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European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	

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

DOI:10.5155/eurjchem.4.2.138‐145.749	

	
	

	

	

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

	 	 	

An	efficient	synthesis	of	some	new	isolated	and	fused		
2‐oxo‐2H‐chromene	derivatives	as	antimicrobial	and	antitumor	agents	

Hafez	Mohamed	El‐Shaaer	*	

Department	of	Chemistry,	Faculty	of	Education,	Ain	Shams	University,	Roxy,	11711,	Cairo,	Egypt	

*Corresponding	author	at:	Department	of	Chemistry,	Faculty	of	Education,	Ain	Shams	University,	Roxy,	11711,	Cairo,	Egypt.		
Tel.:	+2.02.01112627069;	fax:	+2.02.2581243.	E‐mail	address:	elshaaer@hotmail.com	(H.	M.	El‐Shaaer).	

	
	

	 	

	 	 	
ARTICLE	INFORMATION	 	 ABSTRACT
Received:	14	February	2013	
Received	in	revised	form:	28	March	2013	
Accepted:	30	March	2013	
Online:	30	June	2013	

KEYWORDS	

	 An	efficient	synthesis	of	the	biologically	active	novel	systems	derived	from	the	reaction	of	4‐
methyl‐2‐oxo‐2H‐chromene‐3‐carbonitrile	(1)	with	sodium	hydroxide	and/or	DMF‐DMA	and
cyclocondensation	 reactions	 of	 4‐[(E)‐2‐(dimethylamino)ethenyl]‐2‐oxo‐2H‐chromene‐3‐
carbonitrile	 (5)	 with	 nitrogen	 nucleophilic	 reagents	 afforded	 the	 corresponding	 4‐
iminochromeno[3,4‐c]pyridine	derivatives	(6‐14).	The	structures	of	the	prepared	compounds
have	 been	proved	 by	 elemental	 analysis,	 IR,	 1H	 	 and	 13C	NMR	and	mass	 spectra.	 Significant
antitumor	activities	in	planta	were	observed	for	some	of	the	prepared	compounds.	

Synthesis	
Antitumor	activity	
Cyclocondensation	
2‐Oxo‐2H‐chromene	
Antimicrobial	Activity	
Chromeno[3,4‐c]pyridin‐5‐ones	

	
1.	Introduction	
	

Fused	 and	 isolated	 2‐oxo‐2H‐chromenes	 (coumarins)	
comprise	 a	 very	 interesting	 class	 of	 compounds	 due	 to	 their	
significant	antibacterial	[1],	antifungal	[2‐4],	antimycobecterial	
[5,6],	 anticoagulants	 [7,8],	 inhibition	 of	 some	 enzymes	 [9,10]	
and	antitumor	[11‐13]	activities.	With	the	expectations	to	find	
biological	 activity,	 we	 decided	 to	 investigate	 the	 synthesis	 of	
some	novel	systems	of	2‐oxo‐2H‐chromene	derivatives	bearing	
fused	 and	 isolated	 moieties.	 Recently,	 the	 synthesis	 [14],	
photochemical	 [15],	 and	 theoretical	 [2,16‐18]	 properties	 of	
chromene	derivatives	were	investigated.	

The	 aim	of	 the	present	paper	 is	 to	 investigate	 an	 efficient	
synthesis	of	fused	and	isolated	2‐oxo‐2H‐chromene	derivatives	
containing	 active	 methyl	 and	 cyano	 groups	 and	 study	 their	
cyclocondensation	 reactions	 with	 nitrogen	 nucleophilic	
reagents	 such	 as	 hydroxylamine	 hydrochloride,	 urea,	
semicarbazide,	 methylamine	 hydrochloride,	 4‐amino‐1,2,4‐
triazine	 derivative,	 2‐aminoethanol,	 ethane‐1,2‐diamine	 and	
thiosemicarbazide.	 The	 antimicrobial	 and	 antitumor	 activities	
for	the	prepared	compounds	were	investigated.	
	
2.	Experimental	
	
2.1.	Instrumentation	
	

The	uncorrected	melting	point	was	determined	in	an	open	
capillary	tube	on	a	digital	Stuart	SMP‐3	apparatus.	1H	NMR/13C	
NMR	spectra	were	obtained	on	a	500/125	MHz	Jeol	Eca	or	on	a	
300/75.46	MHz	Varian	Mercury	VX‐300	NMR	spectrometer	 in	
DMSO‐d6	 with	 tetramethylsilane	 as	 an	 internal	 standard.	
Elemental	 analyses	 were	 performed	 on	 Vario	 El	 Elementar	
apparatus.	 IR	 spectra	 were	 recorded	 on	 FT‐IR	 Nicolet	 IS10	
spectrophotometer	 (cm‐1),	 using	 KBr	 disks.	 Mass	 spectra	
recorded	on	a	Gas	chromatographic	GCMSqp	1000	ex	Shimadzu	

instrument	 at	 70	 eV.	 4‐Methyl‐2‐oxo‐2H‐chromene‐3‐
carbonitrile	 (1)	 [2],	 4‐amino‐6‐methyl‐3‐thioxo‐3,4‐dihydro‐
1,2,4‐triazin‐5(2H)‐one	 [19]	 were	 prepared	 by	 previously	
reported	 procedures.	 All	 other	 chemicals	 used	 in	 this	 study	
were	commercially	available.	
	
2.2.	Synthesis	
	
2.2.1.	4‐Methyl‐2‐oxo‐2H‐chromene‐3‐carboxylic	acid	(2)		
	

A	solution	of	compound	1	(0.5	g,	0.27	mmol)	in	ethanol	(2	
cm3),	 sodium	hydroxide	 solution	 (0.09	 g	 sodium	hydroxide,	 2	
cm3	ethanol)	was	added	and	the	reaction	mixture	was	refluxed	
with	 stirring	 for	 0.5	 h,	 cooled	 to	 room	 temperature	 and	
acidified	with	dilute	hydrochloric	acid.	The	solid	obtained	was	
filtered	off,	and	recrystallized	from	ethanol	to	give	compound	2	
as	brown	crystals	(Scheme	1).	Yield:	72%.	M.p.:	152‐153	°C.	FT‐
IR	(KBr,	ν,	cm‐1):	3149	(br,	OH),	3006	(CHarom),	1709	(C=Oacid),	
1684	(C=Ocoumarin).	 1H	NMR	(500	MHz,	DMSO‐d6,	δ,	ppm):	2.46	
(s,	3H,	CH3),	7.29	(bs,	1H,	OH),	7.38‐7.47	(m,	2H,	6‐H	and	8‐H),	
7.65	(dd,	J	=	8.4	Hz,	6.8	Hz,	1H,	7‐H),	7.85	(d,	J	=	8.4	Hz,	1H,	5‐
H).	 MS	 (EI,	m/z	 (%)):	 202.15	 (M+‐2,	 1.1),	 203.15	 (M+‐1,	 2.5),	
204.10	(M+,	22.4),	205.10	(M++1,	3.1),	206.10	(M++2,	0.6).	Anal.	
calcd.	for	C11H8O4:	C,	64.71;	H,	3.95.	Found:	C,	64.51;	H,	3.60%.	
	
2.2.2.	N‐[Imino(4‐methy‐2‐oxo‐2H‐chromen‐3‐yl)methyl]‐4‐
methyl‐2‐oxo‐2H‐chromene‐3‐carboxamide	(3)		
		

A	 mixture	 of	 compound	 1	 (0.5	 g,	 0.27	 mmol),	 sodium	
hydroxide	solution	(0.09	g	sodium	hydroxide,	4	cm3	water)	was	
refluxed	with	stirring	for	0.5	h,	then	ethanol	(2	cm3)	was	added	
and	 the	 mixture	 was	 refluxed	 for	 3	 h,	 cooled	 to	 room	
temperature	 and	 filtered	 off.	 The	 solid	 obtained	was	 acidified	
with	dilute	hydrochloric	acid,	stirred	at	room	temperature	for	5	
min,	poured	over	water	(10	cm3),	filtered	off	and	recrystallized	
from	ethanol	to	give	compound	3	as	white	crystals	(Scheme	1).		



El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	 139	
 

 

	

	
	

Scheme	1
	
	

	
	

Scheme	2
	
	
Yield:	67%.	M.p.:	225‐226	°C.	FT‐IR	(KBr,	 ν,	 cm‐1):	3424	(NH),	
3365	 (NH),	 3068	 (CHarom),	 2986,	 2900	 (CHaliph),	 1728	 (br,	
C=Ocoumarin),	 1651	 (C=Oamide).	 1H	 NMR	 (500	 MHz,	 DMSO‐d6,	 δ,	
ppm):	2.46	(bs,	6H	,	CH3),	6.99	(bs,	1H,	Ar‐H),	7.37‐7.43	(m,	3H,	
Ar‐H),	 7.59‐7.64	 (m,	 1H,	 Ar‐H),	 7.77‐7.82	 (m,	 1H,	 Ar‐H),	 8.21	
(bs,	 1H,	 Ar‐H),	 8.28	 (bs,	 1H,	 Ar‐H),	 11.06	 (s,	 1H,	 =NH)	 (NH	
amide	proton	was	displaced	due	to	hydrogen	bonding).	MS	(EI,	
m/z	 (%)):	387.80	 (M+,	75.0),	 388.80	 (M++1,	54.1).	Anal.	 calcd.	
for	 C22H16N2O5:	 C,	 68.04;	 H,	 4.15;	 N,	 7.21.	 Found:	 C,	 68.30;	 H,	
4.01;	N,	7.45%.	
	
2.2.3.	4‐(1‐Ethoxy‐2‐oxoethyl)‐2‐oxo‐2H‐chromene‐3‐
carbonitrile	(4)		
	

Phosphorus	oxychloride	 (1.2	 cm3)	was	added	dropwise	 to	
DMF	(2.7	cm3)	with	stirring	at	30‐35	°C,	after	the	addition	was	
completed,	 the	 solution	was	stirred	at	50‐60	 °C	 for	30	min.	A	
solution	of	 compound	1	 (0.5	g,	0.27	mmol)	 in	dry	pyridine	 (2	
cm3)	was	added	to	the	above	mixture	dropwise	at	30‐35	°C	and	
after	 the	 addition	was	 completed,	 the	mixture	 was	 stirred	 at	
50‐60	°C	for	3	h,	cooled	to	room	temperature.	The	mixture	was	
poured	 over	 cold	 water	 (2	 cm3),	 acidified	 with	 hydrochloric	
acid	to	give	a	semisolid	product.	The	product	was	refluxed	with	
absolute	 ethanol	 (2	 cm3)	 for	 1	 h,	 cooled,	 filtered,	 and	
recrystallized	 from	 ethanol	 to	 give	 compound	 4	 as	 pale‐gray	
crystals	(Scheme	2).	Yield:	57%.	M.p.:	230‐232	°C.	FT‐IR	(KBr,	ν,	
cm‐1):	 3371	 (OH),	 2975	 (CHaliph),	 2211	 (CN),	 1704	 (s,	
C=Oaldehyde),	1685	(w,	C=Ocoumarin),	1637	(exocyclic	C=C).	1H	NMR	

(500	MHz,	DMSO‐d6,	δ,	ppm):	1.12	(t,	J	=	6.9	Hz,	3H,	CH3),	2.71	
(s,	1H,	‐CH‐),	4.15	(q,	J	=	6.9	Hz,	2H,	CH2),	7.44‐7.48	(m,	2H,	6‐H	
and	8‐H),	 7.73	 (m,	 1H,	 7‐H),	 7.94	 (m,	1H,	5‐H),	8.95,	 9.19	 (ss,	
1H,	 CHO).	 MS	 (EI,	m/z	 (%)):	 256.10	 (M+‐1,	 3.3),	 257.10	 (M+,	
1.7),	 258.10	 (M++1,	 30.9),	 259.10	 (M++2,	 5.0).	 Anal.	 calcd.	 for	
C14H11NO4:	C,	65.37;	H,	4.31;	N,	5.44.	Found:	C,	65.01;	H,	4.11;	N,	
5.12%.	
	
2.2.4.	4‐[(E)‐2‐(Dimethylamino)ethenyl]‐2‐oxo‐2H‐
chromene‐3‐carbonitrile	(5)		
	

A	solution	of	compound	1	(1.0	g,	0.54	mmol)	in	dry	xylene	
(10	cm3),	and	then	DMF‐DMA	(0.7	cm3,	0.58	mmol)	was	added	
and	 the	 mixture	 was	 refluxed	 for	 0.5	 h,	 cooled	 to	 room	
temperature.	 The	 solid	 obtained	 was	 filtered	 off,	 and	
recrystallized	 from	 cyclohexane	 to	 give	 compound	5	 as	 pale‐
green	crystals	(Scheme	2).	Yield:	77%.	M.p.:	209‐210	°C.	FT‐IR	
(KBr,	ν,	cm‐1):	3079,	3001	(CHarom),	2927	(CHaliph),	2197	(CN),	
1682	(C=Ocoumarin),	1616	(C=C).	1H	NMR	(500	MHz,	DMSO‐d6,	δ,	
ppm):	3.12	(s,	3H,	CH3),	3.25	(s,	3H,	CH3),	5.73	(d,	 J	=	12.2	Hz,	
1H,	9‐H),	7.26‐7.30	(m,	2H,	6‐H	and	8‐H),	7.60	(dd,	J	=	12.2	Hz,	
6.8	Hz,	1H,	7‐H),	8.15	(dd,	J	=	7.6	Hz,	4.5	Hz,	1H,	5‐H),	8.47	(d,	J	
=	 12.2	 Hz,	 1H,	 10‐H).	 13C	 NMR	 (125	MHz,	 DMSO‐d6,	 δ,	 ppm):	
39.69,	 40.52,	 78.26,	 88.70,	 117.82,	 118.08,	 120.25,	 124.94,	
126.33,	 133.95,	 152.79,	 155.63,	 160.19.	 MS	 (EI,	 m/z	 (%)):	
240.00	 (M+,	 100.0),	 241.00	 (M++1,	 16.8),	 242.00	 (M++2,	 4.8).	
Anal.	calcd.	for	C14H12N2O2:	C,	69.99;	H,	5.03;	N,	11.66.	Found:	C,	
70.21;	H,	5.23;	N,	11.42%.	



140	 El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	
	

 

	

	
	

Scheme	3
	
	

	
	

Scheme	4
	
	
2.2.5.	3‐Hydroxy‐3,4‐dihydro‐4‐imino‐5H‐chromeno[3,4‐c]	
pyridin‐5‐one	(6)		
	

A	 mixture	 of	 compound	 5	 (0.5	 g,	 0.21	 mmol),	
hydroxylamine	hydrochloride	(0.15	g,	0.21	mmol),	and	ethanol	
(15	cm3)	was	refluxed	for	4	h.	After	cooling	the	solid	obtained	
was	filtered	off,	and	recrystallized	from	DMF	to	give	compound	
6	as	pale‐yellow	crystals	(Scheme	3).	Yield:	85%.	M.p.:	306‐307	
°C.	 FT‐IR	 (KBr,	 ν,	 cm‐1):	 3412	 (OH),	 3241	 (br,	 NH),	 3096	
(CHarom),	1704	(C=Ocoumarin),	1612	(exocyclic	C=N).	1H	NMR	(300	
MHz,	DMSO‐d6,	δ,	ppm):	7.39‐7.64	(m,	4H,	Ar‐H),	8.00	(bs,	1H,	
NH	or	OH	exchangeable	with	D2O),	8.25	(dd,	J	=	8.4	Hz,	1.5	Hz,	
1H,	10‐H),	8.27	(bs,	1H,	NH	or	OH	exchangeable	with	D2O),	8.54	
(d,	J	=	6.9	Hz,	1H,	2‐H).	13C	NMR	(75.46	MHz,	DMSO‐d6,	δ,	ppm):	
69.94,	 71.99,	 104.22,	 116.28,	 117.08,	 120.71,	 124.29,	 125.09,	
131.85,	141.38,	151.23,	218.03.	MS	(EI,	m/z	(%)):	227.20	(M+‐1,	
3.4),	 227.60	 (M+,	 2.8).	 Anal.	 calcd.	 for	 C12H8N2O3:	 C,	 63.16;	 H,	
3.53;	N,	12.28.	Found:	C,	63.33;	H,	3.71;	N,	12.01%.	
	
2.2.6.	3,4‐Dihydro‐4‐imino‐5H‐chromeno[3,4‐c]pyridin‐5‐
one	derivatives	(7‐10)		
	

A	 mixture	 of	 compound	 5	 (0.5	 g,	 0.21	 mmol),	 amine	
derivatives	 (0.21	 mmol)	 in	 glacial	 acetic	 acid	 (5	 cm3)	 was	

refluxed	 for	 4	 h,	 cooled	 to	 room	 temperature.	 The	 solid	
obtained	was	filtered,	and	crystallized	from	the	proper	solvent	
to	give	compounds	7‐10	(Scheme	3).	

4‐Imino‐5‐oxo‐4H‐chromeno[3,4‐c]pyridine‐3(5H)‐
carboxamide	(7):	Obtained	from	urea	(0.13	g),	crystallized	from	
DMF	 as	 pale‐blue	 crystals.	 Yield:	 56%.	 M.p.:	 >	 350	 °C.	 FT‐IR	
(KBr,	 ν,	 cm‐1):	 3440	 (br,	 NH2),	 3173	 (br,	 NH),	 3072	 (CHarom),	
1729	(s,	C=Ocoumarin),	1653	(w,	C=Oamide),	1613	(exocyclic	C=N).	
1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	7.07	(d,	J	=	6.9	Hz,	1H,	7‐
H),	7.32‐7.41	(m,	2H,	1‐H	and	9‐H),	7.68	(dd,	J	=	8.4,	7.5	Hz,	1H,	
8‐H),	7.83	(d,	J	=	6.9	Hz,	1H,	10‐H),	8.16	(d,	J	=	8.1	Hz,	1H,	2‐H),	
12.10	 (bs,	1H,	NH	exchangeable	with	D2O)	 (NH2	protons	were	
displaced	 due	 to	 hydrogen	 bonding	 (Scheme	 4)).	 13C	 NMR	
(75.46	 MHz,	 DMSO‐d6,	 δ,	 ppm):	 80.69,	 98.13,	 107.74,	 115.76,	
116.75,	124.22,	125.56,	133.55,	142.20,	150.29,	153.23,	155.70,	
158.94.	 MS	 (EI,	m/z	 (%)):	 252.00	 (M+‐3,	 5.9),	 253.00	 (M+‐2,	
5.9),	 254	 (M+‐1,	 4.7).	 Anal.	 calcd.	 for	 C13H9N3O3:	 C,	 61.18;	 H,	
3.55;	N,	16.46.	Found:	C,	61.34;	H,	3.11;	N,	16.21%.	

1‐(4‐Imino‐5‐oxo‐4H‐chromeno[3,4‐c]pyridin‐3(5H)‐yl)urea	
(8):	 Obtained	 from	 semicarbazide	 (0.16	 g),	 crystallized	 from	
acetic	 acid	 as	pale‐yellow	crystals.	 Yield:	 71%.	M.p.:	 >	 350	 °C.	
FT‐IR	 (KBr,	 ν,	 cm‐1):	 3447,	 3093	 (br,	 NH,	 NH2),	 1736	
(C=Ocoumarin),	1647	(C=Oamide),	1607	(C=C).		
	



El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	 141	
 

 

	

	
	

Scheme	5
	
	
1H	 NMR	 (500	MHz,	 DMSO‐d6,	 δ,	 ppm):	 7.45‐7.55	 (m,	 2H,	 1‐H	
and	9‐H),	7.66	(d,	J	=	6.9	Hz,	1H,	7‐H),	8.02	(d,	J	=	6.9	Hz,	1H,	8‐
H),	8.42	(d,	J	=	7.6	Hz,	1H,	10‐H),	9.02	(d,	J	=	7.6	Hz,	1H,	2‐H),	
12.46	(bs,	2H,	2NH	exchangeable	with	D2O)	(NH2	protons	were	
displaced	 due	 to	 keto‐enol	 tautomerism	 (Scheme	 4)).	 MS	 (EI,	
m/z	(%)):	269.00	(M+‐1,	16.9),	270.00	(M+,	15.7),	271.00	(M++1,	
15.1).	 	 Anal.	 calcd.	 for	 C13H10N4O3:	 C,	 57.78;	H,	 3.73;	N,	 20.73.	
Found:	C,	57.51;	H,	3.45;	N,	20.45%.	

4‐Imino‐3‐methyl‐3,4‐dihydrochromeno[3,4‐c]pyridin‐5‐one	
(9):	 Obtained	 from	 methylamine	 hydrochloride	 (0.2	 g,	 0.29	
mmol),	 crystallized	 from	 acetic	 acid	 as	 gray	 crystals.	 Yield:	
21%.	M.p.:	 above	 350	 °C.	 FT‐IR	 (KBr,	 ν,	 cm‐1):	 3170	 (br,	 NH),	
3071	 (CHarom),	 1727	 (C=Ocoumarin),	 1614	 (exocyclic	 C=N).	 1H	
NMR	(500	MHz,	DMSO‐d6,	δ,	ppm):	2.50	(s,	3H,	CH3),	7.05	(d,	J	=	
6.9	Hz,	1H,	1‐H),	7.32‐7.37	(m,	2H,	7‐H	and	9‐H),	7.66	(dd,	 J	=	
7.6,	7.6	Hz,	1H,	8‐H),	7.86	(d,	J	=	6.9	Hz,	1H,	2‐H),	8.21	(d,	J	=	8.4	
Hz,	 1H,	 10‐H),	 12.14	 (bs,	 1H,	NH	 exchangeable	with	D2O).	MS	
(EI,	m/z	 (%)):	 225.10	 (M+‐1,	 9.4),	 226.10	 (M+,	 10.7),	 227.10	
(M++1,	 8.9).	 Anal.	 calcd.	 for	 C13H10N2O2:	 C,	 69.02;	 H,	 4.46;	 N,	
12.38.	Found:	C,	68.82;	H,	4.21;	N,	12.01%.	

4‐Imino‐3‐(6‐methyl‐5‐oxo‐3‐thioxo‐2,3‐dihydro‐1,2,4‐
triazin‐4(5H)‐yl)‐3,4‐dihydro‐chromeno[3,4‐c]pyridin‐5‐one	
(10):	 	 Obtained	 from	 4‐amino‐6‐methyl‐3‐thioxo‐3,4‐dihydro‐
1,2,4‐triazin‐5(2H)‐one	(0.33	g),	crystallized	from	acetic	acid	as	
yellow	crystals.	Yield:	54%.	M.p.:	183‐184	°C.	FT‐IR	(KBr,	ν,	cm‐

1):	 3176	 (br,	 NH),	 3064	 (CHarom),	 1727	 (C=Ocoumarin),	 1653	
(C=Otriazine),	1614	(exocyclic	C=N).	1H	NMR	(500	MHz,	DMSO‐d6,	
δ,	ppm):	2.47	(s,	3H,	CH3),	7.06	(d,	J	=	6.1	Hz,	1H,	1‐H),	7.33‐7.37	
(m,	2H,	7‐H	and	9‐H),	7.66	(dd,	1H,	J	=	8.4,	6.8	Hz,	8‐H),	7.86	(d,	
J	=	6.1	Hz,	1H,	2‐H),	8.21	(d,	J	=	7.6	Hz,	1H,	10‐H),	12.19	(s,	1H,	
NH),14.10	 (bs,	 1H,	 NH).	 MS	 (EI,	m/z	 (%)):	 353.10	 (M+,	 0.9),	
354.10	 (M++1,	 1.2),	 355.10	 (M++2,	 0.9).	 Anal.	 calcd.	 for	
C16H11N5O3S:	 C,	 54.38;	 H,	 3.14;	 N,	 19.82;	 S,	 9.07.	 Found:	 C,	
54.10;	H,	2.98;	N,	19.61;	S,	8.81%.	
	

2.2.7.	1H‐Chromeno[3,4‐c]imidazo[1,2‐a]pyridin‐4(2H)‐one	
(11)		
	

A	 mixture	 of	 compound	 5	 (0.5	 g,	 0.21	 mmol),	 2‐
aminoethanol	(0.13	cm3,	0.21	mmol),	and	glacial	acetic	acid	(2	
cm3)	 was	 refluxed	 for	 5	 h,	 cooled	 to	 room	 temperature.	 The	
solid	obtained	was	filtered,	and	crystallized	from	acetic	acid	to	
give	 compound	11	 as	 pale‐yellow	 crystals	 (Scheme	 5).	 Yield:	
61%.	 M.p.:	 180‐182	 °C.	 FT‐IR	 (KBr,	 ν,	 cm‐1):	 3092	 (CHarom),	
2949	 (CHaliph),	 1736	 (C=Ocoumarin),	 1648	 (C=N),	 1609	 (C=C).	 1H	
NMR	 (500	MHz,	 DMSO‐d6,	 δ,	 ppm):	 4.19‐4.29	 (m,	 4H,	 2	 CH2),	
7.11	(d,	 J	=	5.15	Hz,	1H,	6‐H),	7.31‐7.35	(m,	2H,	8‐H	and	9‐H),	
7.63	(d,	 J	=	6.3	Hz,	1H,	10‐H),	8.16‐8.19	(m,	2H,	5‐H	and	7‐H).	
MS	(EI,	m/z	(%)):	238.10	(M+,	6.6),	239.10	(M++1,	2.8),	240.10	
(M++2,	11.5),	241.10	(M++3,	1.9).	Anal.	calcd.	for	C14H10N2O2:	C,	
70.58;	H,	4.23;	N,	11.76.	Found:	C,	70.26;	H,	4.01;	N,	11.44%.	
	
2.2.8.	4,4‐(Ethane‐1,2‐diylbis[imino(z)ethene‐2,1‐diyl])	
bis(2‐oxo‐2H‐chromene‐3‐carbonitrile)	(12)		
	

A	mixture	 of	 compound	5	 (0.5	 g,	 0.21	mmol),	 ethane‐1,2‐
diamine	80%	(0.07	cm3,	0.11	mmol),	and	glacial	acetic	acid	(5	
cm3)	 was	 refluxed	 for	 2	 h,	 cooled	 to	 room	 temperature.	 The	
solid	 obtained	was	 filtered	 off,	 and	 recrystallized	 from	 acetic	
acid	 to	 give	 compound	12	 as	 gray	 crystals	 (Scheme	5).	 Yield:	
21%.	 M.p.:	 183‐185	 °C.	 FT‐IR	 (KBr,	 ν,	 cm‐1):	 3434	 (br,	 OH),	
2225	(CN),	1719	(br,	C=Ocoumarin).	1H	NMR	(500	MHz,	DMSO‐d6,	
δ,	ppm):	2.70‐2.72	(m,	4H,	2	CH2),	6.83‐6.88	(m,	1H,	=CH),	7.11‐
7.14	 (m,	 1H,	 =CH),	 7.44‐7.49	 (m,	 4H,	Ar‐H),	 7.67‐7.78	 (m,	 2H,	
Ar‐H),	 7.92‐7.96	 (m,	 2H,	 Ar‐H),	 8.23	 (d,	 J	 =	 7.6	 Hz,	 1H,	 =CH),	
8.52	(d,	J	=	8.6	Hz,	1H,	=CH),	9.24‐9.45	(m,	1H,	NH	exchangeable	
with	D2O),	10.89	 (bs,	1H,	NH	exchangeable	with	D2O).	MS	 (EI,	
m/z	 (%)):	450.00	 (M+,	14.7),	 451.00	 (M++1,	17.4).	Anal.	 calcd.	
for	C26H18N4O4:	C,	69.33;	H,	4.03;	N,	12.44.	Found:	C,	69.52;	H,	
3.88;	N,	12.11%.	
	



142	 El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	
	

 

	

O O

CN

O O

CN

H

N

H

CH3H3C

O

N

OH

CN

H
N C

S

NH2

N

N

N

O O

NH2

H2NNHCSNH2
AcOH

H2NNHCSNH2
AcOH

5

13a

13b

Reflux 10 minReflux 4 hr

14

Reflux 3 hr / AcOH

59%90%

70%

N
H

H
N C

S

NH2

- H2S

	
	

Scheme	6
	
	
2.2.9.	2‐[2‐(3‐Cyano‐2‐oxo‐2H‐chromen‐4‐yl)ethenyl]	
hydrazinecarbothioamide	(13)		
	

A	 mixture	 of	 compound	 5	 (0.5	 g,	 0.21	 mmol),	
thiosemicarbazide	(0.2	g,	0.21	mmol),	and	glacial	acetic	acid	(5	
cm3)	was	refluxed	for	10	min,	cooled	to	room	temperature.	The	
solid	obtained	was	filtered,	and	crystallized	from	dilute	DMF	to	
give	compound	13	as	yellow	crystals.	Yield:	59%.	M.p.:	173‐174	
°C.	FT‐IR	(KBr,	ν,	cm‐1):	3377,	3257,	3180	(OH,	NH,	NH2),	2238	
(CN),	1726	(C=Ocoumarin).	1H	NMR	(500	MHz,	DMSO‐d6,	δ,	ppm):	
4.01‐4.07	 (m,	 2H,	 NH2	 exchangeable	with	 D2O),	 7.39‐7.47	 (m,	
2H,	Ar‐H	and	=CH),	7.57	(bs,	1H,	Ar‐H),	7.72‐7.75	(m,	1H,	Ar‐H),	
7.92‐7.96	 (m,	 2H,	 Ar‐H	 and	 =CH),	 11.25	 (bs,	 1H,	 NH	
exchangeable	with	D2O)	(NH	proton	was	displaced	due	to	keto‐
enol	 tautomerism	 (Scheme	6)).	MS	 (EI,	m/z	 (%)):	286.00	 (M+,	
80.9),	 287.00	 (M++1,	 65.4).	 Anal.	 calcd.	 for	 C13H10N4O2S:	 C,	
54.54;	H,	 3.52;	N,	 19.57;	 S,	 11.20.	 Found:	 C,	 54.23;	H,	 3.25;	N,	
19.15;	S,	10.91%.	
	
2.2.10.	2‐amino‐4H‐chromeno[3,4‐c][1,2,4]triazolo[1,5‐a]	
pyridin‐4‐one	(14)	
	

Method	 A:	 A	 mixture	 of	 compound	 5	 (0.5	 g,	 0.21	 mmol),	
thiosemicarbazide	(0.2	gm,	0.21	mmol),	and	glacial	acetic	acid	
(5	cm3)	was	refluxed	for	4	h,	cooled	to	room	temperature	and	
poured	 over	water	 (10	 cm3).	 The	 solid	 obtained	was	 filtered,	
and	 crystallized	 from	 ethanol	 to	 give	 compound	14	 as	 purple	
crystals	(Scheme	6).	Yield:	90%.	M.p.:	199‐200	°C.	FT‐IR	(KBr,	ν,	
cm‐1):	3434	(br,	NH2),	1719	(C=Ocoumarin),	1600	(C=N).	1H	NMR	
(500	MHz,	DMSO‐d6,	 δ,	 ppm):	 4.32	 (bs,	 2H,	NH2	 exchangeable	
with	D2O),	7.45‐7.50	(m,	4H,	Ar‐H),	7.79	(dd,	J	=	6.9,	5.3	Hz,	1H,	
Ar‐H),	7.96	(d,	 J	=	7.6	Hz,	1H,	Ar‐H).	MS	(EI,	m/z	 (%)):	252.00	
(M+,	 4.1),	 253.00	 (M++1,	 5.2).	 Anal.	 calcd.	 for	 C13H8N4O2:	 C,	
61.90;	H,	3.20;	N,	22.21.	Found:	C,	61.65;	H,	3.01;	N,	21.91%.	

Method	B:	A	mixture	of	compound	13	 (0.2	g,	0.069	mmol)	
and	 glacial	 acetic	 acid	 (2	mL)	was	 refluxed	 for	 3	 h,	 cooled	 to	

room	 temperature	 and	 poured	 over	 water	 (2	 mL).	 The	 solid	
obtained	 was	 filtered,	 and	 crystallized	 from	 ethanol	 to	 give	
compound	14	as	purple	crystals,	Yield:	70%,	M.p.:	199‐200	°C.	
	
2.2.11.	4‐Imino‐4H,5H‐pyrano[3,4‐c]chromen‐5‐one	(16)	and	
(Z)‐2‐(3‐cyano‐2‐oxo‐2H‐chromen‐4‐yl)vinyl	2‐oxo‐4‐(2‐
oxoethyl)‐2H‐chromene‐3‐carbimidate	(17)		
	

A	mixture	of	compound	5	(0.5	g,	0.21mmol),	acetic	acid	(4	
cm3)	 and	water	 (1	 cm3)	was	 refluxed	 for	 5	h,	 cooled	 to	 room	
temperature	 and	 filtered	 off.	 The	 solid	 obtained	 was	
crystallized	 from	 acetic	 acid	 to	 give	 compound	 17	 as	 pale‐
yellow	crystals	 (Scheme	7).	Yield:	34%,	M.p.:	 340‐342	 °C.	 The	
filtrate	 was	 diluted	 with	 water	 (5	 cm3)	 and	 filtered	 off.	 The	
solid	obtained	was	crystallized	from	ethanol	to	give	compound	
16	as	yellow	crystals	(Scheme	7).	Yield:	22%,	M.p.:	231‐232	°C.	

4‐Imino‐4H,5H‐pyrano[3,4‐c]chromen‐5‐one	 (16):	 FT‐IR	
(KBr,	 ν,	 cm‐1):	 3173	 (br,	 NH),	 3069,	 3031	 (CHarom),	 1732	
(C=Ocoumarin),	1614	(exocyclic	C=N).	 1H	NMR	(500	MHz,	DMSO‐
d6,	δ,	ppm):	7.05	(d,	J	=	6.9	Hz,	1H,	1‐H),	7.32‐7.37	(m,	2H,	7‐H	
and	9‐H),	7.66	(dd,	J	=	7.6,	7.6	Hz,	1H,	8‐H),	7.85	(d,	J	=	6.5	Hz,	
1H,	2‐H),	8.20	 (d,	 J	 =	7.6	Hz,	1H,	10‐H),	12.17	 (s,	1H,	NH).	MS	
(EI,	m/z	(%)):	213.10	(M+,	100.0),	214.10	(M++1,	14.7),	215.10	
(M++2,	 1.6),	 216.10	 (M++3,	 0.1).	 Anal.	 calcd.	 for	 C12H7NO3:	 C,	
67.61;	H,	3.31;	N,	6.57.	Found:	C,	67.50;	H,	3.21;	N,	6.44%.	

(Z)‐2‐(3‐cyano‐2‐oxo‐2H‐chromen‐4‐yl)vinyl	 2‐oxo‐4‐(2‐
oxoethyl)‐2H‐chromene‐3‐carbimidate	 (17):	 FT‐IR	 (KBr,	 ν,	 cm‐

1):	3370	(br,	OH),	3194	(br,	NH),	3075	(CHarom),	2984	(CHaliph),	
2211	(CN),	1727,	1654	(C=Ocoumarin),	1612	(C=N).	1H	NMR	(500	
MHz,	DMSO‐d6,	δ,	ppm):	2.46	(d,	J	=	1.5	Hz,	2H,	CH2),	4.14	(d,	J	=	
6.9	Hz,	1H,	=CH),	7.06	(d,	J	=	6.9	Hz,	1H,	‐O‐CH=),	7.33‐7.37	(m,	
3H,	Ar‐H),	7.46	(dd,	J	=	8.4,	7.6	Hz,	1H,	Ar‐H),	7.65‐7.73	(m,	2H,	
Ar‐H),	7.89	(dd,	J	=	8.4,	6.1	Hz,	1H,	Ar‐H),	8.21	(d,	J	=	8.4	Hz,	1H,	
Ar‐H),	8.94,	9.19	(ss,	1H,	‐CHO),	12.19	(s,	1H,	NH).		
	
	



El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	 143	
 

 

	
Table	1.	Antimicrobial	activities	data	of	compounds	(2‐17).	

Sample	

Gram‐positive	bacteria	 Gram‐negative	bacteria	 Yeasts	b	
Staphylococcus	
aureus	
(ATCC	25923)	

Bacillus	subtilis	
(ATCC	6635)	

Salmonella	
typhimurium	
(ATCC	14028)	

Escherichia	coli	
(ATCC	25922)	

Candida	albicans	
(ATCC	10231)	

Aspergillus	
fumigatus	

Concentration	f	 Concentration	 Concentration Concentration Concentration	 Concentration
1	 0.5	 1	 0.5	 1 0.5 1 0.5 1 0.5	 1	 0.5
Mean	of	zone	diameter	a,	mm	

2	 8	L	d	 7	L	 10	L	 9	I	 ‐	c	 ‐	 8	L	 7	L	 ‐	 ‐	 ‐	 ‐	
3	 ‐	 ‐	 ‐	 ‐	 ‐ ‐ ‐ ‐ ‐ ‐	 ‐	 ‐
4	 ‐	 ‐	 14	I	e	 12	I	 ‐	 ‐	 8	L	 7	L	 11	L	 7	L	 21	I	 16	I	
5	 ‐	 ‐	 12	I	 8	L	 ‐ ‐ ‐ ‐ 9	L 7	L	 ‐	 ‐
6	 ‐	 ‐	 ‐	 ‐	 ‐ ‐ ‐ ‐ ‐ ‐	 10	L	 7	L
7	 ‐	 ‐	 ‐	 ‐	 ‐ ‐ ‐ ‐ ‐ ‐	 10	L	 7	L
8	 ‐	 ‐	 ‐	 ‐	 ‐ ‐ 8	L 7	L ‐ ‐	 ‐	 ‐
9	 ‐	 ‐	 ‐	 ‐	 12	I 7	L 8	L 7	L ‐ ‐	 9	L	 7	L
10	 ‐	 ‐	 ‐	 ‐	 11	L 10	I ‐ ‐ ‐ ‐	 8	L	 7	L
11	 ‐	 ‐	 10	L	 7	L	 11	L	 9	L	 8	L	 7	L	 ‐	 ‐	 8	L	 7	L	
13	 9	L	 7	L	 ‐	 ‐	 ‐ ‐ ‐ ‐ ‐ ‐	 9	L	 7	L
14	 ‐	 ‐	 8	L	 7	L	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	
16	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	
17	 9	L	 7	L	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	
Control	g	 35	 26	 35	 25	 36 28 38 27 35 28	 37	 26
a	Calculate	from	3	values.	
b	Identified	on	the	basis	of	routine	cultural,	morphological	and	microscopical	characteristics. 
c	‐ :	No	effect.	  
d L:	Low	activity	=	Mean	of	zone	diameter	≤	1/3	of	mean	zone	diameter	of	control.	
e I:	Intermediate	activity	=	Mean	of	zone	diameter	≤	2/3	of	mean	zone	diameter	of control.	
f	Concentration,	mg/mL. 
g	Chloramphencol	in	the	case	of	Gram‐positive	bacteria,	Cephalothin in	the	case	of Gram-negative	bacteria	and	cycloheximide	in	the	case	of	fungi.	
	
	
	

	
	

Scheme	7
	
	
MS	 (EI,	 m/z	 (%)):	 426.10	 (M+,	 20.0),	 427.10	 (M++1,	 22.3),	
428.10	 (M++2,	 28.2).	 Anal.	 calcd.	 for	 C24H14N2O6:	 C,	 67.61;	 H,	
3.31;	N,	6.57.	Found:	C,	67.34;	H,	3.09;	N,	6.25%.	
	
2.3.	Antimicrobial	activity	
	

The	newly	 synthesized	 compounds	were	 screened	 against	
Gram‐positive	 bacteria:	 Staphylococcus	 aureus	 (ATCC 25923)	
and	 Bacillus	 subtilis	 (ATCC 6635),	 Gram‐negative	 bacteria:	
Salmonella	 typhimurium	 (ATCC	 14028)	 and	 Escherichia	 coli	
(ATCC	 25922),	 Yeast:	 Candida	 albicans	 (ATCC	 10231)	 and	
Fungus:	 Aspergillus	 fumigatus.	 The	 standardized	 disc‐agar	
diffusion	method	[20]	was	followed	to	determine	the	activity	of	
the	synthesized	compounds	against the	tested	microorganisms.	
The	 tested	compounds	were	dissolved	 in	dimethyl	 formamide	
solvent	and	prepared	in	two	concentrations	1.0	and	0.5	mg/mL.	
Most	of	the	prepared	compounds	showed	a	low	to	intermediate	
antimicrobial	 activity	 towards	 Gram‐positive,	 Gram‐negative	
bacteria	and	fungal	strain	(Table	1).		
	

2.4.	Antitumor	activity	in	planta	
	

An	18‐gauge	needle	 (no	bezel)	was	used	 to	produce	holes	
on	 uniform	 fruits	 of	 summer	 squash	 (Cucurbita	 pepo	 cv.	
Eskandarany)	at	12	sites	distributed	over	3	rows	(4	sites	/	raw)	
per	 fruit.	 Into	 each	 hole,	 2	 µL	 of	 108	 CFU/mL	 Agrobacterium	
tumefaciens	 cell	 suspension	was	pipetted.	After	 the	 liquid	was	
absorbed	by	the	plant	tissue,	the	fruits	were	maintained	for	24	
hr	in	wetted	plastic	containers	with	transparent	plastic	covers.	
After	 24	 hr,	 sites	 were	 re‐wounded	 and	 2	 µL	 from	 the	
concentration	 of	 0.5	 mg/mL	 of	 each	 chemical	 compounds	
suspension	 in	dimethylformamide	was	pipetted	 into	each	site.	
After	 the	 suspension	 was	 absorbed,	 the	 fruits	 were	 again	
backed	to	the	containers	and	kept	wetted	in	growth	chamber	at	
27	±	2	°C	until	galls	measuring	were	assessed.	Number	and	size	
of	 formed	galls	were	 recorded	 after	 10	days.	 Three	 replicates	
were	carried	out	for	each	compound.	
	
	
	



144	 El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	
	

 

	

	
	

Scheme	8
	
	
3.	Results	and	discussion	
	
3.1.	Chemistry	
	

In	our	recent	work,	we	described	the	condensation	of	3,5‐
dichloro‐2‐hydroxyacetophenone	 [2],	 3,5‐dimethyl‐2‐hydroxy	
acetophenone	 [18]	and	unsubstituted	2‐hydroxyacetophenone	
[2]	 with	 ethyl	 cyanoacetate	 in	 the	 presence	 of	 sodium	 metal	
gave	 7‐amino‐2,4‐dichloro(or	 2,4‐dimethyl)‐9‐hydroxy‐6‐oxo‐
6H‐benzo[c]chromene‐8‐carbonitrile,	 and	 a	 mixture	 of	 4‐
methyl‐2‐oxo‐2H‐chromene‐3‐carbonitrile	 and	 7‐amino‐9‐
hydroxy‐6‐oxo‐6H‐benzo[c]chromene‐8‐carbonitrile,	
respectively.	

The	present	work	describes	the	hydrolysis	of	cyano	group	
of	4‐methyl‐2‐oxo‐2H‐chromene‐3‐carbonitrile	(1)	in	ethanolic	
sodium	hydroxide	solution	gave	4‐methyl‐2‐oxo‐2H‐chromene‐
3‐carboxylic	 acid	 (2),	 but	 when	 the	 reaction	 takes	 place	 in	
aqueous	sodium	hydroxide	solution	the	formed	amide	group	in	
one	 molecule	 was	 added	 to	 the	 cyano	 group	 of	 another	
molecule	 afforded	 N‐[imino(4‐methy‐2‐oxo‐2H‐chromen‐3‐
yl)methyl]‐4‐methyl‐2‐oxo‐2H‐chromene‐3‐carboxamide	 (3)	
(Scheme	1).	

On	 the	 other	 hand,	 the	 presence	 of	 carbonyl	 group	 at	
position	2	and	cyano	group	at	position	3	of	2‐oxo‐2H‐chromene	
moiety	facilitate	the	condensation	reactions	of	4‐methyl	group	
of	 compound	 1,	 so	 the	 Vilsmeier	 reaction	 of	 compound	 1	 in	
pyridine	 followed	 by	 reflux	 in	 absolute	 ethanol	 gave	 4‐(1‐
ethoxy‐2‐oxoethyl)‐2‐oxo‐2H‐chromene‐3‐carbonitrile	(4),	and	
condensation	 reaction	 of	 compound	 1	with	 DMF‐DMA	 in	 dry	
xylene	 gave	 4‐[(E)‐2‐(dimethylamino)ethenyl]‐2‐oxo‐2H‐

chromene‐3‐carbonitrile	 (5)	 (Scheme	 2).	 Compound	 5	 which	
was	 found	 to	 exist	 in	 trans	 form,	 as	 revealed	 by	 the	 1H	 NMR	
spectrum	which	 displayed	 olefinic	 protons	 at		 5.73	 and	 8.47	
ppm	with	coupling	constant	12.2	Hz,	typical	for	trans	protons.	

Cyclocondensation	 reactions	of	 compound	5	with	primary	
amines	 afforded	 the	 corresponding	 4‐iminochromeno[3,4‐
c]pyridine	 derivatives.	 So,	 the	 reactions	 of	 compound	 5	 with	
hydroxylamine	 hydrochloride	 in	 ethanol,	 urea,	 semicarbazide,	
methylamine	 hydrochloride	 and	 4‐amino‐6‐methyl‐3‐thioxo‐
3,4‐dihydro‐1,2,4‐triazin‐5(2H)‐one	in	acetic	acid	afforded	3,4‐
dihydro‐4‐ imino‐5H‐chromeno[3 ,4‐c]pyrid in‐5‐one	
derivatives,	6‐10,	respectively	(Scheme	3).	The	protons	of	NH2	
groups	 in	 compounds	 7	 and	 8	 in	 1H	 NMR	 spectra	 were	
displaced	 although	 their	 appearance	 in	 the	 IR	 spectra	 due	 to	
strong	hydrogen	bonding	and	keto‐enol	 tautomerism	(Scheme	
4).		

Also,	 the	cyclocondensation	reactions	of	compound	5	with	
2‐aminoethanol	 and	 with	 ethane‐1,2‐diamine	 in	 acetic	 acid	
produced	 2,3‐dihydro‐imidazo[1,2‐a]‐12H‐chromeno[3,4‐c]	
pyridin‐12‐one	 (11)	 and	 4,4‐ethane‐1,2‐diyl‐bis[imino(z)	
ethene‐2,1‐diyl]}bis(2‐oxo‐2H‐chromene‐3‐carbonitrile)	 (12),	
respectively	(Scheme	5).	

On	the	other	hand,	condensation	and/or	cyclocondensation	
reactions	 of	 compound	 5	 with	 thiosemicarbazide	 in	 the	
presence	 of	 glacial	 acetic	 acid	 depend	 on	 reaction	 conditions.	
When	 the	 reaction	was	 refluxed	 for	 10	min	 afforded	 2‐[2‐(3‐
cyano‐2‐oxo‐2H‐chromen‐4‐yl)ethenyl]hydrazinecarbothio	
amide	(13),	whereas	refluxing	 for	4	hours	gave	2‐amino‐12H‐
chromeno[3,4‐c][1,2,4]triazolo[1,5‐a]pyridin‐12‐one	 (14).	



El‐Shaaer	/	European	Journal	of	Chemistry	4	(2)	(2013)	138‐145	 145	
 

 

Also,	compound	14	was	formed	by	refluxing	of	compound	13	in	
glacial	acetic	acid	for	3	hours	(Scheme	6).	

The	 formation	 of	 cyclocondensation	 products	 6‐10	
proceeded	 via	 the	 nucleophilic	 replacement	 of	 NH2	 group	 of	
amine	derivatives	with	 ‐N(CH3)2	group	of	compound	5	 to	give	
the	 intermediate	 products	 15,	 which	 can	 be	 cyclized	 by	
nucleophilic	 addition	 of	 NH	 group	 to	 CN	 group.	 Also,	 the	
cyclocondensation	 products	 11	 and	 14	 were	 proceeded	 by	
elimination	of	H2O	or	H2S,	respectively	(Scheme	8).	

On	 the	 other	 hand,	 cyclocondensation	 reaction	 of	
compound	5	in	the	presence	of	dilute	acetic	acid	gave	a	mixture	
of	 4‐imino‐4H,5H‐pyrano[3,4‐c]chromen‐5‐one	 (16)	 (22%)	
and	 (Z)‐2‐(3‐cyano‐2‐oxo‐2H‐chromen‐4‐yl)vinyl‐2‐oxo‐4‐(2‐
oxoethyl)‐2H‐chromene‐3‐carbimidate	(17)	(34%)	(Scheme	7).	
Structure	17	was	 assigned	 for	 this	 product	based	on	 1H	NMR	
data,	that	revealed	cis	olefinic	protons	at		4.14	and	7.06	ppm	
with	J	=	6.9	Hz.	
	
3.2.	Antimicrobial	activity	
	

Compounds	 2,	 4	 and	 5	 showed	 intermediate	 activities	
against	 Bacillus	 subtilis,	 while	 compounds	 9	 and	 10	 showed	
intermediate	 activities	 against	 Salmonella	 typhimurium.	 Also,	
compound	4	 showed	 intermediate	 activity	 against	Aspergillus	
fumigatus.	
	
3.3.	Antitumor	activity	in	planta	
	

Chemical	 compounds	 that	 yielded	 the	 greatest	 inhibition	
zones	 in	 vitro	 were	 selected	 to	 demonstrate	 its	 antitumor	
activity	 in	 planta.	 These	 compounds	were	 examined	 for	 their	
capability	 to	 suppress	 gall	 formation	 by	 Agrobacterium	
tumefaciens	 on	 summer	 squash	 fruits.	 The	 strain	 of	
Agrobacterium	 tumefaciens	 used	 as	 tumrigenic	 agent	 in	 this	
study	was	the	isolate	designated	5A.	This	strain	was	originally	
isolated	 from	 rose	 plant	with	 typical	 symptoms	 of	 crown	 gall	
disease.	 The	 obtained	 results	 revealed	 that	 compounds	7	 and	
17	 yielded	 the	 greatest	 inhibition	 zones	 in	 vitro	 against	
Agrobacterium	 tumefaciens	 on	 summer	 squash	 fruits	 (Table	 2	
and	 Figure	 1).	 The	 reason	 for	 the	 higher	 reactivity	 of	
compounds	7	and	17	as	tumrigenic	agents	due	to	the	presence	
of	 chromeno[3,4‐c]pyridine	 carrying	N‐carboxamide	 group	 in	
compound	 7	 and	 two	 isolated	 bioactive	 coumarin	 moiety	 in	
compound	17.		

	
Table	2.	Antitumor	activity	in	planta	data	of	some	synthesized	compounds		
Compound	 Gall	incidence	(%)	 Gall	size	(mm)	*	
2	 100	 2	
3	 100	 4	
5	 100	 3	
7	 0	 ‐	
10	 100	 6	
11	 100	 4	
13	 100	 5	
14	 100	 6	
17	 0	 ‐	
Control	 100	 7	
*	Mean,	nearest	whole,	mm.	
	

																																		Control					Compound	7	Compound	17	
	
Figure	1.	The	inhibition	zones	of	compounds	7	and	17	related	to	control.	

4.	Conclusion	
	

An	 efficient	 synthesis	 of	 some	 new	 isolated	 and	 fused	 2‐
oxo‐2H‐chromene	 derivatives	 starting	 from	 2‐
hydroxyacetophenone	 with	 ethyl	 cyanoacetate	 followed	 by	
cyclocondensation	 reactions	 with	 nitrogen	 nucleophilic	
reagents	is	reported.	The	antitumor	activities	in	planta	 for	the	
prepared	 compounds	 indicated	 that	 compounds	 7	 and	 17	
yielded	 the	 greatest	 inhibition	 zones	 in	 vitro	 against	
Agrobacterium	 tumefaciens	 due	 to	 the	 presence	 of	
chromeno[3,4‐c]pyridine	 carrying	 N‐carboxamide	 group	 and	
two	isolated	bioactive	coumarin	moiety,	respectively.	
	
Acknowledgement	
	

I’m	particularly	gratitude	to	Ibrahim	Hassan	Tolba,	Prof.	of	
Plant	Pathology,	Faculty	of	Agriculture,	Al‐Azhar	University,	for	
his	 kind	 cooperation	 in	 carrying	 out	 the	 antimicrobial	 and	
antitumor	screening	throughout	this	work.	
	
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