untitled


European	Journal	of	Chemistry	3	(2)	(2012)	208‐210	

European	Journal	of	Chemistry	
ISSN	2153‐2249	(Print)	/	ISSN	2153‐2257	(Online)		2012	EURJCHEM	

DOI:10.5155/eurjchem.3.2.208‐210.581	

	
	

	

	

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

	 	 	

An	efficient	and	facile	ring	closure	of	2’‐hydroxychalcones		
under	irradiation	of	tungsten	light	

Sainath	Zangadea,*,	Avinash	Shindeb,	Arvind	Patilb	and	Yeshwant	Vibhuteb	

a	Department	of	Chemistry,	Madhavrao	Patil	Mahavidyalaya,	Palam,	Prabhani,	Maharashtra,	431720,	India	
b	Laboratory	of	Organic	Synthesis,	Department	of	Studies	in	Chemistry,	Yeshwant	Mahavidyalaya,	Nanded,	Maharashtra,	431602,	India	

*Corresponding	author	at:	Department	of	Chemistry,	Madhavrao	Patil	Mahavidyalaya,	Palam,	Prabhani,	Maharashtra,	431720,	India.		
Tel.:	+91.246.2254170;	fax:	+91.246.2253726.	E‐mail	address:	drsbz@rediffmail.com	(S.	Zangade).	

	
	

	 	

	 	 	
ARTICLE	INFORMATION	 	 ABSTRACT
Received:	27	December	2011	
Received	in	revised	form:	01	January	2012	
Accepted:	20	February	2012	
Online:	30	June	2012	

KEYWORDS	

	 An	 efficient,	 green	 and	 facile	 reaction	 has	 been	 reported	 between	 2’‐hydroxychalcones	 and
hydrazine	hydrate	 in	2‐methoxyethanol	 in	presence	of	catalytic	amount	of	acetic	acid	under
irradiation	 of	 tungsten	 light	 to	 afford	 2‐pyrazolines.	 Present	 methodology	 presents	 several
advantages	 including	 simple	 reaction	 procedure,	 no	 need	 of	 catalyst/special	 apparatus	 and
short	reaction	time	giving	quantitative	yields	of	product.	

2‐Pyrazolines	
Tungsten	light	
Photocyclisation	
Green	chemistry	
2‐Methoxyethanol	
2’‐Hydroxychalcones	

	
1.	Introduction	
	

Amongst	 five‐membered	 heterocycles,	 pyrazolines	
represent	 a	 class	 of	 compounds	 of	 great	 importance	 in	
heterocyclic	 chemistry	 [1‐2].	 These	 compounds	 have	 intrinsic	
biological	 activities	 and	 constitute	 the	 structural	 feature	 of	
many	 bioactive	 compounds	 [3‐7].	 Pyrazolines	 also	 exhibit	
excellent	 film‐forming	 properties	 [8].	 A	 classical	 synthesis	 of	
these	compounds	involves	the	condensation	of	α,β‐unsaturated	
carbonyl	 compounds	 with	 hydrazines	 [9].	 Pyrazoline	 also	
synthesized	 by	 using	 microwave	 irradiation	 and	 ultrasound	
irradiation	 [10‐11].	 Recently	 various	 modified	 method	 have	
been	 reported	 for	 the	 synthesis	 of	 2‐pyrazoline	 by	 using	
different	catalyst	such	as	KHSO4H2O/SiO2	[12],	porous	calcium	
hydroxyl	 appatite	 [13],	 mercuric	 acetate	 [14],	 tungsto‐
phosphoric	 acid	 [15],	 Zn	 [16]	 and	 Lewis	 acid/bases	 [17].	 The	
combination	 of	 solvents,	 costly	 chemicals/catalyst	 and	 long	
reaction	 time	 makes	 these	 methods	 environmentally	
hazardous.	 Thus	 utilization	 of	 nontoxic	 chemicals,	 renewable	
materials	and	simple	reaction	conditions	are	 the	key	 issues	of	
green	synthetic	strategy.	 In	view	of	 these	observations	and	 in	
continuation	 of	 earlier	 research	work	 [18‐20],	 it	was	 thought	
worthwhile	to	develop	simple,	facile,	and	efficient	methodology	
for	 the	 synthesis	 of	 2‐pyrazolines	 by	 condensation	 of																		
2’‐hydroxychalcones	 with	 hydrazine	 hydrate	 in	 2‐methoxy‐
ethanol	as	reaction	solvent	under	 irradiation	of	 tungsten	 light	
(Scheme	 1).	 The	 structures	 of	 these	 compounds	 were	
characterized	by	spectroscopic	technique.	
	
2.	Experimental	
	
2.1.	Instrumentation	

Melting	points	were	determined	 in	 an	open	 capillary	 tube	
and	 are	 uncorrected.	 IR	 spectra	were	 recorded	 in	 KBr	 pellets	

on	 a	 Perkin‐Elmer	 FT‐IR	 Shimadzu	 spectrometer.	 1H	 and	 13C	
NMR	 spectra	were	 obtained	 in	 DMSO‐d6	 on	 Avance	 300	MHz	
spectrometer	 using	 TMS	 as	 an	 internal	 standard.	 The	 mass	
spectra	 were	 recorded	 on	 EI‐Shimadzu‐GC‐MS	 spectrometer.	
Elemental	 analyses	 were	 performed	 on	 a	 Carlo	 Erba	 106	
Perkin‐Elmer	model	240	analyzer.		
	
2.2.	Synthesis	

2.2.1.	Synthesis	of	pyrazolines	

In	 50	 mL	 beaker,	 a	 mixture	 of	 2’‐hydroxychalcones	 1a‐g	
(10.0	mmol),	hydrazine	hydrate	(50	mmol)	was	dissolved	in	2‐
methoxyethanol	 (20	 mL)	 by	 warming.	 To	 this	 hot	 reaction	
solution	 0.001	mmol	 of	 acetic	 acid	was	 added	 and	 irradiated	
under	tungsten	light	(100	Watt)	for	25‐32	min,	and	progress	of	
reaction	was	monitored	 on	TLC.	 After	 completion	 of	 reaction,	
the	resultant	mixture	was	poured	with	stirring	 into	water	(20	
mL).	 The	 precipitate	 formed	 was	 filtered	 through	 simple	
büchner	funnel,	washed	with	cold	water	and	crystallized	from	
ethanol	to	yield	2‐pyrazolines	(Scheme	1).	

2‐[5‐(4‐Methoxy‐phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl]‐
naphthalen‐1‐ol	 (2a):	UV/VIS	 (λmax,	nm):	412,	328.	FT‐IR	 (KBr	
cm‐1):	1592	(C=N),	1472,	1542	(C=C),	1232	(C‐N).	1H	NMR	(300	
MHz,	DMSO‐d6,	δ,	ppm):	12.47	 (s,	1H,	OH),	7.83‐7.63	 (m,	10H,	
Ar‐H),6.82	 (s,	 1H,	 NH),	 3.27	 (dd,	 J	 =	 5.0	Hz,	 17.5	Hz,	 1H,	HA),	
3.63	(dd,	J	=	12.1	Hz,	17.5	Hz,	1H,	HB),	4.81	(dd,	J	=	5.0	Hz,	12.0	
Hz,	1H,	HX),	3.78	(s,	3H,	OCH3).	13C	NMR	(75		MHz,	DMSO‐d6,	δ,	
ppm):	160.13	(C	of	Ar‐OCH3),	154.83	(C	of	Ar‐OH),	152.27	(C	of	
C=N),	138.28	(Ar‐C),	137.92	(Ar‐C),	136.28	(Ar‐C),	135.83	(Ar‐
C),	134.72	(Ar‐C),	128.63	(Ar‐C),	128.47	(Ar‐C),	127.79	(Ar‐C),	
127.67	 (Ar‐C),	 126.93	 (Ar‐C),	 126.82	 (Ar‐C),	 124.17	 (Ar‐C),	
122.34	 (Ar‐C),	 117.28	 (Ar‐C),	 56.71	 (C	 of	 OCH3),	 52.13	 (C	 of	
CH),	44.75	(C	of	CH2).	MS	(EI,	m/z	(%)):	318	(M+,	100).		

	



Zangade	et	al.	/	European	Journal	of	Chemistry	3	(2)	(2012)	208‐210	 209	
 

	 	

Ar

O

Ar'

Irradiation under
tungsten light

NH2NH2, 2-Methoxyethanol,
Acetic acid N N

ArAr'

H

1a-g 2a-g

OH

COCH3
OHC

R1

R2

R3R

Ar = Ar' =

	
	
Compound	 R	 R1	 R2	 R3	
2a	 H	 H	 OCH3	 H	
2b	 H	 OCH3	 OCH3	 Br	
2c	 Br	 OCH3	 OCH3 Br
2d	 I	 H	 OCH3	 H	
2e	 H	 H	 F	 H	
2f	 H	 H	 Cl	 H	
2g	 I	 OCH3	 OCH3 Br
	

Scheme	1	
	
	
Anal.	calcd.	for	C20H18O2N2:	C,	75.47;	H,	5.66.	Found:	C,	75.58;	H,	
5.59	%.	

2‐[5‐(3‐Bromo‐4,5‐dimethoxy‐phenyl)‐4,5‐dihydro‐1H‐
pyrazol‐3‐yl]‐naphthalen‐1‐ol	(2b):	UV/VIS	(λmax,	nm):	409,	326.	
FT‐IR	 (KBr	 cm‐1):	 1588	 (C=N),	 1477,	 1538	 (C=C),	 1228	 (C‐N).	
1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	12.55	(s,	1H,	OH),	7.73‐
7.37	(m,	8H,	Ar‐H),	6.88	(s,	1H,	NH),	3.29	(dd,	 J	=	5.1	Hz,	17.5	
Hz,	1H,	HA),	3.68	(dd,	J	=	12.0	Hz,	17.5	Hz,	1H,	HB),	4.84	(dd,	J	=	
5.0	Hz,	12.0	Hz,	1H,	HX),	3.83	(s,	3H,	OCH3),	3.76	(s,	3H,	OCH3).	
13C	 NMR	 (75	 	 MHz,	 DMSO‐d6,	 δ,	 ppm):	 154.67	 (C	 of	 Ar‐OH),	
152.56	(C	of	C=N),152.29	(C	of	Ar‐OCH3),	149.47	(C	of	Ar‐OCH3)	
138.23	 (Ar‐C),	 137.83	 (Ar‐C),	 128.42	 (Ar‐C),	 127.48	 (Ar‐C),	
127.23	 (Ar‐C),	 125.31	 (Ar‐C),	 124.93	 (Ar‐C),	 121.27	 (Ar‐C),	
118.89	 (Ar‐C),	 116.74	 (Ar‐C),	 115.39	 (Ar‐C),	 113.79	 (Ar‐C),	
109.17	(C	of	Ar‐Br),	57.84	(C	of	OCH3),	56.45	(C	of	OCH3),	53.28	
(C	of	 CH),	 43.98	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 427	 (M+,	 100).	
Anal.	calcd.	for	C21H19O3N2Br:	C,	59.01;	H,	4.44.	Found:	C,	59.13;	
H,	4.51	%.	

4‐Bromo‐2‐[5‐(3‐bromo‐4,5‐dimethoxy‐phenyl)‐4,5‐dihydro‐
1H‐pyrazol‐3‐yl]‐naphthalen‐1‐ol	 (2c):	 UV/VIS	 (λmax,	 nm):	 411,	
329.	FT‐IR	(KBr	cm‐1):	1590	(C=N),	1472,	1545	(C=C),	1231	(C‐
N).	 1H	 NMR	 (300	MHz,	 DMSO‐d6,	 δ,	 ppm):	 12.62	 (s,	 1H,	 OH),	
7.89‐7.43	(m,	7H,	Ar‐H),	6.81	(s,	1H,	NH),	3.26	(dd,	 J	=	5.1	Hz,	
17.5	Hz,	1H,	HA),	3.64	(dd,	J	=	12.0	Hz,	17.5	Hz,	1H,	HB),	4.89	(dd,	
J	 =	 5.1	 Hz,	 12.1	 Hz,	 1H,	 HX),	 3.86	 (s,	 3H,	 OCH3),	 3.78	 (s,	 3H,	
OCH3).	 13C	NMR	(75	 	MHz,	DMSO‐d6,	δ,	ppm):	155.31	(C	of	Ar‐
OH),	152.74	(C	of	C=N),	152.39	(C	of	Ar‐OCH3),	149.42	(C	of	Ar‐
OCH3)	139.29	(Ar‐C),	137.13	(Ar‐C),	129.46	(Ar‐C),	128.86	(Ar‐
C),	127.45	(Ar‐C),	126.30	(Ar‐C),	124.97	(Ar‐C),	121.71	(Ar‐C),	
118.28	 (Ar‐C),	 116.71	 (Ar‐C),	 116.39	 (Ar‐C),	 115.39	 (C	 of	Ar‐
Br),	109.22	(C	of	Ar‐Br),	57.92	(C	of	OCH3),	56.42	(C	of	OCH3),	
53.29	 (C	of	 CH),	 43.96	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 506	 (M+,	
100).	Anal.	calcd.	for	C21H18O3N2Br2:C,	49.80;	H,	3.55.	Found:	C,	
49.72;	H,	3.59	%.		

4‐Iodo‐2‐[5‐(4‐methoxy‐phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐
yl]‐naphthalen‐1‐ol	 (2d):	 UV/VIS	 (λmax,	 nm):	 413,	 331.	 FT‐IR	
(KBr	cm‐1):	1592	(C=N),	1476,	1540	(C=C),	1230	(C‐N).	1H	NMR	
(300	MHz,	DMSO‐d6,	 δ,	ppm):	12.58	(s,	1H,	OH),	7.81‐7.34	(m,	
9H,	Ar‐H),	6.84	(s,	1H,	NH),	3.28	(dd,	J	=	5.1	Hz,	17.5	Hz,	1H,	HA),	
3.67	(dd,	J	=	12.1	Hz,	17.5	Hz,	1H,	HB),	4.87	(dd,	J	=	5.1	Hz,	12.1	
Hz,	1H,	HX),	3.74	(s,	3H,	OCH3).	13C	NMR	(75		MHz,	DMSO‐d6,	δ,	
ppm):	159.97	(C	of	Ar‐OCH3),	155.14	(C	of	Ar‐OH),	152.32	(C	of	
C=N),	137.83	(Ar‐C),	137.97	(Ar‐C),	136.45	(Ar‐C),	136.83	(Ar‐

C),	135.62	(Ar‐C),	129.36	(Ar‐C),	128.41	(Ar‐C),	128.79	(Ar‐C),	
127.17	 (Ar‐C),	 126.90	 (Ar‐C),	 126.79	 (Ar‐C),	 124.28	 (Ar‐C),	
123.64	(Ar‐C),	108.12	(C	of	Ar‐I),	56.73	(C	of	OCH3),	52.17	(C	of	
CH),	 44.63	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 444	 (M+,	 100).	 Anal.	
calcd.	for	C20H17O2N2I:	C,	54.05;	H,	3.82.	Found:	C,	54.17;	H,	3.78	
%.	

2‐[5‐(4‐Fluoro‐phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl]‐4‐iodo‐
naphthalen‐1‐ol	 (2e):	UV/VIS	 (λmax,	nm):	410,	330.	FT‐IR	 (KBr	
cm‐1):	1588	(C=N),	1468,	1542	(C=C),	1228	(C‐N).	1H	NMR	(300	
MHz,	DMSO‐d6,	δ,	ppm):	12.48	(s,	1H,	OH),	7.88‐7.37	(m,	9H,	Ar‐
H),	6.87	(s,	1H,	NH),	3.30	(dd,	J	=	5.2	Hz,	17.6	Hz,	1H,	HA),	3.70	
(dd,	J	=	12.1	Hz,	17.6	Hz,	1H,	HB),	4.89	(dd,	J	=	5.2	Hz,	12.1	Hz,	
1H,	HX).	13C	NMR	(75		MHz,	DMSO‐d6,	δ,	ppm):	155.23	(C	of	Ar‐
OH),	 152.48	 (C	of	 C=N),	 137.18	 (Ar‐C),	 137.82	 (Ar‐C),	 136.25	
(Ar‐C),	136.96	(Ar‐C),	135.27	(Ar‐C),	129.31	(Ar‐C),	129.57	(Ar‐
C),	128.62	(Ar‐C),	127.19	(Ar‐C),	127.91	(Ar‐C),	126.73	(Ar‐C),	
125.57	 (Ar‐C),	 124.88	 (Ar‐C),122.65	 (Ar‐C),	 109.98	 (C	ofAr‐I),	
52.26	 (C	of	 CH),	 44.60	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 432	 (M+,	
100).	Anal.	 calcd.	 for	C19H14N2OIF:	C,	52.77;	H,	3.24.	Found:	C,	
52.84;	H,	3.27	%.	

2‐[5‐(4‐Chloro‐phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl]‐4‐iodo‐
naphthalen‐1‐ol	 (2f):	 UV/VIS	 (λmax,	 nm):	 409,	 328.	 FT‐IR	 (KBr	
cm‐1):	1590	(C=N),	1475,	1552	(C=C),	1232	(C‐N).	1H	NMR	(300	
MHz,	DMSO‐d6,	δ,	ppm):	12.56	(s,	1H,	OH),	7.92‐7.39	(m,	9H,	Ar‐
H),	6.90	(s,	1H,	NH),	3.28	(dd,	J	=	5.1	Hz,	17.6	Hz,	1H,	HA),	3.69	
(dd,	J	=	12.1	Hz,	17.6	Hz,	1H,	HB),	4.87	(dd,	J	=	5.1	Hz,	12.1	Hz,	
1H,	HX).	13C	NMR	(75		MHz,	DMSO‐d6,	δ,	ppm):	156.14	(C	of	Ar‐
OH),	 152.67	 (C	of	 C=N),	 138.41	 (Ar‐C),	 138.63	 (Ar‐C),	 136.87	
(Ar‐C),	135.19	(Ar‐C),	135.54	(Ar‐C),	133.27	(Ar‐C),	131.39	(Ar‐
C),	128.50	(Ar‐C),	127.47	(Ar‐C),	127.98	(Ar‐C),	126.25	(Ar‐C),	
125.52	(Ar‐C),	124.90	(Ar‐C),	122.69	(Ar‐C)	109.83	(C	of	Ar‐I),	
53.16	 (C	of	 CH),	 44.65	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 448	 (M+,	
100).	Anal.	calcd.	 for	C19H14N2OICl:	C,	50.89;	H,	3.12.	Found:	C,	
50.82;	H,	3.15	%.	

2‐[5‐(3‐Bromo‐4,5‐dimethoxy‐phenyl)‐4,5‐dihydro‐1H‐
pyrazol‐3‐yl]‐4‐iodo‐naphthalen‐1‐ol	 (2g):	 UV/VIS	 (λmax,	 nm):	
410,	 330.	 FT‐IR	 (KBr	 cm‐1):	 1592	 (C=N),	 1470,	 1560	 (C=C),	
1234	(C‐N).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	12.48	(s,	1H,	
OH),	7.78‐7.34	(m,	7H,	Ar‐H),	6.92	(s,	1H,	NH),	3.32	(dd,	J	=	5.2	
Hz,	17.5	Hz,	1H,	HA),	3.70	(dd,	J	=	12.1	Hz,	17.5	Hz,	1H,	HB),	4.88	
(dd,	J	=	5.2	Hz,	12.1	Hz,	1H,	HX),	3.88	(s,	3H,	OCH3),	3.73	(s,	3H,	
OCH3).	 13C	NMR	(75	 	MHz,	DMSO‐d6,	δ,	ppm):	154.88	(C	of	Ar‐
OH),	152.48	(C	of	C=N),	151.89	(C	of	Ar‐OCH3),	149.50	(C	of	Ar‐



210	 Zangade	et	al.	/	European	Journal	of	Chemistry	3	(2)	(2012)	208‐210	
	
OCH3)	138.37	(Ar‐C),	138.86	(Ar‐C),	128.25	(Ar‐C),	127.92	(Ar‐
C),	126.13	(Ar‐C),	125.75	(Ar‐C),	124.40	(Ar‐C),	121.27	(Ar‐C),	
118.59	 (Ar‐C),	 114.94	 (Ar‐C),	 115.80	 (Ar‐C),	 113.19	 (Ar‐C),	
109.22	(C	of	Ar‐Br),	57.66	(C	of	OCH3),	56.40	(C	of	OCH3),	53.29	
(C	of	 CH),	 43.85	 (C	of	 CH2).	MS	 (EI,	m/z	 (%)):	 553	 (M+,	 100).	
Anal.	 cacld.	 for	 C21H18O3N2IBr:	 C,	 45.56;	 H,	 3.25.	 Found:	 C,	
45.64;	H,	3.18	%.	
	
3.	Result	and	discussion		
	

In	 present	 communication,	 we	 have	 described	 the	
photocyclisation	of	2’‐hydroxychalcones	by	the	reaction	of	1a‐g	
with	 hydrazine	 hydrate	 in	 presence	 of	 catalytic	 amount	 of	
acetic	 acid	 using	 tungsten	 light	 irradiation	 to	 obtained	 2‐
pyrazolines	2a‐g.	A	variety	of	methods	have	been	reported	for	
the	preparation	of	this	class	of	compounds.	However	in	spite	of	
their	 potential	 utility,	 some	 of	 the	 reported	 methods	 suffer	
from	 drawbacks	 such	 as	 long	 reaction	 time,	 cumbersome	
product	 isolation	procedure	and	environmental	 concerns.	The	
use	of	tungsten	light	can	be	considered	as	ideal	green	route	for	
synthesis	 of	2‐pyrazolines	 since	 they	are	not	 expensive,	 could	
be	successfully	used	in	place	of	toxic	or	expensive	chemicals	to	
over	come	the	activation	energy	in	organic	synthesis.	

Initially	 we	 attempted	 the	 condensation	 of	 4‐bromo‐2‐[5‐
(3‐bromo‐4,5‐dimethoxy‐phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐
yl]‐naphthalen‐1‐ol	 (1c)	 with	 hydrazine	 hydrate	 using	 acetic	
acid	 in	 2‐methoxyethanol	 in	 combination	 with	 tungsten	 light	
irradiation.	 The	 reaction	went	 completion	within	 25	min	 and	
corresponding	product	2c	obtained	 in	92%	yield	 (Table	1).	 In	
view	 of	 these	 results	 we	 focus	 our	 attention	 towards	 variety	
substituted	2‐hydroxychalcones.	In	all	cases	reaction	proceeds	
efficiently	 giving	 excellent	 yields	 of	 product.	 Structures	 of	
compounds	 2a‐g	 have	 been	 elucidated	 by	 UV,	 IR,	 1H	 NMR	
and13C	NMR	measurements.	Their	 IR	spectra	show	absence	of	
carbonyl	absorption	band	and	the	appearance	of	characteristic	
absorption	band	for	νC=N	at	1592‐1588	cm‐1.	In	1H	NMR	spectra	
show	an	ABX	spin	system	was	observable,	HA,	HB	and	HX	appear	
as	pair	 of	 doublets	near	 δ	3.29,	3.66	 and	4.85	ppm	with	 JAB	 =	
17.5	HZ,	JAX	=	5.1	HZ,	JBX	=	12.1	HZ	and	singlet	of	2‐H	pyrazolines	
around	 at	 δ	 6.87	 ppm,	 respectively.	 In	 13C	 NMR	 spectra,	 the	
chemical	 shifts	value	of	carbon	atoms	C‐3	 (152	ppm),	C‐4	 (44	
ppm),	and	C‐5	(53‐52	ppm).	
	
Table	1.	Synthesis	of	2‐pyrazolines	under	irradiation	of	tungsten	light	(100	
watt).	
Product	 Time	(min)	 Melting	point	(oC)	 Yield	(%)	
2a	 32	 148‐150	 82
2b	 28	 160‐163	 86
2c	 25	 177‐179	 92
2d	 30	 153‐155	 84	
2e	 28	 128‐130	 88		
2f	 30	 136‐137	 85	
2g	 26	 186‐188	 90	
	
4.	Conclusion	
	

We	 have	 developed	 a	 simple	 practical	 procedure	 for	
synthesis	 of	 2‐pyrazolines	 from	 2’‐hydroxychalcones	 using	
tungsten	light.	The	process	is	simple,	efficient,	and	economical.	
It	is	also	consistent	with	the	green	chemistry	approach	because	
it	does	not	need	heating.	
	
Acknowledgements	
	

The	 authors	 gratefully	 acknowledge	 University	 Grant	
Commission	 New	 Delhi	 for	 sanctioning	 major	 research	 grant	
(No.	38‐267/2009).	The	authors	are	also	thankful	to	Principal,	
Yeshwant	 Mahavidyalaya,	 Nanded,	 for	 providing	 laboratory	
facilities	and	Director	 Indian	 Institute	of	Chemical	Technology	
(IICT),	 Hyderabad,	 for	 providing	 necessary	 instrumental	
facilities.		
	
	

References	
	
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