C),	37.66	 (CH2Ph),	37.56	 (CH2Ph).	
MS	 (m/z	 (%)):	 508	 (M+,	 95.6),	 417	 (100),	 (M‐CH2Ph),	 361	
(15.5),	 259	 (5.6),	 249	 (17.3),	 92	 (11.0),	 91	 (95.6).	Anal.	 calcd.	
for	 C32H24N6O:	 C,	 75.57;	H,	 4.76;	N,	 16.52.	 Found:	 C,	 75.34;	H,	
4.67;	N,	16.42%.	

6‐Benzyl([1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)acetonitrile	
(5):	 Yellow	 crystals.	 Crystallization	 from	 ethanol.	 Yield:	 85%.	
M.p.:	 160‐162	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 2900	 (CH	 aliphatic),	

2250	(CN).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	8.48,	8.22	(2d,	
J	=	8.1	Hz,	2H,	Ar‐H),	7.81	(d,	 J	=	7.2,	1H,	Ar‐H),	7.99‐7.19	(m,	
4H,	 Ar‐H),	 7.62,	 7.28	 (2d,	 J	 =	 7.2	 Hz,	 2H,	 Ar‐H),	 4.72	 (s,	 2H,	
CH2Ph),	4.57	(s,	2H,	CH2CN).	MS	(m/z	(%)):	299	(M+,	59.5),	298	
(100),	271	(16.8),	205	(7.0),	128	(15.2),	102	(18.1),	91	(74.7),	
66	(5.1),	53	(3.5).	Anal.	calcd.	for	C18H13N5:	C,	72.23;	H,	4.38;	N,	
23.40.	Found:	C,	72.07;	H,	4.20;	N,	23.29%.	
	
2.4.	General	procedure	for	the	synthesis	of	triazolo‐
phthalazineacrylonitrile	derivatives	(6a‐d)	
	

A	 mixture	 of	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)aceto‐nitrile	 (5)	 (0.29	g,	10	mmol)	 and	aromatic	 aldehydes	
(10	 mmol)	 in	 absolute	 ethanol	 (30	 mL)	 and	 2	 drops	 of	
piperidine	 was	 refluxed	 for	 2	 hours.	 The	 solvent	 was	
evaporated	in	vacuum.	The	obtained	solid	was	filtered	off	and	
washed	with	ethanol	(Scheme	2).	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐phenyl‐
acrylonitrile	(6a):	Yellow	crystals.	Crystallization	from	dioxane.	
Yield:	 80%.	M.p.:	 230‐232	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 3038	 (CH‐
aromatic),	2917	(CH	aliphatic),	2223	(CN).	1H	NMR	(300	MHz,	
DMSO‐d6,	δ,	ppm):	8.48,	8.22	(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	7.81	(d,	J	
=	7.2,	1H,	Ar‐H),	8.00‐7.22	(m,	9H,	Ar‐H),	7.64,	7.30	(2d,	J	=	7.2	
Hz,	2H,	Ar‐H),	7.05	(s,	1H,	=CH),	4.75	(s,	2H,	CH2Ph).	MS	(m/z	
(%)):	 387	 (M+,	 5.3),	 386	 (12.3),	 91	 (100).	 Anal.	 calcd.	 for	
C25H17N5:	C,	77.50;	H,	4.42;	N,	18.08.	Found:	C,	77.41;	H,	4.35;	N,	
17.97%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐p‐tolyl‐
acrylonitrile	(6b):	Yellow	crystals.	Crystallization	from	dioxane.	
Yield:	 90%.	M.p.:	 258‐260	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 2910	 (CH	
aliphatic),	 2216	 (CN).	 1H	 NMR	 (300	 MHz,	 DMSO‐d6,	 δ,	 ppm):	
8.49,	8.27	(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	7.85	(d,	J	=	7.2,	1H,	Ar‐H),	
8.02‐7.21	 (m,	 8H,	 Ar‐H),	 7.63,	 7.29	 (2d,	 J	 =	 7.2	Hz,	 2H,	 Ar‐H),	
7.08	(s,	1H,	=CH),	4.74	(s,	2H,	CH2Ph),	2.36	(s,	3H,	CH3).	MS	(m/z	
(%)):	 401	 (M+,	 40.6),	 400	 (100),	 91	 (70.7).	 Anal.	 calcd.	 for	
C26H19N5:	C,	77.79;	H,	4.77;	N,	17.44.	Found:	C,	77.65;	H,	4.64;	N,	
17.37%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐(4‐meth‐
oxyphenyl)acrylonitrile	 (6c):	 Yellow	 crystals.	 Crystallization	
from	 dioxane.	 Yield:	 87%.	 M.p.:	 264‐266	 °C.	 FT‐IR	 (KBr,	 v,	
cm−1):	 2924	 (CH	 aliphatic),	 2216	 (CN).	 1H	 NMR	 (300	 MHz,	
DMSO‐d6,	δ,	ppm):	8.45,	8.19	(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	7.88	(d,	J	
=	7.2,	1H,	Ar‐H),	8.11‐7.24	(m,	8H,	Ar‐H),	7.61,	7.27	(2d,	J	=	7.2	
Hz,	2H,	Ar‐H),	7.14	(s,	1H,	=CH),	4.72	(s,	2H,	CH2Ph),	3.82	(s,	3H,	
OCH3).	MS	(m/z	(%)):	417	(M+,	6.6),	416	(49.5),	91	(100).	Anal.	
calcd.	for	C26H19N5O:	C,	74.80;	H,	4.59;	N,	16.78.	Found:	C,	74.63;	
H,	4.7;	N,	16.66%.		

	



12	 El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	
	

	 	

 
	

Scheme	2
	
	
2‐(6‐Benzyl[1,2,4]tri‐azolo[3,4‐a]phthalazin‐3‐yl)‐3‐(4‐hyd‐

roxyphenyl)acrylonitrile	 (6d):	 Yellow	 crystals.	 Crystallization	
from	 dioxane.	 Yield:	 85%.	 M.p.:	 298‐300	 °C.	 FT‐IR	 (KBr,	 v,	
cm−1):	3432	(OH),	2920	(CH	aliphatic),	2220	(CN).	1H	NMR	(300	
MHz,	DMSO‐d6,	δ,	ppm):	9.	80	(s,	1H,	OH),	8.65,	8.41	(2d,	J	=	8.1	
Hz,	2H,	Ar‐H),	8.25	(s.	1H,	=CH),	7.79	(d,	J	=	7.2,	1H,	Ar‐H),	8.00‐
7.54	(m,	8H,	Ar‐H),	7.61,	7.32	(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	4.69	(s,	
2H,	CH2Ph).	MS	(m/z	(%)):	403	(M+,	13.8),	402	(48),	401	(51.4),	
91	(100),	90	(81).	Anal.	calcd.	for	C25H17N5O:	C,	74.43;	H,	4.25;	
N,	17.36.	Found:	C,	74.22;	H,	4.09;	N,	17.25%.	
	
2.5.	General	procedure	for	the	synthesis	of	triazolo‐
phthalazinechromene	derivatives	(7‐10)	
	

A	 mixture	 of	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)acetonitrile	 (5)	 (0.29	 g,	 10	mmol)	 and	 phenolic	 aldehydes	
(salicylaldehyde,	 2‐hydroxy‐1‐naphthaldehyde	 and	 2,7‐
dihydroxy‐1‐naphthaldehyde)	 (10	 mmol)	 in	 absolute	 ethanol	
(30	mL)	and	2	drops	of	piperidine	was	refluxed	for	2	hours.	The	
obtained	 solid	 was	 filtered	 off	 and	 washed	 with	 ethanol	
(Scheme	3).	

3‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐2H‐
chromen‐2‐imine	 (7):	 Yellow	 crystals.	 Crystallization	 from	
ethanol.	 Yield:	 95%.	 M.p.:	 266‐268	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	
3228	 (NH),	 3056	 (CH	 aromatic),	 1642	 (C=N),	 2924	 (CH	
aliphatic).	 1H	NMR	(300	MHz,	DMSO‐d6,	 δ,	ppm):	10.20	 (s,	1H,	
NH,	exchangeable	by	D2O),	9.20	(s,	1H,	4H,	chromene),	8.48	(s,	
1H,	Ar‐H),	8.63‐7.23	(m,	12H,	Ar‐H),	4.71	(s,	2H,	CH2Ph).	Anal.	
calcd.	for	C25H17N5O:	C,	74.43;	H,	4.25;	N,	17.36.	Found:	C,	74.16;	
H,	4.07;	N,	17.23%.	

3‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐chromen‐2‐
one	(8):	Yellow	crystals.	Crystallization	from	DMF.	Yield:	90%.	
M.p.:	>	340	°C.	FT‐IR	(KBr,	v,	cm−1):	3046	(CH	aromatic),	2925	
(CH	 aliphatic),	 1732	 (CO).	 1H	 NMR	 (300	 MHz,	 DMSO‐d6,	 δ,	
ppm):	9.20	(s,	1H,	4H,	chromene),	8.48	(s,	1H,	Ar‐H),	8.63‐7.23	
(m,	 12H,	 Ar‐H),	 4.71	 (s,	 2H,	 CH2Ph).	 MS	 (m/z	 (%)):	 404	 (M+,	
100),	 403	 (99.9),	 204	 (11.3),	 91	 (60.4).	 Anal.	 calcd.	 for	
C25H16N4O4:	C,	74.25;	H,	3.99;	N,	13.85.	Found:	C,	74.02;	H,	3.84;	
N,	13.76%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3H‐benzo	
[f]chromen‐3‐imine	 (9a):	 Yellow	 crystals.	 Crystallization	 from	
ethanol.	 Yield:	 92%.	 M.p.:	 276‐278	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	
3248	(NH),	2928	(CH	aliphatic),	1638	(C=N).1H	NMR	(300	MHz,	
DMSO‐d6,	δ,	ppm):	10.03	(s,	1H,	NH;	exchangeable	by	D2O),	9.46	
(s,	1H,	benzochromene‐4‐H),	8.6	(d,	J	=	8	Hz,	1H,	Ar‐H),	8.38	(d,	
J	=	7.4	Hz,	1H,	Ar‐H),	8.16	(d,	J	=	9.3	Hz,	1H,	Ar‐H),	7.93	(d,	J	=	
7.2	Hz,	1H,	Ar‐H)	8.07‐7.15	(m,	11H,	Ar‐H),	4.73	(s,	2H,	CH2Ph).	
Anal.	calcd.	for	C29H19N5O:	C,	76.81.;	H,	4.22;	N,	15.44.	Found:	C,	
76.55;	H,	4.13;	N,	15.30%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐imino‐
3H‐benzo[f]chromen‐9‐ol	 (9b):	 White	 crystals.	 Crystallization	
from	DMF.	Yield:	85%.	M.p.:	>	340	°C.	FT‐IR	(KBr,	v,	cm−1):	3280	
(NH),	3476	(OH),	1638	(C=N).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	
ppm):	10.09	(brs,	1H,	NH,	exchangeable	by	D2O),	9.42	(brs,	1H,	
OH,	 exchangeable	by	D2O),	9.28	 (s,	 1H,	 benzochromene	 ‐	4H),	
8.61,	8.34	(2d,	 J	=	7.8	Hz,	2H,	Ar‐H),	8.29‐7.10	(m,	12H,	Ar‐H),	
4.75	 (s,	 2H,	 CH2Ph).	 Anal.	 calcd.	 for	 C29H19N5O2:	 C,	 74.19;	 H,	
4.08;	N,	14.92.	Found:	C,	74.03;	H,	3.95;	N,	14.85%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐benzo[f]	
chromen‐3‐one	 (10a):	 Yellow	 crystals.	 Crystallization	 from	
dioxane.	 Yield:	 90%.	 M.p.:	 298‐300	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	
3043,	 (CH	aromatic),	1726	(CO).	 1H	NMR	(300	MHz,	DMSO‐d6,	
δ,	ppm):	9.48	(s,	1H,	benzochromene‐4‐H),	8.62	(d,	J	=	8	Hz,	1H,	
Ar‐H),	8.37	(d,	J	=	7.4	Hz,	1H,	Ar‐H),	8.18	(d,	J	=	9.3	Hz,	1H,	Ar‐
H),	7.90	(d,	J	=	7.2	Hz,	1H,	Ar‐H)	8.08‐7.16	(m,	11H,	Ar‐H),	4.74	
(s,	 2H,	 CH2Ph).	MS	 (m/z	 (%)):	 454	 (M+,	 100),	426	 (25.9),	 410	
(3.9),	 382	 (3.3),	 35	 (3.3),	 268	 (3.5),	 232	 (3.6),	 205	 (2.2),	 189	
(5),	164	(5.1),	91	(27.2).	Anal.	calcd.	for	C29H18N4O2:	C,	76.64;	H,	
3.99;	N,	12.33.	Found:	C,	76.50;	H,	3.87;	N,	12.18	%.	

2‐(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐9‐hydroxy	
benzo[f]chromen‐3‐one	 (10b):	 White	 crystals.	 Crystallization	
from	DMF.	Yield:	85%.	M.p.:	>	340	°C.	FT‐IR	(KBr,	v,	cm−1):	3452	
(OH),	 2928	 (CH	 aliphatic),	 1720	 (CO).	 1H	 NMR	 (300	 MHz,	
DMSO‐d6,	 δ,	 ppm):	 9.50	 (brs,	 1H,	 OH,	 exchangeable	 by	 D2O),	
9.30	(s,	1H,	benzochromene	‐	4H),	8.60,	8.35	(2d,	J	=	7.8	Hz,	2H,	
Ar‐H),	8.29‐7.12	 (m,	12H,	Ar‐H),	4.76	 (s,	2H,	CH2Ph).	MS	 (m/z	
(%)):	 470	 (M+,	 3.09),	 445	 (35.26),	 400	 (13.61),	 385	 (19.59),	
368	 (15.05),	 341	 (27.01),	 311	 (11.55),	 296	 (34.43),	 284	
(29.07),	 224	 (8.87),	 193	 (49.9),	 149	 (39.59),	 104	 (100),	 76	
(30.93).	Anal.	calcd.	for	C29H18N4O3:	C,	74.03;	H,	3.86;	N,	11.91.	
Found:	C,	73.90;	H,	3.73;	N,	11.76%.	
	
2.6.	General	procedure	for	the	synthesis	of	phthalazine‐
hydrazo	acetonitrile	derivatives	(11	and	12)	
	

To	 a	 stirred	 solution	 of	 (6‐benzyl[1,2,4]triazolo[3,4‐
a]phthalazin‐3‐yl)acetonitrile	(5)	(0.29	g,	10	mmol)	 in	ethanol	
(50	mL)	containing,	sodium	acetate	(3	g)	p‐tolyldiazonium	salt	
or	 triazolediazonium	 salt	 (prepared	 by	 adding	 sodium	 nitrite	
(10	mmol)	 to	p‐toluidine	 (0.12	g,	10	mmol)	or	1,2,4‐triazol‐3‐
amine	(0.13	g,	10	mmol)	 in	conc.	HCl	 (6	mL)	at	0~5	oC	under	
stirring	was	added	dropwise	The	reaction	mixture	was	then	left	
at	room	temperature	for	2	hours.	and	the	solid	product	formed	
was	collected	by	filtration	(Scheme	4).	

6‐Benzyl‐N'‐(p‐tolyl)‐[1,2,4]triazolo[3,4‐a]phthalazine‐3‐
carbohydrazonoyl	cyanide	(11):	Yellow	crystals.	Crystallization	
from	ethanol.	Yield:	80%.	M.p.:	172‐174	°C.	FT‐IR	(KBr,	v,	cm−1):	
3082	(NH),	2220	(CN),	1590	(C=N).		



El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	 13	
 

	

N

N

CH2Ph

N N

O

NH

N

N

CH2Ph

N N

O

O

N

N

CH2Ph

N N

O

NH

R
N

N

CH2Ph

N N

CN

CHO

OH

CHO

OHR

EtOH, Pip. / Heat

EtOH, Pip / Heat

AcOH / AcONa

AcOH / AcONa

7 8

9a; R= H 10a; R= H
b; R= OH b; R= OH

5

N

N

CH2Ph

N N

O

O

R

 
	

Scheme	3
	
	

 

Scheme	4	
	
	

1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	14.01,	13.60	(2s,	2H,	NH,	
exchangeable	by	D2O),	8.63,	8.26(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	8.51,	
8.33	(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	8.04‐	7.18	(m,	9H,	Ar‐H),	4.72	(s,	
2H,	CH2Ph),	1.32	(s,	3H,	CH3).	MS	(m/z	(%)):	417	(M+,	13.1),	416	
(13.3),	388	 (5.3),	203	 (2.1),	128	 (2.3),	103	 (2.1),	 91	 (100),	90	
(96.0),	77	(8.3),	76	(7.6),	65	(29.1).	Anal.	calcd.	for	C25H19N7:	C,	
71.93;	H,	4.59;	N,	23.49.	Found:	C,	71.35;	H,	4.38;	N,	23.33%.	

(6‐Benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐[(4H‐[1,2,4]	
triazolo‐3‐yl)hydrazono]acetonitrile	 (12):	 Orange	 crystals.	
Crystallization	from	ethanol.	Yield:	80%.	M.p.:	180‐182	°C.	FT‐
IR	(KBr,	v,	 cm−1):	3076	(NH),	2224	(CN),	1658	(C=N).	1H	NMR	
(300	 MHz,	 DMSO‐d6,	 δ,	 ppm):	 14.00,	 13.60	 (2s,	 2H,	 NH,	
exchangeable	by	D2O),	12.60	(s,	1H,	triazolo‐H),	8.64,	8.25	(2d,	J	
=	7.2	Hz,	2H,	Ar‐H),	8.52,	8.35	(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	8.04‐
7.18	 (m,	 5H,	 Ar‐H),	 4.72	 (s,	 2H,	 CH2Ph).	 MS	 (m/z	 (%)):	 394	
(61.9),	 393	 (51.2),	 286	 (7.7),	 231	 (6.6),	 129	 (7.7),	 128	 (4.8),	
103	(7.1),	91	(100).	Anal.	calcd.	for	C20H14N10:	C,	60.91;	H,	3.58;	
N,	35.51.	Found:	C,	60.78;	H,	3.45;	N,	35.42%.	
	
2.7.	Synthesis	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐
3‐yl)‐3‐ethoxyacrylonitrile	(13)	
	

A	 mixture	 of	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)acetonitrile	 (5)	 (10	 mmol)	 and	 triethyl	 orthoformate	 in	
acetic	anhydride	(15	mL)	was	refluxed	for	5	hours.	The	solvent	

was	evaporated	in	vacuum.	The	solid	product	was	collected	by	
filtration	 and	 washed	 with	 ethanol.	 Yellow	 crystals.	
Crystallization	from	benzene	(Scheme	5).	Yield:	95%.	M.p.:	170‐
171	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 3070	 (CH‐aromatic),	 2936	 (CH‐
aliphatic),	 2256	 (CN).	 1H	 NMR	 (300	 MHz,	 DMSO‐d6,	 δ,	 ppm):	
8.25	(s,	1H,	=CH),	8.53‐7.19	(m,	9H,	Ar‐H),	4.72	(s,	2H,	CH2Ph),	
4.28	 (q,	 2H,	 CH2CH3),	 1.30	 (t,	 3H,	 CH2CH3).	 Anal.	 calcd.	 for	
C21H17N5O:	C,	70.97;	H,	4.82;	N,	19.71.	Found:	C,	70.82;	H,	4.76;	
N,	19.58%.	
	
2.8.	General	procedure	for	the	synthesis	of	triazolo‐
phthalzine	derivatives	(14	and	15)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)‐3‐ethoxyacrylonitrile	(13)	(10	mmol)	and	NH2OH.HCl	(15	m	
mol)	or	NH2CSNH2	(10	mmol)	in	ethanol	(30	mL)	fused	sodium	
acetate	 (25	 mmol)	 was	 added.	 The	 resulting	 mixture	 was	
refluxed	 for	 3	 hrs	 and	 then	 allowed	 at	 cool	 to	 room	
temperature	 and	 diluted	 with	 water	 (20	 mL).	 The	 obtained	
solid	was	filtered	off	and	washed	with	ethanol	(Scheme	5).	

3‐Amino‐2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐
(hydroxyimino)prop‐1‐enyl	 acetate	 (14):	 White	 crystals.	
Crystallization	from	ethanol.	Yield:	80	%.	M.p.:	220‐222	°C.	FT‐
IR	 (KBr,	 v,	 cm−1):	 3382	 (OH),	 3284,	 3192	 (NH2),	 1644	 (CO),	
1612	(C=N).	



14	 El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	
	

	 	

 
	

Scheme	5	
	

	

1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	10.15	(s,	1H,	OH),	8.80	(s,	
1H,=CH),	8.48,	8.22	 (2d,	 J	 =	8.1	Hz,	2H,	Ar‐H),	7.81	 (d,	 J	 =	7.2,	
1H,	Ar‐H),	8.14‐7.23	(m,	4H,	Ar‐H),	7.62,	7.28	(2d,	J	=	7.2	Hz,	2H,	
Ar‐H),	 6.50	 (br,	 2H,	 NH2),	 4.74	 (s,	 2H,	 CH2Ph),	 3.37	 (s,	 3H,	
COCH3).	MS	 (m/z	 (%)):	402	 (M+,	100),	370	 (80.9),	345	 (57.4),	
344	(53.2),	328	(40.4),	274	(85.1),	236	(59.6),	192	(21.3),	118	
(21.8),	55	(36.2).	Anal.	calcd.	for	C21H18N6O3:	C,	62.68;	H,	4.51;	
N,	20.88.	Found:	C,	62.56;	H,	4.39;	N,	20.74%.	

4‐Amino‐5‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐
1H‐pyrimidine‐2‐thione	 (15):	 Yellow	 crystals.	 Crystallization	
from	 dioxane.	 Yield:	 85%.	 M.p.:	 275‐	 277	 °C.	 FT‐IR	 (KBr,	 v,	
cm−1):	3244	(NH2),	3056	(NH),	1640	(C=S).	1H	NMR	(300	MHz,	
DMSO‐d6,	 δ,	 ppm):	 9.32	 (s,1H,	NH),	 8.67	 (s,	 1H,CH),	8.50,	8.24	
(2d,	J	=	8.1	Hz,	2H,	Ar‐H),	7.81	(d,	 J	=	7.2,	1H,	Ar‐H),	7.99‐7.19	
(m,	4H,	Ar‐H),	7.62,	7.28	(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	6.40	(br,	2H,	
NH2),	 4.72	 (s,	 2H,	 CH2Ph).	MS	 (m/z	 (%)):	 385	 (M+,	 19.4),	 327	
(100),	 326	 (14.7),	 163	 (15.3),	 91	 (17.9).	 Anal.	 calcd.	 for	
C20H15N7S:	C,	62.32;	H,	3.92;	N,	25.44.	Found:	C,	62.11;	H,	3.76;	
N,	25.35%.	
	
2.9.	Synthesis	of	6‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐
3‐yl)‐8H‐[1,2,4]triazolo[4,3‐a]pyrimidin‐5‐ylideneamine	
(16)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)‐3‐ethoxyacrylonitrile	 (2)	 (10	 mmol)	 and	 3‐amino‐1,2,4‐
triazolo	(10	mmol)	in	DMF	(30	mL)	was	refluxed	for	3	hrs.	The	
solvent	 was	 evaporated	 in	 vacuum.	 The	 solid	 product	 was	
collected	by	filtration	and	washed	with	ethanol.	Brown	crystals.	
Crystallization	from	dioxane	(Scheme	5).	Yield:	85%.	M.p.:	280‐	
282	°C.	FT‐IR	(KBr,	v,	cm−1):	3184	(NH),	1632,	1602	(C=N).	1H	
NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	11.34	(s,	1H,	CH=N‐triazol),	
10.02	(s,1H,	NH),	8.88	(s,	1H,	CH‐pyrimidine),	8.48,	8.22	(2d,	J	=	
8.1	Hz,	2H,	Ar‐H),	7.81	(d,	 J	=	7.2,	1H,	Ar‐H),	7.99‐7.19	(m,	4H,	
Ar‐H),	7.63,	7.29	(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	5.70	(s,	1H,	NH),	4.72	
(s,	 2H,	 CH2Ph).	MS	 (m/z	 (%)):	 393	 (M+,	 51.4),	 90	 (100).	 Anal.	

calcd.	for	C21H15N9:	C,	64.11;	H,	3.84;	N,	32.04.	Found:	C,	64.03;	
H,	3.76;	N,	31.87%.	

	
2.10.	General	procedure	for	the	synthesis	of	hydrazonate	
and	acrylonitrile	derivatives	(17	and	18)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)‐3‐ethoxyacrylonitrile	 (13)	 (10	 mmol)	 and	 hydrazine	
hydrate	 (20	mmol)	 or	 phenylhydrazine	 (10	mmol)	 in	 ethanol	
(30	mL).	Solvent	was	 removed	by	 rotary	 evaporation	 and	 the	
obtained	 solid	 was	 filtered	 off	 and	 washed	 with	 dil.	 ethanol	
(Scheme	6).		

Ethyl	 3‐amino‐2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)‐3‐hydrazonopropane	 hydrazonate	 (17):	 While	 crystals.	
Crystallization	from	benzene.	Yield:	75%.	M.p.:	270‐	272	°C.	FT‐
IR	 (KBr,	v,	 cm−1):	3198	 (NH),	1598	 (C=N).	 1H	NMR	 (300	MHz,	
DMSO‐d6,	δ,	ppm):	8.48	(s,	1H,CH),	8.50,	8.24	(2d,	J	=	8.1	Hz,	2H,	
Ar‐H),	 7.81	 (d,	 J	 =	 7.2,	 1H,	 Ar‐H),	 8.27‐7.25	 (m,	 8H,	 Ar‐H	 and	
2NH2),	7.62,	7.28	(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	6.48	(br,	2H,	NH2),	
4.72	(s,	2H,	CH2Ph),	3.34	(q,	J	=	7.1	Hz,	2H,	CH2),	15.1	(t,	J	=	7.1	
Hz,	 3H,CH3).	 MS	 (m/z	 (%)):	 417	 (M+,	 32.6),	 371	 (M+‐C2H5OH,	
17.4),	 339	 (M+‐	 C2H5OH,	 N2H4,	 63.6),	 298	 (M+‐	 C2H5OH,	 N2H4,	
N2CH,	22.5),	272	(15.3),	234	(7.6),	128	(4.2),	91	(PhCH2+,	100).	
Anal.	calcd.	for	C21H23N9O:	C,	60.42;	H,	5.55;	N,	30.20.	Found:	C,	
60.20;	H,	5.35;	N,	30.05%.	

2‐(6‐Benzyl‐[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐ethoxy‐
3‐(2‐phenylhydrazinyl)acrylonitrile	 (18):	 While	 crystals.	
Crystallization	from	dioxane.	Yield:	70%.	M.p.:	278‐	280	°C.	FT‐
IR	 (KBr,	 v,	 cm−1):	 3212	 (NH),	 2198	 (CN),	 1526	 (C=C),	 1643	
(C=N).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	8.56,	8.32	(2d,	J	=	
8.1	Hz,	2H,	Ar‐H),	7.76	(d,	J	=	7.2,	1H,	Ar‐H),	8.30‐7.41	(m,	10H,	
Ar‐H	and	NH),	7.57,	7.21	(2d,	J	=	7.2	Hz,	2H,	Ar‐H),	6.78	(br,	1H,	
NH),	4.62	(s,	2H,	CH2Ph),	3.31	(q,	J	=	7.1	Hz,	2H,	CH2),	1.40	(t,	J	=	
7.1	Hz,	3H,	CH3).	MS	 (m/z	 (%)):	461	 (M+,	100),	371	 (M+‐C7H6,	
96.9),	 298	 (M+‐C7H6,	 ‐CH3OC=N.NH2,	 40.9),	 206	 (13.4),	 120	
(18.1).	 Anal.	 calcd.	 for	 C27H23N7O:	 C,	 70.27;	 H,	 5.02;	 N,	 21.24.	
Found:	C,	70.04;	H,	4.89;	N,	21.13%.	



El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	 15	
 

	

2

	
Scheme	6	

	
	

E
tO
H
/p
ip

 
	

Scheme	7
	
	
2.11.	Synthesis	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]	
phthalazin‐3‐ylmethyl)thiazol‐4‐one	(19)	
	

A	 mixture	 of	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)acetonitrile	(13)	(10	mmol)	and	thioglycolic	acid	(10	mmol)	
in	pyridine	(10	mL)	was	refluxed	for	3	hours.	The	solvent	was	
removed	on	rotary	evaporation	the	solid	obtained	was	filtered	
off,	 washed	 with	 ethanol.	 Gray	 crystals.	 Crystallization	 from	
dioxane	(Scheme	7).	Yield:	85%.	M.p.:	260‐262	°C.	FT‐IR	(KBr,	
v,	 cm−1):	 2924	 (CH‐aliphatic),	 1726	 (CO).	 1H	 NMR	 (300	MHz,	
DMSO‐d6,	δ,	ppm):	11.43	(s,	1H,	OH,	exchangeable	by	D2O),	8.44,	
7.92	(2d,	2H,	Ar‐H),	8.15	(d,	1H,	Ar‐H),	7.84‐7.18	(m,	6H,	Ar‐H),	
6.45	(s,	1H,	CH‐thiazolidinone),	4.55	(s,	2H,	CH2Ph),	4.08	(s,	2H,	
CH2),	3.92	(s,	2H,	CH2).	MS	(m/z	(%)):	373	(M+,	13.1),	374	(M+1,	
4.1),	375	(M+2,	2.6),	372	(1.9),	340	(2.4),	300	(2.1),	299	(3.4),	
271	(0.6),	128	(2.1),	102	(4.5),	91	(100),	66	(7.5),	53	(2.8).	Anal.	
calcd.	 for	 C20H15N5OS:	 C,	 64.33;	 H,	 4.05;	 N,	 18.75.	 Found:	 C,	
64.20;	H,	3.96;	N,	18.62%.	
	

2.12.	Synthesis	of	2‐((6‐benzyl‐[1,2,4]triazolo[3,4‐a]	
phthalazin‐3‐yl)methyl)‐5‐(4‐methoxybenzylidene)thiazol‐
4‐one	(20)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
ylmeth‐yl)thiazolidin‐4‐one	 (19)	 (10	 mmol)	 and	 p‐anis‐
aldehyde	 (10	 mmol)	 in	 ethanol	 (20	 mL)	 and	 few	 drops	 of	
piperidine	was	 refluxed	 for	 3	hours.	 The	mixture	 then	 cooled	
and	 the	 separated	 solid	was	 filtered	 off	washed	with	 ethanol.	
Yellow	crystals.	Crystallization	from	dioxane	(Scheme	7).	Yield:	
90%.	 M.p.:	 280‐282	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 3058	 (CH‐
aromatic),	2936	(CH‐aliphatic),	1682	(CO),	1626	(C=N).	1H	NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	9.	01	(s,	1H,	=CH),	8.48,	8.22	(2d,	
J=	8.1	Hz,	2H,	Ar‐H),	7.81	(d,	J	=	7.2,	1H,	Ar‐H),	7.99‐7.94,	7.86‐
7.83,	7.27‐7.19	(m,	8H,	Ar‐H),	7.62,	7.28	(2d,	J	=	7.2	Hz,	2H,	Ar‐
H),	4.72	(s,	2H,	CH2Ph),	3.74	(s,	3H,	OCH3),	3.90	(s,	2H,	CH2).	MS	
(m/z	 (%)):	 491	 (M+,	 95.1),	 459	 (2.0),	 300	 (23.2),	 299	 (95.1),	
193	 (32.0),	 165	 (20.1),	 164	 (20),	 149	 (20.7),	 91	 (100).	 Anal.	
calcd.	 for	 C28H21N5O2S:	 C,	 68.41;	 H,	 4.31;	 N,	 14.25.	 Found:	 C,	
68.30;	H,	4.22;	N,	14.18%.	



16	 El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	
	
	

 
	

Scheme	8
	
	
2.13.	Synthesis	of	2‐((6‐benzyl‐[1,2,4]triazolo[3,4‐a]	
phthalazin‐3‐yl)methyl)‐7‐(4‐methoxyphenyl)‐5‐oxo‐6,7‐
dihydro‐5H‐pyrano[2,3‐d]thiazole‐6‐carbonitrile	(21)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
ylmeth‐yl)thiazolidin‐4‐one	 (19)	 (10	 mmol)	 and	 p‐
anisaldehyde	 (10	 mmol)	 and	 malononitrile	 (10	 mmol)	 in	
absolute	 ethanol	 (30	 mL)	 and	 few	 drops	 of	 piperidine	 was	
refluxed	 for	 3	 hours.	 The	 mixture	 then	 cooled	 and	 the	
separated	 solid	was	 filtered	off	washed	with	ethanol	 (Scheme	
8).	 Yellow	 crystals.	 Crystallization	 from	 dioxane.	 Yield:	 80%.	
M.p.:	 302‐304	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 2924	 (CH‐aliphatic),	
2190	 (CN),	 1690	 (CO).	 1H	NMR	 (300	MHz,	DMSO‐d6,	 δ,	 ppm):	
8.42	(d,	1H,	Ar‐H),	8.25	(d,	1H,	Ar‐H),	7.97‐7.66	(m,	11H,	Ar‐H),	
5.38	(s,	2H,	CH2Ph),	4.72,	4.63	(2d,	2H,	H‐3	&	H‐4‐pyran),	3.78	
(s,	2H,	‐CH2‐),	3.58	(s,	3H,	OCH3).	Anal.	calcd.	for	C31H22N6O3S:	C,	
66.65;	H,	3.97;	N,	15.04.	Found:	C,	66.48;	H,	3.81;	N,	14.88%.	
	
	
	
	

2.14.	Synthesis	of	5‐amino‐8‐(6‐benzyl‐[1,2,4]triazolo[3,4‐
a]phthalazin‐3‐yl)‐2‐(4‐methylbenzylidene)‐3‐oxo‐7‐							
(p‐tolyl)‐3,7‐dihydro‐2H‐thiazolo[3,2‐a]pyridine‐6‐
carbonitrile	(22)	
	

A	mixture	of	2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl‐methyl)thiazolidin‐4‐one	 (19)	 (10	 mmol)	 and	 p‐
tolualdehyde	 (20	 mmol)	 and	 malononitrile	 (10	 mmol)	 in	
absolute	ethanol	/	dioxane	(30	mL)	and	few	drops	of	piperidine	
was	 refluxed	 for	 4	 hours.	 The	 mixture	 then	 cooled	 and	 the	
separated	solid	was	 filtered	off	washed	with	ethanol	 (Scheme	
8).	Yellow	crystals.	Crystallization	from	DMF.	Yield:	70%.	M.p.:	
>	 320	 °C.	 FT‐IR	 (KBr,	 v,	 cm−1):	 3428,	 3338	 (NH2),	 3026	 (CH‐
aromatic),	2918	(CH‐aliphatic),	2188	(CN),	1702	(CO).	1H	NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	9.01	(s,	1H,	=CH),	8.48,	8.22	(2d,	J	
=	 8.1	 Hz,	 2H,	 Ar‐H),	 7.81	 (d,	 J	 =	 7.2,	 2H,	 Ar‐H),	 7.99‐7.19	 (m,	
13H,	Ar‐H),	4.72	(s,	2H,	CH2Ph),	5.60	(br,	2H,	NH2,	exchangeable	
by	D2O),	 4.50	 (s,	 1H,	 pyridine),	 3.72	 (s,	 3H,	 CH3),	 3.70	 (s,	 3H,	
CH3).	MS	 (m/z	 (%)):	 643	 (M+,	 0.9),	 615	 (1.1),	 579	 (4.1),	 476	
(10.0),	408	(11.5),	299	(13.6),	148	(11.9),	91	(100).	Anal.	calcd.	
for	C39H29N7OS:	C,	72.76;	H,	4.54;	N,	15.23.	Found:	C,	72.56;	H,	
4.32;	N,	15.05%.	



El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	 17	
 

	
Table	1.	Antimicrobial	activity	of	the	new	compounds.	

Minimum	inhibitory	concentration	(MIC)	in	μg/mL 

Compound 
Fungi	Gram‐positive	bacteria	Gram‐negative	bacteria	

P.C.	Thom	
(AUCC‐530)	

A.O.	Wilhelm		
(AUCC‐230)	

Staphylococcus
(MTCC	96)	

B.	sphaericus
(MTCC	11)	

B.	subtilis	
(MTCC	441)	

B.	cereus
(ATGG	14579)	

E.	coli	
(NCTC‐10410)	

P.	aeruginosa		
(MTCC	741)	

‐‐ 200	500	200	500	500	500	2	
‐	‐	500	250	500	500 250500	3	
100	125	25	50	25	50	25	25	4	
500‐	250250500250	500200	5	
500	‐	200	250	500	200	200	250	6a	
‐‐	250500500500	250500	6b	
‐	‐	250	500	250	200	500	500	6c	
250	500	200	250	200	250	200	200	6d	
‐	‐	500	250	500	500	200	250	7	
‐	‐	5025	25	50	50	25	8	
500‐	500500250200	500500	9a	
‐‐	500200250250	500500	9b	
250‐	2510010025	25	50	10a	
100100	50255050	10025	10b 
‐‐	500500200250	250250	11	
‐‐	2525100100	50	50	12	
‐	‐	500	250	500	200	200	250	13	
‐	‐	500	200	500	500	250	500	14	
‐‐	500500250500	500500	15	
100	125	5050	25	50	25	25	16	
‐‐	250	500	200	250	500	500	17	
‐‐ 200500500500	250250	18	
100125 50502550	25	25	19	
100100 25505025	50	50	20	
500‐	1001002525	25	25	21	
100100	505010050	25	100	22	
‐‐	6.256.256.256.25	6.25	6.25	Ampicillin	
31.2531.25	‐‐‐‐	‐	‐	Mycostatin	

	

	
2.15.	Antimicrobial	assay		
	

The	 antimicrobial	 activity	 of	 the	 newly	 synthesized	
compounds	2‐22	were	evaluated	against	two	species	of	Gram‐
negative	 bacteria	 Pseudomonas	 aeruginosa	 (MTCC	 741)	 and	
Escherichia	 coli	 (NCTC‐10410);	 four	 Gram‐positive	 bacteria,	
Bacillus	 cereus	 (ATGG	 14579),	 Bacillus	 subtilis	 (MTCC	 441),	
Bacillus	 sphaericus	 (MTCC	11)	 and	Staphylococcus	 (MTCC	96);	
and	two	fungus,	Aspergillus	ochraceus	Wilhelm	(AUCC‐230)	and	
Penicillium	 chrysogenum	 Thom	 (AUCC‐530)	 strains	 by	 disk	
diffusion	 method.	 Ampicillin	 and	 Mycostatin	 were	 used	 as	
standard	drugs	for	the	bacteria	and	fungi,	respectively	[27,28].	
Preliminary	screening	of	phthalazine	derivatives	and	standard	
drugs	 was	 performed	 at	 fixed	 concentrations	 of	 500	 μg/mL.	
Inhibition	 was	 recorded	 by	 measuring	 the	 diameter	 of	 the	
inhibition	 zone	 at	 the	 end	 of	 24	 h	 for	 bacteria	 and	 72	 h	 for	
fungi.	 Each	 experiment	 was	 repeated	 twice.	 Based	 on	 the	
results	 of	 zone	 of	 inhibition,	 the	 minimum	 inhibitory	
concentration	 (MIC)	 of	 compounds	 2‐22	 against	 all	 bacterial	
and	 fungal	 strains	was	 determined	 by	 liquid	dilution	method.	
Stock	solutions	of	 tested	compounds	with	500,	250,	200,	100,	
50,	 25,	 12.5,	 and	 6.25	 μg/mL	 concentrations	 were	 prepared	
with	DMSO	solvent.	The	solutions	of	standard	drugs,	Ampicillin	
and	Mycostatin	are	used	in	the	same	concentrations.	Inoculums	
of	 the	 bacterial	 and	 fungal	 culture	 were	 also	 prepared.	 To	 a	
series	of	tubes	containing	1	mL	each	of	phthalazine	compound	
solution	 with	 different	 concentrations	 and	 0.2	 mL	 of	 the	
inoculums	 was	 added.	 Further	 3.8	 mL	 of	 sterile	 water	 was	
added	to	each	of	the	test	tubes.	These	test	tubes	were	incubated	
for	 24	 h	 at	 37	 oC	 and	 observed	 for	 the	 presence	 of	 turbidity.	
This	method	was	repeated	by	changing	phthalazine	compounds	
with	standard	drugs	Ampicillin	and	Mycostatin	for	comparison.	
The	minimum	inhibitory	concentration	at	which	no	growth	was	
observed	was	taken	as	the	MIC	value	(Table	1).	
	
3.	Results	and	discussion	
	
3.1.	Synthesis	

	
Treatment	 of	 4‐benzyl‐1‐chlorophthalazine	 (1)	 [25]	 with	

thiosemicarbazide	 furnished	 4‐benzylphthalazin‐1‐ylthiol	 (2).	

While	 interaction	 of	 compound	1	with	 thiocarbohydrazide,	 4‐
benzylphthalazin‐1‐ylamine	(3)	was	 the	only	 isolable	product.	
The	 formation	of	 these	products	2	and	3	pointed	out	 that	 the	
less	negative	atom	(S	in	case	of	thiosemicarbazide	and	terminal	
N	in	case	of	thiocarohydrazide)	attacks	the	electrophilic	carbon	
attached	to	Cl	and	=	N	groups	(Scheme	1).	

Interaction	 of	 (4‐benzyl‐1‐oxo‐1H‐phthalazin‐2‐yl)acetic	
acid	 hydrazide	 [26]	 with	 compound	 1	 afforded	 the	 corres‐
ponding	 4‐benzyl‐2‐((6‐benzyl[1,2,4]‐triazolo‐[3,4‐a]phthal‐
azin‐3‐yl)methyl)phthalazin‐1(2H)‐one	(4)	(Scheme	1).	

The	structure	of	compounds	2‐4	were	confirmed	by	IR,	1H	
NMR,	13C	NMR	and	MS.	The	IR	spectra	of	compound	2	showed	ν	
at	2908	cm‐1	(SH),	for	compound	3	showed	ν	at	3274,	3204	cm‐

1	 (NH2),	 1640	 cm‐1	 (C=N),	 respectively.	 1H	 NMR	 spectra	 of	
compound	2	showed	δ	at	8.61	(brs,	1H,	NH),	14.32	(s,	1H,	SH),	
for	compound	3	showed	δ	at	4.48	(brs,	2H,	NH2),	for	compound	
4	 indicates	 that	 its	 structure	 is	 a	mixture	 of	 three	 tautomeric	
forms	(A)	 ,	 (B)	and	(C)	 in	different	contributions	showed	δ	 at	
11.14,	11.35	(2s,	1H,	NH),	10.13,	9.93	(2s,	1H,	NH),	respectively.	

13C	NMR	spectra	of	compound	4	 showed	δ	at	167.77	(CO),	
52.31	 (NCH2C),	 37.66,	 37.56	 (CH2Ph).	 The	 mass	 spectra	 of	
compounds	2‐4	showed	the	corresponding	molecular	ion	peaks	
at	m/z	=	252	(M+,	83.8),	m/z	=	235	(M+,	4.6)	and	m/z	=	508	(M+,	
95.6),	respectively.		

Reaction	of	compound	1	with	cyanoacetohydrazide	to	give	
the	 corresponding	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐
yl)acetonitrile	 (5).	 Treatment	 of	 compound	 5	 with	 aromatic	
aldehydes	in	boiling	ethanol	in	the	presence	of	piperidine	as	a	
catalyst	 afforded	 the	 corresponding	 triazolophthalazin‐3‐
ylacrylonitrile	 derivatives,	 6a‐d	 (Scheme	 2).	 The	 structure	 of	
compounds	5	and	6	were	confirmed	by	IR,	1H	NMR	and	MS.		

Condensation	 of	 compound	 5	 with	 phenolic	 aldehydes	
(salicylaldehyde,	 2‐hydroxy‐1‐naphthaldehyde	 and	 2,7‐
dihydroxy‐1‐naphthaldehyde)	 under	 Knoevenagel	 reaction	
conditions	 afforded	 3‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthal‐
azin‐3‐yl)‐2H‐chromen‐2‐imine	 (7),	 2‐(6‐benzyl[1,2,4]triazolo	
[3,4‐a]phthalazin‐3‐yl)‐3H‐benzo[f]chromen‐3‐imine	 (9a)	 and	
2‐(6‐benzyl[1,2,4]triazolo‐[3,4‐a]phthalazin‐3‐yl)‐3‐imino‐3H‐
benzo[f]chromen‐9‐ol	(9b),	respectively	(Scheme	3).	Refluxing	
compound	7	and	9a,b	in	glacial	acetic	acid/sodium	acetate	gave	



18	 El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	
	
3‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐chromen‐2‐
one	 (8),	 2‐(6‐benzyl[1,2,4]triazolo‐[3,4‐a]phthalazin‐3‐yl)‐3‐
imino‐3H‐benzo[f]chromen‐9‐ol	 (9b)	 and	 2‐(6‐benzyl[1,2,4]	
triazolo[3,4‐a]phthala‐zin‐3‐yl)‐9‐hydroxybenzo[f]chromen‐3‐
one	(10b),	respectively	(Scheme	3).	

The	structure	of	compounds	7‐10	were	confirmed	by	IR,	1H	
NMR	and	MS.	The	IR	spectra	of	compound	7	showed	ν	at	3228	
cm‐1	 (NH),	 for	 compound	 8	 showed	 ν	 at	 1732	 cm‐1	 (CO),	 for	
compound	9b	showed	ν	at	3280	cm‐1	(NH),	3476	cm‐1	(OH),	for	
compound	 10a	 showed	 ν	 at	 1726	 cm‐1	 (CO),	 compound	 10b	
showed	ν	at	3452	cm‐1	(OH),	1720	cm‐1(CO).	1H	NMR	spectra	of	
compound	7	 showed	δ	at	10.20	(s,	1H,	NH),	 for	compound	9a	
showed	δ	 at	10.03	 (s,	1H,	NH),	 for	 compound	9b	 showed	δ	 at	
10.09	(brs,	1H,	NH),	9.42	(brs,	1H,	OH),	respectively.	The	mass	
spectra	 of	 compounds	 8	 and	 10a,b	 and	 showed	 the	
corresponding	molecular	ion	peaks	at	m/z	=	404	(M+,	100),	m/z	
=	454	(M+,	100),	m/z	=	470	(M+,	3.09),	respectively.	

Since,	compound	5	contains	very	reactive	methylene	group,	
so,	this	derivative	underwent	coupling	with	equimolar	amount	
of	p‐tolyldiazonium	chloride	 in	 ethanol	 and	sodium	acetate	 at	
(0‐5	°C),	to	afford	a	colored	product	which	was	identified	as	(6‐
benzyl‐N'‐(p‐tolyl)‐[1,2,4]triazolo[3,4‐a]phthalazine‐3‐carbo‐
hydrazonoyl	 cyanide	 (11).	 In	 the	 same	 manner,	 triazolo‐
phthalazin‐3‐ylacetonitrile	(5)	couples	with	a	buffered	solution	
of	 1H‐[1,2,4]triazolo‐3‐yldiazonium	 chloride	 to	 afford	 the	
corresponding	 (6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐
[(4H‐[1,2,4]triazolo‐3‐yl)hydrazono]acetonitrile	 (12)	 (Scheme	
4).	

The	structure	of	compounds	11	and	12	were	confirmed	by	
IR,	1H	NMR	and	MS.	The	IR	spectra	of	compound	11	showed	ν	
at	3082	cm‐1	(NH),	2220	cm‐1	(CN),	for	compound	12	showed	ν	
at	 3076	 cm‐1	 (NH,	 br),	 2224	 cm‐1	 (CN),	 respectively.	 1H‐NMR	
spectra	of	compound	12	showed	δ	at	14.00,	13.60	(s,	2H,	NH),	
12.60	 (s,	 1H,	 triazolo‐H).	 The	mass	 spectra	 of	 compounds	11	
and	12	and	showed	the	corresponding	molecular	 ion	peaks	at	
m/z	=	417	(M+,	13.1),	m/z	=	394	(M+,	61.9),	respectively.	

Reaction	 of	 compound	 5	 with	 triethyl‐orthoformate	 in	
boiling	acetic	anhydride	 to	give	2‐(6‐benzyl[1,2,4]triazolo[3,4‐
a]phthalazin‐3‐yl)‐3‐ethoxyacrylonitrile	 (13)	and	 treatment	of	
compound	 13	 with	 hydroxylamine	 hydrochloride	 in	 boiling	
ethanol‐fused	 sodium	acetate	 gave	3‐amino‐2‐(6‐benzyl[1,2,4]	
triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐(hydroxyimino)prop‐1‐enyl	
acetate	(14).	The	formation	of	compound	14	can	be	attributed	
to	 the	 nucleophilic	 addition	 of	 NH2OH	 to	 the	 CN	 group	 and	
nucleophilic	 exchange	 of	 the	 ethoxy	 group	 by	 the	 acetoxy	
nucleophile.	 Compound	 13	 undergoes	 cycloaddition	 with	
thiourea	 to	 furnished	 the	corresponding	4‐amino‐5‐(6‐benz‐yl	
[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐1H‐pyrimidine‐2‐thione	
(15)	(Scheme	5).	Similarly,	compound	5	reacted	with	3‐amino‐
1,2,4‐triazole	 to	 yield	 the	 corresponding	 6‐(6‐benzyl[1,2,4]	
triazolo[3,4‐a]phthalazin‐3‐yl)‐8H‐[1,2,4]triazolo[4,3‐a]pyrimi‐
din‐5‐ylideneamine	(16)	(Scheme	5).	

The	structure	of	compounds	13‐16	were	confirmed	by	 IR,	
1H	 NMR	 and	 MS.	 The	 IR	 spectrum	 of	 compound	 13	 showed	
absorptions	 at	 2256	 cm−1	 (CN),	 while	 for	 compound	 14	 the	
characteristic	bands	were	at	3382	cm−1	(OH),	3284,	3192	cm−1	
(NH2),	 compound	 16	 at	 1602,	 1632	 cm−1	 (C=N),	 3184	 cm−1	
(NH),	and	compound	15	at	1640	cm−1	(C=S),	3244	cm−1	(NH2),	
3056	 cm−1	 (NH),	 respectively.	 The	 1H‐NMR	 of	 compound	 13	
showed	 characteristic	 signals	 at	δ	 1.310	 (t,	 3H,	 CH2CH3),	 4.28	
(q,	2H,	CH2CH3),	CH2Ph	 (4.72,	 singlet	 signal),	 (7.19‐8.53)	 (sets	
of	multiplets,	9H,	Ar‐H),	8.25	(s,	1H,	=CH),	The	mass	spectra	of	
compounds	 14‐16	 showed	 the	 corresponding	 molecular	 ion	
peaks	m/z	 =	 402	 (M+,	 100),	m/z	 =	 385	 (19.4)	 and	m/z	 =	 393	
(M+,	51.4),	respectively.		

Treatment	 of	 3‐ethoxyacrylonitrile	 derivative	 (13)	 with	
hydrazine	 hydrate	 in	 ethanol	 at	 room	 temperature	 was	
unsuccessful,	 while	 when	 under	 reflux,	 the	 reaction	 was	
successful	 and	 the	 reaction	product	was	 identified	 as	 ethyl	 3‐
amino‐2‐(6‐benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐
hydrazonopropane	hydrazonate	(17).		

The	 formation	 of	 such	 compound	 indicated	 that	 the	
reaction	 proceeds	 through	 nucleophilic	 addition	 of	 two	
hydrazine	molecules	to	the	vinyl	and	the	nitrile	groups	leading	
to	 the	 formation	 of	 non‐isolable	 intermediate	 (A),	 which	 in	
turn,	 undergoes	 spontaneous	 dehydrogenation	 rather	 than	
elimination	 of	 ethanol	 molecule	 to	 give	 compound	 17	 as	 the	
only	isolable	product	(Scheme	6).	

Also,	 treatment	 of	 compound	 13	 with	 ethanolic	
phenylhydrazine	 under	 the	 conditions	 of	 reflux	 gave	 the	
isolable	 product	 which	 was	 identified	 as	 2‐(6‐benzyl‐
[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐3‐ethoxy‐3‐(2‐phenyl	
hydrazinyl)acrylonitrile	 (18).	 The	 formation	 of	 this	 product	
could	 be	 explained	 through	 nucleophilic	 addition	 of	 one	
phenylhydrazine	molecule	to	vinyl	group	followed	by	oxidation	
of	the	intermediate	(B)	to	the	final	product	(Scheme	6).		

The	structure	of	compounds	17	and	18	were	confirmed	by	
IR	 and	 MS.	 The	 IR	 spectrum	 of	 compound	 17	 showed	
absorptions	 at	 3198	 cm−1	 (NH),	 1598	 cm−1	 (C=N),	 while	 for	
compound	 18	 showed	 absorptions	 at	 3212	 (NH),	 2198	 cm−1	
(CN).	 The	mass	 spectra	 of	 compounds	17	and	18	showed	 the	
corresponding	 molecular	 ion	 peaks	m/z	 (%):	 417	 (M+,	 32.6)	
and	461	(M+,	100),	respectively.	

Treatment	of	compound	5	with	thioglycolic	acid,	the	given	
reaction	 in	 Scheme	 7	 would	 occur,	 where	 2‐(6‐benzyl[1,2,4]	
triazolo[3,4‐a]phthalazin‐3‐ylmeth‐yl)thiazol‐4‐one	 (19)	 is	
formed.	 Condensation	 of	 19	 with	 anisaldehyde	 in	 boiling	
ethanol/piperidine	 gave	 the	 corresponding	 2‐((6‐benzyl‐
[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)methyl)‐5‐(4‐
methoxybenzylidene)thiazol‐4‐one	(20)	(Scheme	7).	

The	structure	of	compounds	19	and	20	were	confirmed	by	
IR,	1H	NMR	and	MS.	The	IR	spectrum	of	compound	19	showed	
absorptions	at	1726	cm−1	(CO),	while	for	compound	20	showed	
absorptions	 at	1682	 cm−1	 (CO).	 1H	NMR	spectra	 of	 compound	
19	showed	δ	at	11.43	(s,	1H,	OH,	exchangeable	by	D2O),	6.45	(s,	
1H,	CH‐thiazolidinone),	for	compound	20	showed	δ	at	9.	01	(s,	
1H,	=CH),	3.74	 (s,	3H,	OCH3).	The	mass	spectra	of	compounds	
19	and	20	showed	the	corresponding	molecular	ion	peaks	m/z	
=	373	(M+,	13.1)	and	491	(M+,	95.1),	respectively.	

Treatment	of	compound	19	with	a	mixture	of	malononitrile	
and	 p‐anisalodehyde	 in	 equimolar	 ratio	 in	 boiling	 ethanol‐
piperidine	 was	 successful	 and	 the	 corresponding	 2‐(6‐
benzyl[1,2,4]triazolo[3,4‐a]phthalazin‐3‐ylmethyl)‐5‐oxo‐6,7‐
dihydro‐7‐(4‐methoxyphenyl)‐5H‐pyrano[2,3‐d]thiazole‐6‐
carbonitrile	 (21).	 The	 formation	 of	 compound	 21	 can	 be	
rationalized	 by	 addition	 of	 active	 methylene	 group	 of	 4‐
thiazolinone	 19	 at	 the	 activated	 ethylenic	 double	 bond	 of	
benzylidene	 malononitrile	 forming	 an	 adduct	 (A)	 which	
undergoes	 intramolecular	 cyclization	 and	 spontaneous	
hydrolysis	of	the	imino	function	into	the	carbonyl	group	under	
the	 experimental	 reaction	 conditions	 employed	 (Scheme	 8).	
Compound	19	reacted	with	malononitrile	and	p‐tolaldehyde	in	
boiling	ethanol‐piperidine	in	molar	ratio	1:1:2	to	give	5‐amino‐
8‐(6‐benzyl‐[1,2,4]triazolo[3,4‐a]phthalazin‐3‐yl)‐2‐(4‐methyl	
benzylidene)‐3‐oxo‐7‐(p‐tolyl)‐3,7‐dihydro‐2H‐thiazolo[3,2‐a]	
pyridine‐6‐carbonitrile	(22).	The	formation	of	compound	22	is	
rationalized	by	the	condensation	of	two	molecules	of	aromatic	
aldehyde	 with	 4‐thiazolinone	 and	 malononitrile,	 respectively	
followed	 by	 the	 nucleophilic	 addition	 of	 methylene	 bridge	 of	
the	1st	derivative	to	the	activated	ethylenic	double	bond	of	the	
second	 one	 and	 the	 formed	 adduct	 (B)	 undergoes	
intramolecular	cyclization	into	the	final	product	22	(Scheme	8).		

The	structure	of	compounds	21	and	22	were	confirmed	by	
IR,	1H	NMR	and	MS.	The	IR	spectrum	of	compound	21	showed	
absorptions	at	2190	(CN),	1690	cm−1	(CO),	while	for	compound	
22	 showed	 absorptions	 at	 2188	 (CN)	 and	 1702	 cm−1	 (CO),	
respectively.	The	1H	NMR	of	compound	21	showed	δH	8.42	(d,	
1H,	Ar‐H),	8.25	(d,	1H,	Ar‐H),	7.97‐	7.66	(m,	11H,	Ar‐H),	5.38	(s,	
2H,	CH2Ph),	4.72,	4.63	 (2d,	3H,	4H‐pyran),	3.78	 (s,	 2H,	 ‐CH2‐),	
3.58	(s,	3H,	OCH3).	The	mass	spectra	of	compound	22	showed	
the	corresponding	molecular	ion	peak	m/z	=	643	(M+,	0.9).		
	



El‐Wahab	et	al.	/	European	Journal	of	Chemistry	4	(1)	(2013)	10‐19	 19	
 

3.2.	Antimicrobial	activity	
	

The	 antimicrobial	 activity	 of	 the	 newly	 synthesized	
compounds	2‐22	were	evaluated	against	two	species	of	Gram‐
negative	 bacteria	 Pseudomonas	 aeruginosa	 (MTCC	 741);	
Escherichia	 coli	 (NCTC‐10410);	 and	 four	 Gram‐positive	
bacteria,	Bacillus	cereus	(ATGG	14579);	Bacillus	subtilis	(MTCC	
441);	 Bacillus	 sphaericus	 (MTCC	 11);	 Staphylococcus	 (MTCC	
96);	and	two	fungus,	Aspergillus	ochraceus	Wilhelm	(AUCC‐230)	
and	Penicillium	chrysogenum	Thom	(AUCC‐530)	strains	by	disk	
diffusion	 method.	 Ampicillin	 and	 Mycostatin	 were	 used	 as	
standard	drugs	for	the	bacteria	and	fungi,	respectively.		

The	 comparison	 of	 the	 MICs	 (in	 μg/mL)	 of	 potent	
compounds	 and	 standard	 drugs	 against	 tested	 strains	 are	
presented	 in	 the	 (Table	 1).	 Investigation	 of	 the	 antibacterial	
screening	data	(Table	1)	showed	that	some	of	 the	compounds	
were	active	against	some	pathogenic	bacteria.	Compounds	4,	8,	
10b,	 16,	 19	 and	 21	 exhibited	 good	 activity	 against	
Pseudomonas	aeruginosa,	while	compounds	4,	10a,	16,	19,	21	
and	 22	 exhibited	 good	 activity	 against	 Escherichia	 coli	 and	
compounds	 10a,	 20	 and	 21	 exhibited	 good	 activity	 against	
Bacillus	 cereus.	 In	 addition,	 compounds	 4,	 8,	 16,	 19	 and	 21	
exhibited	good	activity	against	Bacillus	subtilis	and	compounds	
8,	 10b	 and	 12	 exhibited	 good	 activity	 against	 Bacillus	
sphaericus,	while	compounds	4,	10a,	12	and	20	exhibited	good	
activity	against	Staphylococcus.	

The	 antifungal	 results	 (Table	 1)	 revealed	 that	 the	
synthesized	compounds	showed	variable	degrees	of	 inhibition	
against	the	tested	fungi.	Compounds	4,	10b,	16,	19,	20	and	22	
possessed	 moderate	 antifungal	 activity	 against	 Aspergillus	
ochraceus	Wilhelm	and	Penicillium	chrysogenum	Thom.	
	
4.	Conclusion	
	

Our	 interest	 in	 synthesis	 of	 heterocyclic	 compounds	 is	 to	
focus	 on	 their	 antimicrobial	 activity	 as	 a	 part	 of	 our	program	
which	 aimed	 at	 the	 development	 of	 new	 and	 more	 potent	
antimicrobial	 agents.	 Thus,	 in	 this	 paper,	 we	 revealed	 the	
synthesis	 of	 some	 triazolophthalazine	 derivatives	 and	
antimicrobial	 evaluation	 of	 all	 the	 novel	 compounds.	 The	
structures	 of	 the	 novel	 compounds	 were	 elucidated	 on	 the	
basis	 of	 IR,	 1H	NMR,	 13C	 NMR	 and	MS	 data.	 A	 series	 of	 novel	
triazolophthalazine	 derivatives	 were	 prepared.	 The	
antimicrobial	 activity	 of	 these	 compounds	 was	 evaluated	
against	 various	 Gram‐positive,	 Gram‐negative	 bacteria	 and	
fungi.	 Triazolophthalazine	 and	 triazolophthalazinethiazole	
derivatives	 are	 strong	 activities	 against	 any	 of	 the	 test	
microorganisms.	
	
References	
	
[1]. Juan,	 L.;	 Yan‐Fang,	 Z.;	 Yuan,	 Xiao‐Ye,	 Y.;	 Jing‐Xiong,	 X.;	 Ping,	 G.	

Molecules	2006,	11,	574‐582.		
[2]. Jin,	 S.	 K.;	 Hee‐Kyung,	 R.;	 Hyen,	 J.	 P.;	 Sang,	 K.	 L.;	 Chong‐Ock,	 L.;	 Hea‐

Young,	P.	C.	Bioorg.	Med.	Chem.	2008,	16,	4545‐4550.		
[3]. Raposo,	M.	M.;	Sampaio,	A.	M.	B.	A.;	Kirsch,	G.	 J.	Hetero.	Chem.	2005,	

42,	1245‐1451.		
[4]. Haack,	T.;	Fattori,	R.;	Naboletano,	M.;	Pellacini,	F.;	Fronza,	G.;	Raffaini,	

G.;	Janazzoli,	F.	Bioorg.	Med.	Chem.	2005,	13,	4425‐4433.		
[5]. Napoletano,	M.;	 Norcini,	 G.;	 Pellacini,	 F.;	Marchini,	 F.;	Morazzoni,	 G.;	

Fattori,	R.;	Ferienga,	P.;	Pradella,	L.	Bioorg.	Med.	Chem.	Lett.	2002,	12,	
5‐8.		

[6]. Napoletano,	M.;	 Norcini,	 G.;	 Pellacini,	 F.;	Marchini,	 F.;	Morazzoni,	 G.;	
Fattori,	R.;	Ferienga,	P.;	Pradella,	L.	Bioorg.	Med.	Chem.	Lett.	2001,	11,	
33‐37.		

[7]. Line,	 B.;	 Andre,	 T.;	 Patricia,	 M.	 Tertrahedron	 Lett.	 1996,	 37,	 4145‐
4148.		

[8]. Reddy,	R.	 S.;	 Saravanan,	K.;	Kumar,	P.	Tertrahedron	1998,	54,	 6553‐
6564.		

[9]. Gomha,	S.	M.;	Riyadh,	S.	M.	Molecules	2011,	16,	8244‐8256.		
[10]. El‐Sakka,	S.	S.;	Soliman,	A.	H.;	Imam,	A.	M.	Afinidad	2009,	66,	167‐172.		
[11]. Tsoungas,	P.	G.;	Searcey,	M.	Tetrahedron	Lett.	2001,	42,	6589‐6592.		
[12]. Sivakumar,	R.;	Gnanasam,	S.	K.;	Ramachandran,	S.;	Leonard,	J.	T.	Eur.	J.	

Med.	Chem.	2002,	37,	793‐801.		

[13]. Coelho,	 A.;	 Sotelo,	 E.;	 Fraiz,	 N.	 M.;	 Yanez,	 M.;	 Laguna,	 R.;	 Canob,	 E.;	
Ravina,	E.	Bioorg.	Med.	Chem.	Lett.	2004,	14,	321‐324.		

[14]. Demirayak,	S.;	Karaburun,	A.	C.;	Beis,	R.	Eur.	 J.	Med.	Chem.	2004,	39,	
1089‐1095.		

[15]. Dogruer,	D.	S.;	Sahin,	M.	F.;	Unlu,	S.;	Ito,	S.	Arch.	Pharm.	2000,	333,	79‐
86.		

[16]. Norbert,	H.;	 Tamara,	 K.;	 Johann,	 K.;	 Angelika,	 P.	Molecules	2007,	12,	
1900‐1909.		

[17]. Imamura,	Y.;	Noda,	A.;	Imamura,	T.;	Ono,	Y.;	Okawara,	T.;	Noda,	H.	Life	
Sci.	2003,	74,	29‐36.		

[18]. Dogruer,	D.	S.;	Sahin,	M.	F.;	Kupeli,	E.;	Yesilada,	E.	Turk.	J.	Chem.	2003,	
27,	727‐738.		

[19]. Dogruer,	D.	S.;	Sahin,	M.	F.;	Kupeli,	E.;	Yesilada,	E.	Arch.	Pharm.	2004,	
337,	303‐310.		

[20]. Bold,	G.;	Altmann,	K.	 ‐H.;	Frei,	 J.;	Lang,	M.;	Manley,	P.	W.;	Traxler,	P.;	
Wietfeld,	B.;	Brueggen,	J.;	Buchdunger,	E.;	Cozens,	R.;	Ferrari,	S.;	Furet,	
P.;	 Hofmann,	 F.;	 MartinyBaron,	 G.;	 Mestan,	 J.;	 Roesel,	 J.;	 Sills,	 M.;	
Stover,	D.;	Acemoglu,	F.;	Boss,	E.;	Emmenegger,	R.;	Laesser,	L.;	Masso,	
E.;	 Roth,	R.;	 Schlachter,	 C.;	 Vetterli,	W.;	Wyss,	 D.;	Wood,	 J.	M.	 J.	Med.	
Chem.	2000,	43,	2310‐2323.		

[21]. Stuart,	 L.	 F.;	 Daniel,	 F.	 M.;	 Peter,	 K.	Nature	 Reviews	Drug	Discovery,	
2005,	4,	187‐188.		

[22]. Hennequin,	L.	F.;	 Stokes,	E.	S.;	Thomas,	A.	P.;	 Johnstone,	C;	Ple,	P.	A.;	
Ogilvie,	D.	J.;	Dukes,	M.;	Wedge,	S.	R.;	Kendrew,	J.;	Curwen,	J.	O.	J.	Med.	
Chem.	2002,	45,	1300‐1312.		

[23]. Piatnitski,	E.	L.;	Duncton,	M.	A.;	Kiselyov,	A.	S.;	Katoch,	R.	R.;	Sherman,	
D.;	Milligan,	D.	L.;	Balagtas,	C.;	Wong,	W.	C.;	Kawakami,	J.;	Doody,	J.	F.	
Bioorg.	Med.	Chem.	Lett.	2005,	15,	4696‐4698.		

[24]. Matthew,	A.	 J.	D.;	Evgueni,	L.	P.;	Reeti,	K.	R;	Leon,	M.	S.;	Alexander,	S.	
K.;	Daniel,	L.	M.;	Chris,	B;	Wai,	C.	W.;	 Joel,	K.;	 Jacqueline,	F.	D.	Bioorg.	
Med.	Chem.	Lett.	2006,	16,	1579‐1581.		

[25]. Bromber,	A.	Ber.	1896,	29,	1434‐1435.		
[26]. Ashraf,	H.	F.	A;	Hany,	M.	M.;	Ahmed,	M.	E;	Mohammed,	A.	E.;	Ahmed,	H.	

B.	Pharmaceuticals	2011,	4,	1158‐1170		
[27]. European	 Committee	 for	 Antimicrobial	 Susceptibility	 Testing	

(EUCAST)	 of	 the	 European	 Society	 of	 Clinical	 Microbiology	 and	
Infectious	Diseases	 (ESCMID).	Determination	 of	minimum	 inhibitory	
concentrations	 (MICs)	 of	 antibacterial	 agents	 by	 agar	 dilution.	 Clin.	
Microbiol.	Infect.	2000,	6,	509‐515.		

[28]. National	 Committee	 for	 Clinical	 Laboratory	 Standards.	 Methods	 for	
Dilution	 Antimicrobial	 Susceptibility	 Tests	 for	 Bacteria	 that	 Grow	
Aerobically,	 5th	 ed.;	 NCCLS:	 Wayne,	 PA,	 USA,	 2000;	 Approved	
Standard	M7‐A5.