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European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	

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

DOI:10.5155/eurjchem.3.4.485‐492.655	

	
	

	

	

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

	 	 	

Regiospecific	synthesis	of	some	novel	N‐nucleosides	of	4‐amino‐5‐substituted‐
1,2,4‐triazole‐3‐thiones	and	their	in‐vitro	antimicrobial	activity	

Humaira	Nadeem	a	and	Zaman	Ashraf		b,*	

a	Riphah	Institute	of	Pharmaceutical	Sciences,	Riphah	International	University,	Islamabad,	44000,	Pakistan	
b	Department	of	Chemistry,	Allama	Iqbal	Open	University,	Islamabad,	44000,	Pakistan	

*Corresponding	author	at:	Department	of	Chemistry,	Allama	Iqbal	Open	University,	Islamabad,	44000,	Pakistan.		
Tel.:	+92.321.5194461;	Fax:	+92.51.2891471.	E‐mail	address:	mzchem@yahoo.com	(Z.	Ashraf).	

	
	

	 	

	 	 	
ARTICLE	INFORMATION	 	 ABSTRACT
Received:	20	June	2012	
Received	in	revised	form:	26	September	2012	
Accepted:	05	November	2012	
Online:	31	December	2012	

KEYWORDS	

	 4‐Amino‐5‐substituted‐1,2,4‐triazole‐3‐thiones	 were	 prepared	 by	 following	 two	 different
reaction	 routes	 and	 comparing	 the	 effectiveness	 of	 using	 different	 reaction	 conditions.	 The
coupling	 of	 aminotriazoles	 with	 acetylated	 α‐bromo‐D‐glucose	 furnished	 protected	 N‐
nucleosides	regiospecifically.	The	reagents	used	gave	only	one	regioisomer	N‐glycosides	not
the	 other	 S‐nucleosides.	 The	 protected	 nucleosides	 upon	 deacetylation	 using	 methanolic
ammonia	afforded	deprotected	products.	The	chemical	structures	of	synthesized	compounds
were	confirmed	by	FT‐IR,	1H	NMR,	13C	NMR,	mass	spectroscopic	and	elemental	analysis	data.
All	of	 the	synthesized	 compounds	were	 tested	against	 ten	different	 gram	positive	and	gram
negative	 bacterial	 strains	 which	 exhibited	 moderate	 to	 good	 antibacterial	 activity.	 The
deprotected	 nucleosides	 portrayed	 high	 antibacterial	 activity	 than	 4‐amino‐5‐substituted‐
1,2,4‐triazole‐3‐thiones	and	protected	nucleosides	against	selected	bacteria.	

Spectroscopy	
N‐nucleosides	
Regiospecificity	
Antimicrobial	activity	
1,2,4‐Triazole‐3‐thiones	
5‐Aryl/hetero	aryl	substitution	

	
1.	Introduction	
	

Several	 five	 membered	 aromatic	 systems	 having	 three	
hetero	 atoms	 at	 symmetrical	 position	 have	 been	 studied	
because	 of	 their	 interesting	 physiological	 properties	 [1,2].	 In	
the	 last	few	decades,	 the	chemistry	of	1,2,4‐triazoles	and	their	
fused	 heterocyclic	 derivatives	 has	 received	 considerable	
attention	 owing	 to	 their	 synthetic	 and	 effective	 biological	
importance.	 For	 example,	 a	 large	 number	 of	 1,2,4‐triazole‐
containing	 ring	 system	 have	 been	 incorporated	 into	 a	 wide	
variety	of	therapeutically	interesting	drug	candidates	including	
anti‐inflammatory,	 central	 nervous	 system	 (CNS)	 stimulants,	
sedatives,	anxyolytic,	antimicrobial	agents	[3,4].	Derivatives	of	
1,2,4‐triazole	and	1,3,4‐thiadiazole	condensed	nucleus	systems	
(triazolothiadiazoles)	 found	 to	 have	 diverse	 pharmacological	
activities	 including	unique	anti‐inflammatory,	anti‐edema,	and	
analgesic	 properties	 [5‐9].	 Also,	 there	 are	 known	 drugs	
containing	 the	1,2,4‐triazole	group	e.g.	Triazolam,	Alprazolam,	
Etizolam,	and	Furacylin	[10].		

Several	triazolothiadiazole	derivatives	have	been	prepared	
from	 different	 non‐steroidal	 anti‐inflammatory	 agents	 and	
found	to	possess	improved	pharmacological	profile	[11‐13].	In	
addition	 to	 these	 important	 biological	 applications,	mercapto‐
1,2,4‐triazoles	 are	 also	 of	 great	 utility	 in	 preparative	 organic	
chemistry,	 for	 example,	 in	 the	 presence	 of	 various	 reagents,	
undergo	different	types	of	reactions	to	yield	other	heterocyclic	
compounds,	 e.g.	 thiazolotriazoles,	 triazolothiadiazoles,	
triazolothiazines,	triazolothiazepines	and	triazolothiadiazines.	

The	 reaction	 of	 carboxylic	 acid	 chlorides	 and	
thiosemicarbazide	 gave	 acylthiosemicarcarbazide	 which	
without	purification	were	cyclized	in	alkaline	media	to	yield	the	
corresponding	2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thiones	[14‐15].	
Moreover,	 the	 1,2,4‐triazole‐5‐thiones	 were	 prepared	 by	
cyclization	 of	 the	 corresponding	 thiosemicarbazide	 [16].												

5‐Furan‐2‐yl‐4H‐1,2,4‐triazole‐3‐thiol	 was	 prepared	 by	 the	
reaction	 of	 the	 appropriate	 2‐furoyl‐thiosemicarbazide	 and	
potassium	 hydroxide	 in	 ethanol	 for	 3	 hours	 under	 reflux,	
followed	by	acidification	with	acetic	acid	[17,18].	

In	 view	 of	 the	 above	mentioned	 extensive	 applications	 of	
1,2,4‐triazoles	 and	 their	 nucleosides,	 we	 describe	 herein	 the	
synthesis	 of	 some	 novel	 5‐substituted‐4‐amino‐1,2,4‐triazole‐
3‐thiones	 and	 their	 nucleosides	 and	 evaluation	 of	 their	
antimicrobial	 activities.	 The	 reaction	 sequence	 leading	 to	 the	
formation	 of	 desired	 heterocyclic	 compounds	 are	 outlined	 in	
Scheme	1.	The	structures	of	 the	compounds	were	assigned	on	
the	basis	of	FT‐IR,	1H	NMR,	13C	NMR	and	mass	spectral	data.		
	
2.	Experimental	
	

Melting	 points	 were	 recorded	 using	 a	 digital	 Gallenkamp	
(SANYO)	model	MPD.BM	3.5	apparatus	and	are	uncorrected.	1H	
and	13C	NMR	spectra	were	determined	in	DMSO‐d6	at	300	MHz	
and	75	MHz,	 respectively,	using	a	Bruker	 spectrometer.	FT‐IR	
spectra	 were	 recorded	 on	 Perkin	 Elmer	 Spectrum	 BX	
spectrophotometer	as	KBr	pellets.	Mass	Spectra	(EI,	70	eV)	on	a	
MAT	312	 instrument,	 and	elemental	analyses	were	conducted	
using	 a	 LECO‐183	 CHNS	 analyzer.	 Antimicrobial	 activity	 was	
carried	out	at	The	Riphah	Institute	of	Pharmaceutical	Sciences,	
Riphah	 International	 University	 Islamabad,	 Pakistan.	 All	
chemicals	were	purchased	 from	Merck	 and	Aldrich,	 and	were	
used	without	further	purification.	
	
2.1.	Synthesis	of	5‐substituted‐4‐amino‐1,2,4‐triazole‐3‐
thiones	(2a‐j)	
	

Method	 A:	A	 solution	 of	 KOH	 (0.022	moles)	 in	 water	 (20	
mL)	 was	 added	 dropwise	 to	 a	 solution	 of	 hydrazide	 (0.022	
moles)	and	carbondisulfide	(0.028	moles)	in	ethanol	(100‐150	
mL).		



486	 Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	
	

	

	
	

Scheme	1
	
	
The	 reaction	 mixture	 was	 refluxed	 until	 the	 evolution	 of	

hydrogen	 sulfide	 ceases.	 After	 completion	 of	 reaction	 it	 was	
concentrated.	The	 residue	was	divided	 into	 two	portions.	One	
portion	was	 treated	with	 diethyl	 ether	 to	 give	 the	 potassium	
salt	 of	 corresponding	 oxadiazole,	 which	 was	 filtered.	 To	 the	
solution	of	potassium	salt	in	water	(4	mL)	was	added	hydrazine	
hydrate	(80%)	under	reflux.	The	reaction	time	was	monitored	
through	 TLC	 (silica;	 ethylacetate:petroleum,	 ether	 3:1).	 After	
completion	of	 reaction,	 the	 reaction	mixture	was	diluted	with	
water	 and	 acidified	with	 4	N	 hydrochloric	 acid.	 The	 resulting	
solid	was	 filtered,	washed	with	water	 and	 recrystallized	 from	
ethanol	(Scheme	1).	

Method	B:	The	residue	from	Method	A	was	diluted	with	200	
mL	of	distilled	water	and	acidified	with	4	N	HCl	to	pH	=	2‐3.	The	
solid	 separated	 was	 filtered	 and	 recrystallized	 from	 ethanol.	
The	 resulting	 oxadiazole	 (0.01	moles)	 and	 hydrazine	 hydrate	
(99%,	0.03	moles)	 in	 absolute	 ethanol	 (20	mL)	were	 refluxed	
for	6‐8	hours	until	the	reaction	was	completed.	The	solvent	and	
excess	 hydrazine	 hydrate	 were	 removed	 under	 reduced	
pressure.	 The	 residue	 was	 washed	 with	 ether	 and	
recrystallized	 from	ethanol	 to	afford	the	desired	pure	product	
(Scheme	1).	

4‐Amino‐5‐(2‐pyridyl)‐1,2,4‐triazole‐3‐thione	 (2a):	 Yield:	
65%	 (Method	 A).	 M.p.:	 210	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3430‐3330	
(NH2),	 1630	 (Ar	 C=C),	 1567	 (C=N),	 1238	 (C=S).	 1H	NMR	 (300	
MHz,	DMSO‐d6,	δ,	ppm):	8.03	(d,	1H,	 J	=	7.9	Hz,	H‐3’’),	8.60	(d,	
1H,	J	=	5.0	Hz,	H‐6’’),	7.81	(t,	1H,	J	=	6.7	Hz,	H‐4’’),	7.37	(t,	1H,	J	=	
5.3	 Hz,	 H‐5’’),	 5.54	 (s,	 2H,	 NH2),	 13.8	 (s,	 1H,	 NH/SH).	 EI‐MS	
(m/z,	 (%)):	 193	 (M+,	 100),	 162	 (6.2),	 122	 (10.3),	 119	 (33.2),	
111	(3.0),	105	(20.3),	92	(10.1),	91	(4.0),	85	(15.9),	83	(25.3),	
78	(36.6),	60	(34.6).	UV	(λ	max,	EtOH):	324.61,	285.45.	

4‐Amino‐5‐(3‐pyridyl)‐1,2,4‐triazole‐3‐thione	 (2b):	 Yield:	
57%	 (Method	 B).	 M.p.:	 218	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3436‐3334	
(NH2),	 1627	 (Ar	 C=C),	 1570	 (C=N),	 1247(C=S).	 1H	 NMR	 (300	
MHz,	DMSO‐d6,	δ,	ppm):	9.13	(d,	1H,	 J	=	1.5	Hz,	H‐2’’),	8.68	(d,	
1H,	J	=	3.5	Hz,	H‐6’’),	8.36	(d,	1H,	J	=	7.9	Hz,	H‐4’’),	7.56	(dd,	1H,			

J	 =	 7.9	 Hz,	 J	 =	 4.9	 Hz,	 H‐5’’),	 5.79	 (s,	 2H,	 NH2),	 12.6	 (s,	 1H,	
NH/SH).	 EI‐MS	 (m/z,	 (%)):	 193	 (M+,	 100),	 162	 (4.46),	 135	
(8.74),	 122	 (12.80),	 118	 (8.96),	 105	 (19.37),	 91	 (5.39),	 85	
(13.15),	83	(20.2),	78	(23.4),	60	(34.9).	UV	(λ	max,	EtOH):	326.91,	
282.45.	

	5‐(4‐Pyridyl)‐4‐amino‐1,2,4‐triazole‐3‐thione	 (2c):	 Yield:	
70%	 (Method	 A).	M.p.:	 226	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3272	 (NH2),	
1629	 (Ar	 C=C),	 1566	 (C=N),	 1218	 (C=S).	 1H	 NMR	 (300	 MHz,	
DMSO‐d6,	δ,	ppm):	8.82	(d,	2H,	J	=	5.9	Hz,	H‐3’’,	H‐5’’),	7.83	(d,	
2H,	 J	 =	 6.0	 Hz,	 H‐2’’,	 H‐6’’),	 5.53	 (s,	 2H,	 NH2),	 13.7	 (s,	 1H,	
NH/SH).	EI‐MS	(m/z,	(%)):	193	(M+,	100),	162	(7.2),	122	(6.3),	
119	(57.0),	111	(3.0),	105	(27.3),	91	(2.0),	85	(46.9),	83	(5.3),	
78	(36.6),	60	(6.7),	56	(18.6).	UV	(λ	max,	EtOH):	328.24,	275.48.	

4‐Amino‐5‐(4‐methylphenyl)‐1,2,4‐triazole‐3‐thione	 (2d):	
Yield:	 68%	 (Method	B).	M.p.:	 208	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3427‐
3309	 (NH2),	1630	 (Ar	C=C),	1588	 (C=N),	1236	 (C=S).	 1H	NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	7.23‐7.39	(m,	4H,	Ar‐H),	5.49	(s,	
2H,	NH2),	 2.71	 (s,	 3H,	 CH3),	 12.8	 (s,	 1H,	 NH/SH).	 EI‐MS	 (m/z,	
(%)):	 206	 (M+,	 100),	 191	 (1.94),	 175	 (2.94),	 160	 (1.83),	 135	
(47.33),	 132	 (7.79),	 118	 (46.92),	 117	 (29.92),	 102	 (7.31),	 91	
(26.47),	78	 (2.66),	77	 (4.89),	65	 (14.47),	60	 (29.14).	UV	 (λmax,	
EtOH):	327.32,	280.42.	

4‐Amino‐5‐(3,4,5‐trimethoxyphenyl)‐1,2,4‐triazole‐3‐thione	
(2e):	 Yield:	 60%	 (Method	 B).	 M.p.:	 220	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	
3438‐3325	(NH2),	1630	(Ar	C=C),	1578	(C=N),	1268	(C=S).	 1H	
NMR	 (300	MHz,	DMSO‐d6,	 δ,	 ppm):	 δ	7.33	 (s,	 2H,	H‐2’’,	H‐6’’),	
3.71	(s,	9H,	‐OCH3),	5.81	(s,	2H,	NH2),	13.2	(s,	1H,	NH/SH).	EI‐
MS	 (m/z,	 (%)):	 296	 (M+,	 100),	 281	 (36.70),	 235	 (5.31),	 249	
(1.72),	218	 (2.16),	193	 (21.49),	178	 (19.34),	150	 (10.23),	135	
(10.35),	 120	 (11.69),	 118	 (6.57),	 105	 (1.51),	 103	 (15.50),	 93	
(2.80),	90	(3.23),	77	(3.39),	74	(8.62),	64	(8.43),	60	(75.88).	UV	
(λ	max,	EtOH):	325.46,	280.75.	

4‐Amino‐5‐(4‐fluorophenyl)‐1,2,4‐triazole‐3‐thione	 (2f):	
Yield:	 58%	 (Method	A).	M.p.:	 205	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3456‐
3310	 (NH2),	1637	 (Ar	C=C),	1585	 (C=N),	1238	 (C=S).	 1H	NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	7.93	(m,	2H,	H	‐2’’,	H‐6’’),	7.20	(m,	



Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	 487	
 

2H,	H‐3’’,	H‐5’’),	 5.75	 (s,	 2H,	NH2),	 12.5	 (s,	1H,	NH/SH).	EI‐MS	
(m/z,	(%)):	210	(M+,	100),	209	(1.1),	194	(2.8),	180	(4.1),	178	
(2.7),	138	(33.4),	121	(39.51),	108	(10.2),	102	(20.3),	89	(7.8),	
75	(32.1),	60	(56.4).	UV	(λ	max,	EtOH):	320.26,	276.35.	

4‐Amino‐5‐(4‐chlorophenyl)‐1,2,4‐triazole‐3‐thione	 (2g):	
Yield:	 78%	 (Method	 A).	M.p.:	 208	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3410‐
3310	 (NH2),	1636	 (Ar	C=C),	1595	 (C=N),	1233	 (C=S).	 1H	NMR	
(300	MHz,	DMSO‐d6,	δ,	ppm):	8.05	(d,	2H,	 J	=	8.1	Hz,	H	‐2’’,	H‐
6’’),	7.59	(d,	2H,	J	=	8.1	Hz,	H‐3’’,	H‐5’’),	5.77	(bs,	2H,	NH2),	13.9	
(bs,	 1H,	NH/SH).	 EI‐MS	 (m/z,	 (%)):	 226	 (M+,100),	 211	 (1.16),	
195	(3.70),	157	(14.56),	155	(40.92),	138	(38.91),	137	(35.47),	
127	 (2.17),	125	(7.04),	113	 (11.14),	111	 (22.80),	102	 (26.85),	
95	(3.68),	89	(9.52),	76	 (11.01),	75	(29.27),	60	(54.81).	UV	 (λ	
max,	EtOH):	327.43,	281.95.	

4‐Amino‐5‐(4‐Bromophenyl)‐1,2,4‐triazole‐3‐thione	 (2h):	
Yield:	 80%	 (Method	 B).	M.p.:	 202	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3455‐
3318	 (NH2),	1613	 (Ar	C=C),	1594	 (C=N),	1235	 (C=S).	 1H	NMR	
(300	MHz,	DMSO‐d6,	 δ,	ppm):	8.05	 (d,	2H,	 J	=	8.3	Hz,	H‐2’’,	H‐
6’’),	7.63	(d,	2H,	J	=	8.4	Hz,	H‐3’’,	H‐5’’),	5.25	(s,	2H,	NH2),	13.6	
(bs,	 1H,	 NH/SH).	 EI‐MS	 (m/z,	 (%)):	 271	 (M+,	 38),	 270	 (M+‐1,	
100),	255	(2.6),	241	(1.2),	239	(4.5),	199	(42.7),	182	(15.3),	142	
(16.8),	155	(2.8),	102	(31.7),	75	(67.8).	UV	(λ	max,	EtOH):	326.45,	
288.15,	245.41.	

4‐Amino‐5‐(2‐naphthyl)‐1,2,4‐triazole‐3‐thione	 (2i):	 Yield:	
81%	(Method	B).	M.p.:	205‐206	oC.	IR	(KBr,	ν,	cm‐1):	3420‐3305	
(NH2),	 1625	 (Ar	 C=C),	 1526	 (C=N),	 1232	 (C=S).	 1H	NMR	 (300	
MHz,	DMSO‐d6,	δ,	ppm):	8.80	(s,	1H,	H‐1’’),	8.10	(dd,	1H,	 J=7.5	
Hz,	 4.6	Hz,	Naphthyl‐H),	 7.86‐7.98	 (m,	 3H,	Naphthyl‐H),	 7.54‐
7.62	 (m,	 2H,	 Naphthyl‐H),	 5.15	 (s,	 2H,	 NH2),	 13.5	 (bs,	 1H,	
NH/SH).	EI‐MS	(m/z,	(%)):	242	(M+,	100),	241	(M+‐1,	70),	209	
(5.4),	208	(3.2),	183	(32.7),	182	(11.3),	168	(13.8),	154	(27.8),	
140	(46.7),	127	(32.2).	UV	(λ	max,	EtOH):	364.33,	298.17.	

4‐Amino‐5‐(1‐Naphthyl)‐1,2,4‐triazole‐3‐thione	 (2j):	 Yield:	
65%	 (Method	 B).	 M.p.:	 200	 oC.	 IR	 (KBr,	 ν,	 cm‐1):	 3429‐3307	
(NH2),	 1624	 (Ar	 C=C),	 1526	 (C=N),	 1272	 (C=S).	 1H	NMR	 (300	
MHz,	DMSO‐d6,	δ,	ppm):	8.95	(d,	1H,	 J	=	8.5	Hz,	H‐2’’),	8.20	(d,	
1H,	J	=	7.3	Hz,	H‐8’’),	8.06	(d,	1H,	J	=	8.1	Hz,	H‐4’’),	7.56	(m,	4H,	
H‐3’’,	5’’,	6’’,	7’’),	5.61	(s,	2H,	NH2),	13.6	(s,	1H,	NH/SH).	EI‐MS	
(m/z,	(%)):	242	(M+,	100),	241	(M+‐1,	65),	209	(3.4),	208	(4.2),	
183	 (32.4),	 182	 (7.3),	 168	 (12.8),	 154	 (42.8),	 140	 (54.7),	 127	
(68.2).	UV	(λ	max,	EtOH):	360.40,	290.15.	
	
2.2.	Synthesis	of	acetylated	nucleosides	bearing	4‐amino‐5‐
substituted‐1,2,4‐triazole‐3‐thiones	(3a‐j)	
	

General	procedure:	To	a	mixture	of	2	mmoles	of	acetobromo	
sugar	 (2,3,4,6‐tetra‐O‐acetyl‐D‐glucopyranosyl	 bromide),	
mercuric	cyanide	(2	mmoles)	and	anhydrous	calcium	sulfate	or	
molecular	 sieves	 (2	 g),	 was	 added	 1	 mmole	 of	 the	
corresponding	 heterocyclic	 compound.	 In	 each	 case	 the	
reaction	 mixture	 was	 refluxed	 and	monitored	 by	 TLC	 (Silica;	
Ethylacetate:Petroleum	ether,	3:1).	Generally,	the	completion	of	
reaction	occurred	within	5‐6	hours.	Then	the	reaction	mixture	
was	filtered	while	hot	in	order	to	remove	any	insoluble	residue	
which	was	washed	 thoroughly	with	 hotter	 nitromethane.	 The	
filterate	was	evaporated	to	dryness	in	vacuo.	The	product,	thus	
obtained,	 was	 treated	 with	 dichloromethane	 (50‐70	 mL)	 and	
filtered	 to	 remove	 an	 undesired	 solid	 (a	 complex	 formed	 by	
mercuric	halide	and	the	corresponding	heteroyclic	compound).	
The	dichloromethane	extract	was	washed	with	30%	potassium	
iodide	 (50	 mL),	 then	 with	 water	 (30	 mL)	 and	 dried	 over	
anhydrous	 sodium	 sulfate.	 After	 filteration	 the	 solvent	 was	
evaporated	 to	dryness.	 The	 crude	 solid	 obtained	was	purified	
either	by	recrystallization	from	aqueous	ethanol	or	by	column	
chromatography	 (silica	 gel	 (230‐400	 mesh);	 petroleum	
ether:ethylacetate,	4:1)	to	get	pure	products	(Scheme	1).		

(2R,3R,4S,5R)‐(acetoxymethyl)‐6‐(4‐amino‐3‐(pyridin‐2‐yl)‐
5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐2H‐pyran‐
3,4,5‐triyl	triacetate	(3a):	Yield:	67.6%.	M.p.:	174	oC.	IR	(KBr,	ν,	
cm‐1):	3432	(NH2),	1745	(COCH3),	1629	(Ar	C=C),	1592	(C=N),	
1226	 (C=S).	 1H	NMR	 (300	MHz,	DMSO‐d6,	 δ,	 ppm):	1.88,	2.01,	

2.04,	2.10	(4s,	4	x	3H,	4‐CH3),	4.12	(m,	1H,	H‐5’),	4.27	(dd,	1H,	J	
=	2.0	Hz,	12.8	Hz,	H‐6’),	4.50	(dd,	1H,	J	=	4.5	Hz,	12.8	Hz,	H‐6’a),	
5.31	(t,	1H,	J	=	9.8	Hz,	H‐4’),	5.49	(s,	2H,	NH2),	5.65	(t,	1H,	J	=	9.6	
Hz,	H‐3’),	5.88	(t,	1H,	J	=	9.3	Hz,	H‐2’),	6.15	(d,	1H,	J	=	9.2	Hz,	H‐
1’),	7.41	(dt,	1H,	J	=	2.1	Hz,	7.6	Hz,	H‐5’’),	7.62	(t,	1H,	J	=	7.2	Hz,	
H‐4’’),	7.81	(d,	1H,	J	=	4.8Hz,	H‐4’’),	8.05	(d,	1H,	J	=	7.1	Hz,	H‐3’’).		
13C	NMR	(75	MHz,	DMSO‐d6,	δ,	ppm):	20.6,	20.7,	20.8,	20.9	(4‐
CH3),	61.2	(C‐6’),	67.6	(C‐2’),	69.9	(C‐3’),	71.1	(C‐4’),	73.2	(C‐5’),	
83.0	(C‐1’),	130.8	(C‐5’’),	133.5	(C‐6’’),	136.4	(C‐4’’),	145.6	(C‐3’’),	
151.4	 (C‐5),	169.3,	170.0,	170.5,	170.8	 (4‐CO),	171.3	(C‐3).	EI‐
MS	(m/z,	(%)):	523	(M+	5),	193	(5),	456	(2),	453	(1),	331	(12),	
271	(2),	229	(2),	211	(4),	194	(5),	169	(100),	145	(6),	127	(30),	
109	(80),	109	(80),	98	(12),	78	(5).	Anal.	calcd.	for	C21H25N5O9S:	
C,	48.18;	H,	4.78;	N,	13.38.	Found:	C,	48.08;	H,	4.69;	N,	13.40%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(pyridin‐
3‐yl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐
2H‐pyran‐3,4,5‐triyl	triacetate	 (3b):	Yield:	57.2%.	M.p.:	180	oC.	
IR	(KBr,	ν,	cm‐1):	3430	(NH2),	1752	(COCH3),	1588	(C=N),	1224	
(C=S).	 1H	NMR	 (300	MHz,	DMSO‐d6,	 δ,	 ppm):	 1.90,	 2.02,	 2.06,	
2.12(4s,	 4x3H,	 4‐CH3),	 4.14	 (m,	 1H,	 H‐5’),	 4.30	 (m,	 1H,	 H‐6’),	
4.51	(dd,	1H,	J	=	4.6	Hz,	12.6	Hz,	H‐6’a),	5.30	(t,	1H,	J	=	9.5	Hz,	H‐
4’),	5.50	(s,	2H,	NH2),	5.67	(t,	1H,	J	=	9.3	Hz,	H‐3’),	5.89	(t,	1H,	J	=	
9.3	Hz,	H‐2’),	6.15	(d,	1H,	J	=	9.2	Hz,	H‐1’),	7.49	(dd,	1H,	J	=	5.6,	
7.2	Hz,	H‐5‘’),	8.25	(m,	1H,	H‐6’’),	8.60	(d,	1H,	 J	=	5.0Hz,	H‐4’’),	
9.10	 (d,	 1H,	 J	 =	 1.7	 Hz,	 H‐2’’).	 13C	 NMR	 (75	MHz,	 DMSO‐d6,	 δ,	
ppm):	20.3,	20.6,	20.8,	20.9	(4‐CH3),	61.5	(C‐6’),	67.6	(C‐2’),	69.9	
(C‐3’),	71.1	(C‐4’),	73.2	(C‐5’),	83.0	(C‐1’),	130.8	(C‐5’’),	133.5	(C‐
6’’),	136.4	(C‐4’’),	148.6	(C‐2’’),	151.4	(C‐5),	169.3,	170.0,	170.5,	
170.8	 (4‐CO),	 171.3	 (C‐3).	 EI‐MS	 (m/z,	 (%)):	 523	 (M+	 2),	 456	
(1),	331	(15),	271	(5),	236	(7),	211	(7),	202	(4),	193	(12),	169	
(100),	145	(1),	128	(9),	109	(77),	99	(4),	78	(5),	60	(21).	Anal.	
calcd.	 for	 C21H25N5O9S:	 C,	 48.18;	 H,	 4.78;	 N,	 13.38.	 Found:	 C,	
48.12;	H,	4.73;	N,	13.35%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(pyridin‐
4‐yl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐
2H‐pyran‐3,4,5‐triyl	 triacetate	 (3c):	Yield:	69.4%.	M.p.:	176	 oC.	
IR	(KBr,	ν,	cm‐1):	3435	(NH2),	1750	(COCH3),	1588	(C=N),	1224	
(C=S).	 1H	NMR	 (300	MHz,	DMSO‐d6,	 δ,	 ppm):	 1.89,	 2.02,	 2.06,	
2.12	(4s,	4	x	3H,	4‐CH3),	4.02‐4.55	(m,	3H,	H‐5’,	6’,	6’a),	5.33	(t,	
1H,	J	=	9.5	Hz,	H‐4’),	5.42	(bs,	2H,	NH2),	5.69	(t,	1H,	J	=	9.4	Hz,	H‐
3’),	 5.87	 (t,	 1H,	 J	=	9.4	Hz,	H‐2’),	 6.17	 (d,	1H,	 J	 =	9.4	Hz,	H‐1’),	
6.68	(d,	2H,	J	=	8.9	Hz,	H‐2’’,	6’’),	9.21	(d,	2H,	J	=	8.9	Hz,	H‐3’’,	5’’).	
13C	NMR	 (75	MHz,	DMSO‐d6,	 δ,	 ppm):	 20.4,	 20.5,20.7,20.9	 (4–
CH3),	61.2	(C‐6’),	67.5	(C‐2’),	69.2	(C‐3’),	73.4	(C‐4’),	74.5	(C‐5’),	
82.0	 (C‐1’),	 126.1	 (C‐2’’,	 6’’),	 142.6	 (C‐1’’),	 143.7	 (C‐3’’,	 C‐5’’),	
149.2	 (C‐5),	169.1,	169.3,	169.5,	169.9	 (4‐CO),	170.5	(C‐3).	EI‐
MS	(m/z,	(%)):	523	(M+,	3),	456	(2),	453	(1),	331	(14),	271	(3),	
236	(4),	229	(2),	211	(3),	202	(3),	194	(20),	193	(8),	169	(100),	
145	(7),	128	(32),	109	(92),	98	(13),	78	(3),	60	(20).	Anal.	calcd.	
for	 C21H25N5O9S	 (523):	 C,	 48.18;	 H,	 4.78;	 N,	 13.38.	 Found:	 C,	
48.20;	H,	4.76;	N,	13.32%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐5‐thioxo‐3‐
(p‐tolyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐2H‐
pyran‐3,4,5‐triyl	triacetate	(3d):	Yield:	62.9%.	M.p.:	168‐170	oC.	
IR	 (KBr,	 ν,	 cm‐1):	 3468	 (NH2),	 1749	 (COCH3),	 1620	 (Ar	 C=C),	
1588	(C=N),	1225	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	
1.95,	 2.01,	 2.05,	 2.09	 (4s,	 4	 x	 3H,	 4‐CH3),	 2.4	 (s,	 3H,	 CH3‐Ar),	
4.01	(ddd,	1H,	J	=	1.9	Hz,	4.5	Hz,	10.0	Hz,	H‐5’),	4.14	(dd,	1H,	J	=	
1.6	Hz,	12.3	Hz,	H‐6’),	4.29	(dd,	J	=	4.5,	12.3	Hz,	1H,	H‐6’a),	4.92	
(bs,	2H,	NH2),	5.27	(t,	1H,	J	=	9.8	Hz,	H‐4’),	5.42	(t,	J	=	9.4	Hz,	1H,	
H‐3’),	5.88	(t,	J	=	9.3	Hz,	1H,	H‐2’),	6.15	(d,	1H,	J	=	9.2	Hz,	H‐1’),	
7.05	(d,	2H,	J	=	8.4	Hz,	H‐3’’,	5’’),	8.01	(d,	2H,	J	=	7.9	Hz,	H‐2’’,	6’’).	
13C	NMR	(75	MHz,	DMSO‐d6,	δ,	ppm):	20.4,	20.5,	20.6,	20.8	(4‐
CH3),	21.3	(CH3‐Ar),	61.6	(C‐6),	67.6	(C‐2),	69.4	(C‐3),	73.3	(C‐
4),	74.5	(C‐5),	83.1	(C‐1),	121.9	(C‐1),	128.4	(C‐3,	5),	129.1	(C‐2,	
6),	137.2	 (C‐4),	159.6	 (C‐5),	168.8,	169.5,	170.1,	170.4	 (4‐CO),	
178.0	 (C‐3).	 EI‐MS	 (m/z,	 (%)):	 535	 (M+	2),	 331	 (16),	 271	 (5),	
229	 (3),	 211	 (3),	 205	 (13),	 204	 (20),	 189	 (5),	 169	 (100),	146	
(7),	127	 (32),	116	 (16),	109	 (92),	85	 (13),	 68	 (4).	Anal.	 calcd.	
for	C23H28N4O9S:	C,	51.49;	H,	5.22;	N,	10.44.	Found:	C,	51.38;	H,	
5.20;	N,	10.50%.	



488	 Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	
	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐5‐thioxo‐3‐
(3,4,5‐trimethoxyphenyl)‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐
yl)tetrahydro‐2H‐pyran‐3,4,5‐triyl	triacetate	 (3e):	Yield:	59.7%.	
M.p.:	193	oC.	IR	(KBr,	ν,	cm‐1):	3455	(NH2),	1750	(COCH3),	1622	
(Ar	C=C),	1580	(C=N),	1226	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	
δ,	ppm):	1.89,	2.01,	2.04,	2.06	(4s,	4	x	3H	,	4‐CH3),	3.81	(s,	3H,	
OCH3),	3.85(s,	6H,	2‐OCH3),	4.05	(ddd,	1H,	J	=	2.1	Hz,	9.9	Hz,	H‐
5’),	4.16	(1H,	dd,	J	=	2.0	Hz,	12.5	Hz,	H‐6’),	4.32	(1H,	dd,	J	=	4.8,	
12.5	Hz,	H‐6’a),	5.27	(1H,	t,	J	=	9.8	Hz,	H‐4’),	5.39	(1H,	t,	J	=	9.5	
Hz,	H‐3’),	5.80	(s,	2H,	NH2),	5.89	(t,	1H,	J	=	9.4	Hz,	H‐2’),	6.09	(d,	
1H,	 J	 =	 9.2	Hz,	H‐1’),	 7.33	 (s,	 2H,	H‐2”,	 6”).	 13C	NMR	 (75	MHz,	
DMSO‐d6,	 δ,	 ppm):	 20.46,	 20.48,	 20.49,	 20.66	 (4‐CH3),	 56.41	
(OCH3),	61.6	(C‐6),	67.6	(C‐2),	69.3	(C‐3),	73.1	(C‐4),	74.7	(C‐5),	
83.0	(C‐1),	104.0	(C‐2,	6),	116.7	(C‐1),	142.0	(C‐4),	153.7	(C‐3,	
5),	159.4	 (C‐5),	168.9,	169.3,	169.9,	170.4	 (4‐CO),	177.8	 (C‐3).	
EI‐MS	(m/z,	(%)):	611	(1),	331	(14),	271	(4),	229	(2),	211	(1),	
281	(10),	280	(2),	266	(9),	265	(5),	233	 (5),	222	(8),	206	(4),	
203	 (8),	 169	 (100),	167	 (5),	 144	 (7),	 127	 (23),	 116	 (16),	 109	
(92).	 Anal.	 calcd.	 for	 C25H32N4O12S:	 C,	 49.01;	 H,	 5.22;	 N,	 9.15.	
Found:	C,	48.92;	H,	5.15;	N,	9.08%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(4‐fluoro‐
phenyl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐
2H‐pyran‐3,4,5‐triyl	triacetate	(3f):	Yield:	48.6%.	M.p.:	173‐174	
oC.	IR	(KBr,	ν,	cm‐1):	3420	(NH2),	1750	(COCH3),	1620	(Ar	C=C),	
1554	(C=N),	1230	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	
1.89,	2.02,	2.04,	2.06	(4s,	4	x	3H,	4‐CH3),	4.01	(m,	1H,	H‐5’),	4.19	
(dd,	1H,	J	=	1.8,	12.6	Hz,	H‐6’),	4.30	(m,	1H,	H‐6’a),	4.90	(s,	2H,	
NH2),	5.25	(t,	1H,	J	=	9.3	Hz,	H‐4’),	5.40	(t,	1H,	J	=	9.4	Hz,	H‐3’),	
5.88	(t,	1H,	J	=	9.3	Hz,	H‐2’),	6.09	(d,	1H,	J	=	9.2	Hz,	H‐1’),	7.50	(d,	
2H,	J	=	7.8	Hz,	H‐3”,	5”),	8.05	(d,	2H,	J	=	7.8	Hz,	H‐	2”,	6”).	13C	NMR	
(75	MHz,	DMSO‐d6,	δ,	ppm):	20.4,	20.5,	20.6,	20.7	(4‐CH3),	61.5	
(C‐6),	67.6	 (C‐2),	69.2	 (C‐3),	73.2	 (C‐4),	74.7	 (C‐5),	83.0	 (C‐1),	
116.5	 (C‐3,	 5),	 129.2	 (C‐2,	 6),	 158.7	 (C‐5),	 164.0	 (C‐4),	 168.8,	
169.3,	169.9,	170.4	(4‐CO),	177.8	(C‐3).	EI‐MS	(m/z,	(%)):	540	
(3),	 331	 (29),	 271	 (6),	 211	 (4),	 229	 (13),	 187	 (1),	 169	 (100),	
209	(5),	210	(7),	138	(10),	151	(5),	128	(46),	111	(2),	95	(1),	75	
(3).	 Anal.	 calcd.	 for	 C22H25N4O9SF:	 C,	 48.88;	 H,	 4.62;	 N,	 10.37.	
Found:	C,	48.20;	H,	4.59;	N,	10.08%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(4‐chloro‐
phenyl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐
2H‐pyran‐3,4,5‐triyl	 triacetate	 (3g):	Yield:	70.8%.	M.p.:	182	 oC.	
IR	 (KBr,	 ν,	 cm‐1):	 3420	 (NH2),	 1748	 (COCH3),	 1592	 (Ar	 C=C),	
1549	(C=N),	1226	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	
1.88,	2.01,	2.03,	2.04	(4s,	4	x	3H,	4–CH3),	3.97	(m,	1H,	H‐5’),	4.13	
(dd,	1H,	J	=	1.1	Hz,	12.3	Hz,	H‐6’),	4.27	(dd,	1H,	J	=	4.8	Hz,	12.5	
Hz,	H‐6’a),	4.83	(bs,	2H,	NH2),	5.23	(t,	1H,	J	=	9.7	Hz,	H‐4’),	5.39	
(t,	1H,	J	=	9.4	Hz,	H‐3’),	5.85	(t,	1H,	J	=	9.4	Hz,	H‐2’),	6.10	(d,	1H,	
J=9.3	Hz,	H‐1’),	7.43	(d,	2H,	J	=	8.5	Hz,	H‐3’’,	5’’),	8.08	(d,	2H,	J	=	
8.5	 Hz,	 H‐2”,	 6”).	 13C	 NMR	 (75	 MHz,	 DMSO‐d6,	 δ,	 ppm):	 20.2,	
20.4,	20.5,	21.1	(4‐CH3),62.2	(C‐6’),	68.2	(C‐2’),	69.5	(C‐3’),	74.2	
(C‐4’),	 75.1	 (C‐5’),	 83.5	 (C‐1’),	 123.7	 (C‐1”),	 129.6	 (C‐2”,	 6”),	
130.3	 (C‐3,”	 5”),	 138.2	 (C‐4”),	 149.2,(C‐5),	 169.5,	 170.0,	 170.8	
(4‐CO),	 171.3	 (C‐3).	 EI‐MS	 (m/z,	 (%)):	 556	 (1),	 331	 (24),	 269	
(7),	229	(13),	227	(27),	226	(12),	211	(4),	169	(100),	155	(2),	
145	 (6),	 127	 (21),	 109	 (64),	 99	 (2).	 Anal.	 calcd.	 for	
C22H25N4O9SCl:	 C,	 46.68;	 H,	 4.42;	 N,	 9.90.	 Found:	 C,	 46.34;	 H,	
4.40;	N,	9.78%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(4‐bromo	
phenyl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐
2H‐pyran‐3,4,5‐triyl	 triacetate	 (3h):	Yield:	72.4%.	M.p.:	180	 oC.	
IR	 (KBr,	 ν,	 cm‐1):	 3477	 (NH2),	 1752	 (COCH3),	 1622	 (Ar	 C=C),	
1555	(C=N),	1223	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	
1.93,	2.04,	2.08,	2.10	(4s,	4	x	3H,	4‐CH3),	4.05	(ddd,	1H,	J	=	2.1	
Hz,	4.5	Hz,	10.2	Hz,	H‐5’),	4.16	(dd,	1H,	J	=	1.8	Hz,	12.9	Hz,	H‐6’),	
4.31	(dd,	1H,	J	=	5.1	Hz,	12.9	Hz,	H‐6’a),	4.97	(s,	2H,	NH2),	5.28	
(t,	1H,	J	=	9.9	Hz,	H‐4’),	5.44	(t,	1H,	J	=	9.6	Hz,	H‐3’),	5.90	(t,	1H,	J	
=	9.3	Hz,	H‐2’),	6.17	(d,	1H,	J	=	9.3	Hz,	H‐1’),	7.63	(d,	2H,	J	=	8.4	
Hz,	H	3”,	5”),	8.05	(d,	2H,	J	=	8.4	Hz,	H‐2”,	6”).	13C	NMR	(75	MHz,	
DMSO‐d6,	 δ,	ppm):	20.4,	20.5,	20.61,	20.65	 (4‐CH3),	61.5(C‐6’),	
67.6	(C‐2’),	68.8	(C‐3’),	73.5	(C‐4’),	74.7	(C‐5’),	83.0	(C‐1’),	123.3	
(C‐1”),	126.1	(C‐4”),	129.9	(C‐2”,	6”),	132.0	(C‐3”,5”),	149.0	(C‐5),	

168.9,	 169.4,	 169.8,	 170.1	 (4‐CO),	 170.6	 (C‐3).	 EI‐MS	 (m/z,	
(%)):	601	(3),	331	(8),	271	(10),	211	(2),	229	(3),	199	(4),	212	
(2),	156	(7),	169	(100),	127	(90),	145	(1),	109	(60),	99	(3),	75	
(2).	 Anal.	 calcd.	 for	 C22H25N4O9SBr:	 C,	 43.92;	 H,	 4.15;	 N,	 9.31.	
Found:	C,	43.46;	H,	4.10;	N,	9.28%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(naphthalen‐
2‐yl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐2H‐
pyran‐3,4,5‐triyl	 triacetate	 (3i):	 Yield:	 72.1%.	M.p.:	 197	 oC.	 IR	
(KBr,	ν,	cm‐1):	3423	(NH2),	1748	(COCH3),	1624	(Ar	C=C),	1533	
(C=N),	1228	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	1.94,	
1.97,	2.06,	2.09	(4s,	4	x	3H,	4CH3),	4.07	(ddd,	1H,	J	=	2.1	Hz,	4.8	
Hz,	10.1	Hz,	H‐5’),	4.19	(dd,	1H,	J	=	2.4	Hz,	12.6	Hz,	H	‐6’),	4.33	
(dd,	1H,	J	=	5.1	Hz,	12.6	Hz,	H‐6’a),	4.99	(s,	2H,	NH2),	5.31	(t,	1H,	
J	=	9.9	Hz,	H‐	4’),	5.46	(t,	1H,	J	=	9.3	Hz,	H‐3’),	5.99	(t,	1H,	J	=	9.3	
Hz,	H‐2’),	6.19	(d,	1H,	 J	=	9.6	Hz,	H‐1’),	7.59	(m,	2H,	Naphthyl‐
H+),	7.93	(m,	3H,	Naphthyl‐H),	8.12	(dd,	1H,	 J	=	1.3	Hz,	8.7	Hz,	
H‐8”),	8.80	(s,	1H,	H‐1”).	 13C	NMR	(75	MHz,	DMSO‐d6,	δ,	ppm):	
20.4,	20.5,	20.6,	20.7	(4‐CH3),	61.6	(C‐6’),	67.8	(C‐2’),	69.0	(C‐3’),	
73.7	(C‐4’),	74.5	(C‐5’),	83.0	(C‐1’),	124.6(C‐3”),	127.9	(C‐2”,	10”),	
128.4	(C‐5”),	126.8	(C‐7”),	128.9	(C	‐8”),	129.0	(C‐6”),	132.5	(C‐
1”),	134.3	(C‐4”,	9”),	149.4	(C‐5),	168.8,	169.3,	170.1,	170.3	(4‐
CO),	170.6	(C‐3).	EI‐MS	(m/z,	(%)):	572	(M+,6),	512	(3),	469	(2),	
331	(16),	271	(4),	288	(9),	242	 (5),	229	(2),	226	(4),	211	 (4),	
194	 (1),	 169	 (100),	 153	 (8),	 127	 (33),	 126	 (4),	 139	 (2),	 109	
(73),	103	(1).	Anal.	calcd.	for	C26H28N4O9S:	C,	54.54;	H,	4.89;	N,	
9.79.	Found:	C,	53.98;	H,	4.59;	N,	9.60%.	

(2R,3R,4S,5R)‐2‐(acetoxymethyl)‐6‐(4‐amino‐3‐(naphthalen‐
1‐yl)‐5‐thioxo‐4,5‐dihydro‐1H‐1,2,4‐triazol‐1‐yl)tetrahydro‐2H‐
pyran‐3,4,5‐triyl	 triacetate	 (3j):	 Yield:	 69.2%.	M.p.:	 189	 oC.	 IR	
(KBr,	ν,	cm‐1):	3425	(NH2),	1750	(COCH3),	1622	(Ar	C=C),	1552	
(C=N),	1232	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	1.95,	
1.98,	2.02,	2.07	(4s,	4	x	3H,	4CH3),	4.02	(ddd,	1H,	J	=	2.1	Hz,	4.8	
Hz,	10.1	Hz,	H‐5’),	4.15	(dd,	1H,	J	=	2.1	Hz,	12.6	Hz,	H‐6’),	4.29	
(dd,	1H,	J	=	4.8	Hz,	12.6	Hz,	H‐6’a),	5.03	(s,	2H,	NH2),	5.37	(t,	1H,	
J	=	7.6	Hz,	H‐	4’),	5.45	(t,	1H,	J	=	9.6	Hz,	H‐3’),	5.85	(t,	1H,		J	=	9.4	
Hz,	H‐2’),	6.12	(d,	1H,	J	=	9.2	Hz,	H‐1’),	7.60	(m,	4H,	Naphthyl	H),	
8.01	(d,	1H,	J	=	7.2	Hz,	H‐4”),	8.17	(d,	1H,	J	=	8.0	Hz,	H‐8”),	8.80	
(d,	1H,	 J	=	8.1	Hz,	H‐2”).	 13C	NMR	(75	MHz,	DMSO‐d6,	δ,	ppm):	
20.2,	20.4,	20.6,	20.7	 (4‐CH3),	60.9	 (C–6/),	65.8	 (C‐2’),	68.3	 (C‐
3’),	71.7	(C‐4’),	73.5	(C‐5’),	82.0	(C‐1’),	124.6(C‐3”),	128.5	(C‐1”),	
128.4	(C‐5”),	126.8	(C‐7”),	127.9	(C‐2”,	10”),	128.9	(C‐8”),	129.0	
(C‐6”),	 134.3	 (C‐4”,	 9”),	 149.4	 (C‐5),	 168.8,	 169.3,	 170.1,	 170.3	
(4‐CO),	170.6	(C‐3).	EI‐MS	(m/z,	(%)):	572	(M+,	3),	512	(1),	469	
(2),	331	(19),	288	(3),	271	(6),	242	(4),	229	 (3),	211	(7),	194	
(3),	169	(100),	153	(16),	127	(92),	126	(62),	109	(85),	103	(2).	
Anal.	calcd.	for	C26H28N4O9S:	C,	54.54;	H,	4.89;	N,	9.79.	Found:	C,	
54.68;	H,	4.75;	N,	9.72%.	
	
2.3.	Synthesis	of	deprotected	nucleosides	(4a‐j)	
	

General	 procedure:	 Each	 of	 the	 protected	 nucleoside	 (1	
mmole)	 was	 dissolved	 in	 dry	 methanol	 and	 a	 fairly	 rapid	
stream	 of	 dry	 ammonia	 was	 passed	 into	 the	 solution	 for	 3‐4	
hours.	During	this	period	the	reaction	mixture	was	kept	stirred.	
The	completion	of	 reaction	was	checked	by	TLC.	The	solution	
was	kept	for	24	hours	at	0‐4	oC.	Removal	of	the	solvent	in	vacuo	
yielded	 a	 sirup	 which	 was	 dissolved	 in	 dry	 ethanol	 and	
recrystallised	 by	 adding	 a	 few	 drops	 of	 ethyl	 acetate	 or	 the	
product	 was	 purified	 by	 column	 chromatography	 (silica	 gel	
(230‐400	 mesh);	 chloroform:methanol,	 3:1)	 to	 get	 pure	
products	(Scheme	1).		

4‐Amino‐3‐(pyridin‐2‐yl)‐1‐((3R,4S,5S,6R)‐3,4,5‐trihydroxy‐
6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐triazole‐
5(4H)‐thione	 (4a):	 Yield:	 46.6%.	 M.p.:	 142	 oC	 (Decomp.).	 IR	
(KBr,	 ν,	 cm‐1):	 3410	 (NH2),	 2970‐3100	 (br	 peak	 OH),	 1586	
(C=N),	1225	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	3.78‐
4.08	 (m,	3H,	H‐5’,	H‐6’/6’a),	4.58	 (d,	1H,	 J	=	8.5	Hz,	H‐3’),	 4.62	
(m,	 1H,	H‐4’),	 5.02	 (d,	 1H,	 J	=	 9.1	Hz,	 H‐2’),	 5.43	 (s,	 2H,	NH2),	
5.51	(bs,	4H,	4‐OH),	6.02	(d,	1H,	J	=	9.0	Hz,	H‐1’),	7.52	(d,	1H,	J	=	
7.5	Hz,	H‐4’’),	7.75	(m,	1H,	H‐5’’),	7.95	(d,	1H,	 J	=	7.6	Hz,	H‐6’’),	
8.20	 (s,	1H,	H‐3’’).	 FAB‐MS	 (m/z,	 (%)):	355	 ((M+	+	H,	30),	193	



Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	 489	
 

(67).	 Anal.	 calcd.	 for	 C13H17N5O5S:	 C,	 43.94;	 H,	 4.78;	 N,	 19.71.	
Found:	C,	43.85;	H,	4.65;	N,	19.80%.	

4‐Amino‐3‐(pyridin‐3‐yl)‐1‐((3R,4S,5S,6R)‐3,4,5‐trihydroxy‐
6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐triazole‐
5(4H)‐thione	 (4b):	 Yield:	 41.3%.	 M.p.:	 142	 oC	 (Decomp.).	 IR	
(KBr,	 ν,	 cm‐1):	 3372	 (NH2),	 2980‐3055	 (br	 peak	 OH),	 1584	
(C=N),	1228	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	3.98‐
4.18	(m,	3H,	H‐5’,	H‐6’/6’a),	4.52	(m,	1H,	H‐4’),	4.78	(d,	1H,	J	=	
8.5	Hz,	H‐3’),	 4.98	 (d,	 1H,	 J	 =	 9.1	Hz,	 H‐2’),	 5.49	 (s,	 2H,	NH2),	
5.30	(bs,	4H,	4‐OH),	5.95	(d,	1H,	J	=	9.0	Hz,	H‐1’),	7.43	(m,	1H,	H‐
5’’),	7.65	(d,	1H,	J	=	7.6	Hz,	H‐6’’),	7.91	(s,	1H,	H‐2’’),	8.09	(d,	1H,	
7.5	Hz,	H‐4’’).	FAB‐MS	(m/z,	(%)):	355	(M+	+	H,	17),	193	(100).	
Anal.	calcd.	for	C13H17N5O5S:	C,	43.94;	H,	4.78;	N,	19.71.	Found:	
C,	43.89;	H,	4.69;	N,	19.71%.	

4‐Amino‐3‐(pyridin‐4‐yl)‐1‐((3R,4S,5S,6R)‐3,4,5‐trihydroxy‐
6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐triazole‐
5(4H)‐thione	(4c):	Yield:	49.1%.	M.p.:	161‐163	oC	(Decomp.).	IR	
(KBr,	 ν,	 cm‐1):	 3410	 (NH2),	 2980‐3254	 (br	 peak	 OH),	 1584	
(C=N),	1224	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	3.76‐
3.84	(m,	3H,	H‐5’,	H‐6’/6’a),	4.24	(d,	1H,	J	=	7.8	Hz,	H‐4’),	4.52	(d,	
1H,	J	=	6.5,	Hz,	8.1	Hz,	H‐3’),	4.98	(bs,	2H,	NH2),	5.41	(bs,	4H,	4‐
OH),	5.83	(d,	1H,	J	=	8.6	Hz,	H‐2’),	6.12	(d,	1H,	J	=	8.3	Hz,	H‐1’),	
7.38	(dd,	2H,	J	=	2.1	Hz,	7.8	Hz,	H‐2’’,	6’’),	8.29	(dd,	2H,	J	=	2.3	Hz,	
7.6	Hz,	H‐3’’,	5’’).	FAB‐MS	(m/z,	(%)):	355	(M+	+	H,	60),	193	(88).		
Anal.	calcd.	for	C13H17N5O5S:	C,	43.94;	H,	4.78;	N,	19.71.	Found:	
C,	43.87;	H,	4.75;	N,	19.66%.	

4‐Amino‐3‐(p‐tolyl)‐1‐((3R,4S,5S,6R)‐3,4,5‐trihydroxy‐6‐
(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐triazole‐
5(4H)‐thione	(4d):	Yield:	48.5%.	M.p.:	177‐179	oC	(Decomp.).	IR	
(KBr,	 ν,	 cm‐1):	 3398	 (NH2),	 2980‐3054	 (br	 peak	 OH),	 1554	
(C=N),	1228	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	2.3	(s,	
3H,	CH3),	3.80‐4.05	(m,	3H,	H‐5’,	H‐6’/6’a),	4.49	(dd,	1H,	J	=	6.5	
Hz,	8.1	Hz,	H‐3’),	4.64	(d,	1H,	J	=	7.8	Hz,	H‐4’),	4.98	(bs,	2H,	NH2),	
5.33	(bs,	4H,	4‐OH),	5.69	(d,	1H,	J	=	8.6	Hz,	H‐2’),	6.12	(d,	1H,	J	=	
8.3	Hz,	H‐1’),	7.28‐7.34	(m,	4H,	Ar‐H).	FAB‐MS	(m/z,	(%)):	369	
(M+	+	H,	26),	207	(100).	Anal.	calcd.	 for	C15H20N4O5S:	C,	48.91;	
H,	5.43;	N,	15.21.	Found:	C,	48.87;	H,	5.41;	N,	15.06%.	

4‐Amino‐1‐((3R,4S,5S,6R)‐3,4,5‐trihydroxy‐6‐(hydroxyl	
methyl)tetrahydro‐2H‐pyran‐2‐yl)‐3‐(3,4,5‐trimethoxyphenyl)‐
1H‐1,2,4‐triazole‐5(4H)‐thione	(4e):	Yield:	43.5%.	M.p.:	142‐145	
oC	 (Decomp.).	 IR	 (KBr,	 ν,	 cm‐1):	 3408	 (NH2),	 2980‐3024	 (br	
peak	OH),	1556	(C=N),	1225	(C=S).	1H	NMR	(300	MHz,	DMSO‐
d6,	 δ,	 ppm):	 1.92	 (s,	 9H,	 3	 x	OCH3),	 3.73‐3.80	 (m,	 3H,	H‐5’,	H‐
6’/6’a),	4.32	(d,	1H,	J	=,	8.1	Hz,	H‐4’),	4.41	(m,	1H,	H‐3’),	4.89	(d,	
1H,	J	=	8.5	Hz,	H‐2’),	5.10	(bs,	2H,	NH2),	5.47	(bs,	4H,	4‐OH),	5.98	
(d,	1H,	J	=	8.6	Hz,	H‐1’),	6.95	(s,	2H,	H‐2’’,6’’).	FAB‐MS	(m/z,	(%)):	
445	 ((M+	 +	 H,	 76),	 283	 (94).	 Anal.	 calcd.	 for	 C17H24N4O8S:	 C,	
45.94;	H,	5.40;	N,	12.6.	Found:	C,	45.87;	H,	5.38;	N,	12.45%.		

4‐Amino‐3‐(4‐fluorophenyl)‐1‐((3R,4S,5S,6R)‐3,4,5‐tri‐
hydroxy‐6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐
triazole‐5(4H)‐thione	 (4f):	 Yield:	 50.2%.	 M.p.:	 145‐147	 oC	
(Decomp.).	 IR	 (KBr,	 ν,	 cm‐1):	3879	 (NH2),	2960‐3150	 (br	peak	
OH),	1588	(C=N),	1227	(C=S).	 1H	NMR	(300	MHz,	DMSO‐d6,	δ,	
ppm):	3.70‐3.98	(m,	3H,	H‐5’,	H‐6’/6’a),	4.52	(d,	1H,	 J	=	7.8	Hz,	
H‐4’),	4.75	(m,	1H,	H‐3’),	5.09	(d,	1H,	J	=	8.3	Hz,	H‐2’),	5.13	(bs,	
2H,	NH2),	5.32	(bs,	4H,	4‐OH),	5.94	(d,	1H,	J	=	8.4	Hz,	H‐1’),	7.18‐
7.38	(m,	4H,	Ar‐H).	FAB‐MS	(m/z,	 (%)):	373	(M+	+	H,	36),	211	
(77).	Anal.	 calcd.	 for	C14H17N4O5SF:	C,	45.16;	H,	4.56;	N,	15.06.	
Found:	C,	45.07;	H,	4.52;	N,	15.03%.	

4‐Amino‐3‐(4‐chlorophenyl)‐1‐((3R,4S,5S,6R)‐3,4,5‐tri‐
hydroxy‐6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐
1,2,4‐triazole‐5(4H)‐thione	 (4g):	Yield:	48.2%.	M.p.:	150‐153oC	
(Decomp.).	 IR	 (KBr,	 ν,	 cm‐1):	3409	 (NH2),	2960‐3250	 (br	peak	
OH),	1585	(C=N),	1225	(C=S).	 1H	NMR	(300	MHz,	DMSO‐d6,	δ,	
ppm):	3.95‐4.03	(m,	3H,	H‐5’,	H‐6’/6’a),	4.51	(d,	1H,	 J	=	7.6	Hz,	
H‐4’),	4.65	(d,	1H,	 J	=	8.5	Hz,	H‐3’),	5.05	(bs,	2H,	NH2),	5.29	(d,	
1H,	J	=	8.1	Hz,	H‐2’),	5.41	(bs,	4H,	4‐OH),	5.98	(d,	1H,	J	=	8.2	Hz,	
H‐1’),	7.12‐7.26	(m,	4H,	Ar‐H).	FAB‐MS	(m/z,	(%)):	388	(M+	+	H,	
46),	226	(100).	Anal.	calcd.	for	C14H17N4O5SCl:	C,	43.24;	H,	4.37;	
N,	14.41.	Found:	C,	43.20;	H,	4.30;	N,	14.50%.	

4‐Amino‐3‐(4‐bromophenyl)‐1‐((3R,4S,5S,6R)‐3,4,5‐tri‐
hydroxy‐6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐
triazole‐5(4H)‐thione	 (4h):	 Yield:	 51.2%.	 M.p.:	 153‐156	 oC	
(Decomp.).	 IR	 (KBr,	 ν,	 cm‐1):	3408	 (NH2),	2960‐3252	 (br	peak	
OH),	1580	(C=N),	1224	(C=S).	 1H	NMR	(300	MHz,	DMSO‐d6,	δ,	
ppm):	3.70‐3.86	(m,	3H,	H‐5’,	H‐6’/6’a),	4.20	(d,	1H,	J	=	7.2	Hz,	
H‐4’),	4.48	(m,	1H,	H‐3’),	4.90	(s,	2H,	NH2),	5.39	(bs,	4H,	4‐OH),	
5.52	(d,	1H,	J	=	8.9	Hz,	H‐2’),	6.20	(d,	1H,	J	=	9.0	Hz,	H‐1’),	7.19‐
7.32	(m,	4H,	Ar‐H).	FAB‐MS	(m/z,	 (%)):	433	(M+	+	H,	21),	271	
(56).	Anal.	calcd.	for	C14H17N4O5SBr:	C,	38.79;	H,	3.92;	N,	12.93.	
Found:	C,	38.75;	H,	3.95;	N,	3.95%.	

4‐Amino‐3‐(naphthalen‐2‐yl)‐1‐((3R,4S,5S,6R)‐3,4,5‐tri‐
hydroxy‐6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐
triazole‐5(4H)‐thione	 (4i):	 Yield:	 47.8%.	 M.p.:	 150‐151	 oC	
(Decomp.).	 IR	 (KBr,	 ν,	 cm‐1):	3418	 (NH2),	2908‐3272	 (br	peak	
OH),	1580	(C=N),	1240	(C=S).	 1H	NMR	(300	MHz,	DMSO‐d6,	δ,	
ppm):	3.67‐3.85	(m,	3H,	3H,	H‐5’,	H‐6’,	H‐6’a),	4.35	(m,	1H,	H‐4’),	
4.58	(d,	1H,	J	=	7.8	Hz,	H‐3’),	4.96	(s,	2H,	NH2),	5.38	(d,	1H,	 J	=	
8.0	Hz,	H‐2’),	5.43	(bs,	4H,	4‐OH),	5.91	(d,	1H,	J	=	8.0	Hz,	H‐1’),	
7.80‐8.21	(m,	7H,	Naphthyl‐H).	FAB‐MS	(m/z,	(%)):	405	(M+	+H,	
32),	243	(68).	Anal.	calcd.	for	C18H20N4O5S:	C,	53.46;	H,	4.95;	N,	
13.86.	Found:	C,	53.51;	H,	3.91;	N,	13.84%.	

4‐Amino‐3‐(naphthalen‐1‐yl)‐1‐((3R,4S,5S,6R)‐3,4,5‐tri‐
hydroxy‐6‐(hydroxymethyl)tetrahydro‐2H‐pyran‐2‐yl)‐1H‐1,2,4‐
triazole‐5(4H)‐thione	(4j):	Yield:	53.8%.	M.p.:	156	oC	(Decomp.).	
IR	 (KBr,	 ν,	 cm‐1):	 3409	 (NH2),	 2932‐3268	 (br	peak	OH),	 1585	
(C=N),	1238	(C=S).	1H	NMR	(300	MHz,	DMSO‐d6,	δ,	ppm):	3.73‐
3.95	(m,	3H,	H‐5’,	H‐6’,	H‐6’a),	4.42	(m,	1H,	H‐4’),	4.60	(d,	1H,	J	=	
7.5	Hz,	H‐3’),	5.01	(s,	2H,	NH2),	5.28	(d,	1H,	J	=	8.4	Hz,	H‐2’),	5.35	
(bs,	4H,	4‐OH),	5.78	(d,	1H,	 J	=	8.5	Hz,	H‐1’),	7.85‐8.20	(m,	7H,	
Naphthyl‐H).	 FAB‐MS,	m/z	 (%):	 405	 (M+	 +	 H,	 26),	 243	 (83).	
Anal.	calcd.	for	C18H20N4O5S:	C,	53.46;	H,	4.95;	N,	13.86.	Found:	
C,	53.45;	H,	3.90;	N,	13.82%.	
	
2.4.	Antibacterial	activity		
	

In	vitro	 evaluation	of	antibacterial	activity	of	 the	4‐amino‐
5‐substituted‐1,2,4‐triazole‐3‐thiones	 (2a‐j)	 and	 there	
corresponding	 protected	 (3a‐j)	 and	 deprotected	 nucleosides	
(4a‐j)	was	carried	out	by	agar	well	diffusion	assay	against	ten	
different	Gram	positive	(Bacillus	subtilis,	Staphylococcus	aureus	
and	Micrococcus	 luteus)	 and	Gram	negative	 (Proteus	mirabilis,	
Escherichia	coli,	Pseudomonas	putida,	Pseudomonas	aeruginosa,	
Salmonalla	 typhi,	 Shigella	 flexineri	 and	Klebsiella	 pneumoniae)	
bacteria	 [19].	 Antibacterial	 activity	 was	 determined	 by	 using	
the	Mueller	Hinton	Agar	 (MHA).	The	 fresh	 inoculums	of	 these	
bacteria	were	prepared	and	diluted	by	sterilized	normal	saline.	
The	 turbidity	 of	 these	 cultures	was	 adjusted	by	using	0.5	Mc‐
Farland.	 A	 homogeneous	 bacterial	 lawn	 was	 developed	 by	
sterile	 cotton	 swabs.	 The	 inoculated	 plates	 were	 bored	 by	 6	
mm	sized	borer	 to	make	 the	wells.	The	sample	dilutions	were	
prepared	by	dissolving	each	sample	(1.0	mg)	in	1.0	mL	of	DMSO	
used	 as	 negative	 control	 in	 this	 bioassay.	 The	 equimolar	
concentration	of	Levofloxacin	 (1.0	mg/mL),	 a	broad	 spectrum	
antibiotic	 (positive	 control)	 was	 prepared.	 These	 plates	were	
incubated	at	37	°C	for	24	hours.	Antibacterial	activity	of	these	
three	 series	 of	 compounds	was	determined	 by	measuring	 the	
diameter	of	zone	of	 inhibition	(mm,	±	standard	deviation)	and	
presented	by	subtracting	the	activity	of	the	negative	control.		
	
3.	Results	and	discussion	
	
3.1.	Synthesis	
	

Ten	 5‐substituted‐4‐amino‐1,2,4‐triazole‐3‐thiones	 (2a‐g)	
were	 synthesized	 by	 the	 reaction	 of	 either	 potassium	 salts	 of	
oxadiazoles	 or	 the	 corresponding	 oxadiazoles	 with	 hydrazine	
hydrate.		

	
	
	
	



490	 Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	
	

	

	

Scheme	2	
	
	
Two	different	reaction	routes	are	followed	for	the	synthesis	

of	 said	 compounds	 (Scheme	 1	 and	 2).	 The	 yield	 in	 case	 of	
hydrazine	 hydrate	 (99%)	 with	 oxadiazoles	 (Method	 B)	 was	
good	as	compared	to	Method	A.	

Most	 of	 the	 methods	 reported	 for	 the	 preparations	 of	
nucleosides	afforded	the	mixture	of	α	and	β‐glycosides.	But	the	
method	 adopted	 for	 the	 synthesis	 of	 target	 nucleosides	
furnished	 only	 β‐isomer.	 The	 stereochemistry	 of	 the	 final	
products	was	confirmed	by	1,2‐diaxial	coupling	constants	in	1H	
NMR	 spectra.	 The	 reaction	was	 found	 to	 be	 quite	 convenient	
giving	 moderate	 to	 high	 yields.	 Each	 one	 of	 the	 synthesized	
triazoles	was	subjected	to	an	identification	test	with	ninhydrin	
solution	and	appearance	of	yellow	colour	gave	the	indication	of	
4‐aminotriazole.	 The	 structures	 of	 the	 synthesized	 amino	
triazoles	(2a‐j)	were	confirmed	by	spectroscopic	data.	A	broad	
peak	 appeared	 at	 3330‐3430	 cm‐1	 indicated	 the	 presence	 of								
‐NH2	group	in	the	molecule.	The	absorption	at	1642‐1630	cm–1	
was	 attributed	 to	 C=N	 and	 C=S	 stretching	 vibrations	 were	
observed	at	1218‐1268	cm‐1.		

In	1H	NMR	a	singlet	appeared	at	5.43‐5.81	ppm	integrating	
to	2H	for	‐NH2	protons.	In	the	pyridyl	bearing	triazoles	(2a‐c),	
the	pyridyl	protons	resonated	as	expected	for	these	protons	e.g.	
H‐5	 exhibited	 a	 doublet	 of	 a	 doublet	 in	 the	 region	 7.37‐7.83	
ppm.	 In	 compounds	 (2f‐h),	 the	 aromatic	 protons	 H‐2,	 6	
resonated	 downfield	 at	 7.93‐8.05	 ppm	 as	 doublet	 due	 to	
electron	withdrawing	effects	of	C=N	group	while	doublet	for	H‐
3,	5	was	observed	at	7.20‐7.63	ppm	due	to	electron	donating	
effect	 of	 halogen	 atoms.	 In	 all	 the	 amino	 triazoles	 (2a‐j),	 the	
molecular	ion	peak	was	the	base	peak	with	100%	intensity.	The	
fragment	ions	are	also	in	good	agreement	with	the	structures.		

The	 substituted	 aminotriazoles	 (2a‐j)	 were	 coupled	 with	
acetylated	 ‐bromoglucose	 in	 presence	 of	 mercuric	 cyanide	
and	molecular	 sieves	 using	 nitromethane	 as	 solvent	 to	 afford	
the	 corresponding	 nucleosides	 (3a‐j).	 The	 IR	 spectra	 of	
nucleosides	(3a‐j)	exhibited	a	band	at	1745‐1752	cm‐1	 for	 the	
carbonyl	 stretching	 of	 acetyl	 groups	 and	 the	 NH2	 group	
stretchings	 vibration	 observed	 in	 the	 region	 3310‐3432	 cm‐1.	
The	protons	of	acetyl	groups	appeared	as	singlets	in	the	region	
1.88‐2.12	ppm	in	1H	NMR	spectra	of	amino	triazole	nucleosides	
(3a‐j).	The	anomeric	proton	resonated	as	doublet	in	the	range	
6.09‐6.19	 ppm	 with	 a	 coupling	 constant	 of	 9‐10	 Hz	 which	
clearly	 indicates	 the	 diaxial	 orientation	 of	 H‐1	 and	 H‐2	
confirming	the	‐configuration	of	these	acetylated	nucleosides.	
The	 triplets	 for	 H‐2	 were	 observed	 in	 the	 region	 5.85‐5.99	
ppm.	In	all	the	compounds	(3a‐j),	a	singlet	of	two	protons	was	
observed	in	the	region	4.83‐5.50,	corresponding	to	the	protons	
of	amino	group.		

In	13C	NMR	spectra	of	compounds	(3a‐j)	the	methyl	carbon	
atoms	of	acetyl	groups	resonated	in	the	region	20.2‐21.2	ppm.	
The	carbonyl	carbon	atoms	resonated	downfield	at	168.8‐170.8	
ppm.	 The	 anomeric	 carbon	 atom	 in	 all	 these	 compounds	

appeared	 at	 82.0‐83.5	 ppm	 indicating	 its	 linkage	 to	 nitrogen	
atom	 of	 heterocyclic	moiety.	 The	 C‐3	 carbon	 (C=S)	 resonated	
downfield	 at	 170.5‐171.3	 ppm.	 Mass	 spectral	 data	 of	 these	
compounds	further	confirmed	the	structure	of	the	compounds.	
In	 the	 mass	 spectra	 of	 compound	 (3a‐j),	 the	 molecular	 ion	
peaks	 appeared	 with	 low	 intensities	 (1‐6%).	 In	 compounds	
(3a‐c),	 the	 loss	of	heterocyclic	moiety	 from	 the	molecular	 ion	
yielded	a	peak	at	m/z	331,	and	the	successive	loss	of	CH3COOH	
and	CH2=C=O	molecules	from	this	peak	furnished	the	base	peak	
at	m/z	169.	The	loss	of	sugar	molecule	from	the	molecular	ion	
yielded	the	stable	triazole	cation	radical	at	m/z	193.		

Acetylated	 4‐amino‐5‐substituted‐1,2,4‐triazole	 glucosides	
(3a‐j)	 were	 deprotected	 successfully	 using	 methanolic	
ammonia	 giving	 N‐(‐D‐Glucopyranosyl)‐4‐amino‐5‐substi‐
tuted‐1,2,4‐triazole‐3‐thiones	 (4a‐j).	 The	 deacetylation	 of	
nucleosides	 was	 confirmed	 by	 FT‐IR,	 1H	 NMR,	 FAB‐MS	 and	
elemental	analysis	data	for	these	compounds.	

The	FT‐IR	spectra	showed	no	peak	for	carbonyl	stretching	
indicating	complete	deaceylation	of	acetylated	nucleosides.	The	
N‐H	stretching	vibrations	of	NH2	group	were	observed	at	3100‐
3410	cm‐1.	Also	a	peak	for	C=S	stretchings	was	found	at	1224‐
1225	 cm‐1.	 The	 absence	 of	 methyl	 protons	 signal	 of	 acetyl	
groups	 in	 1H	 NMR	 spectra	 of	 deprotected	 nucleosides	 (4a‐j)	
confirm	 the	 complete	 removal	 of	 acetyl	 groups.	 Anomeric	
proton	H‐1	also	resonated	as	doublet	with	coupling	constant	of	
8‐9	Hz,	which	indicated	diaxial	orientation	of	H‐1	and	H‐2	and	
confirmed	 ‐configuration	 of	 these	 nucleosides.	 The	 13C	 NMR	
spectral	 data	 also	 supported	 the	 deacetylation	 of	 nucleosides	
(4a‐j).	No	signals	for	methyl	carbon	atoms	and	carbonyl	carbon	
atoms	 of	 acetyl	 groups	 were	 observed.	 The	 remaining	 sugar	
carbon	atoms	resonated	in	the	range	61.9‐87.2	ppm,	similar	to	
acetylated	glucosides.	The	elemental	analysis	data	also	proved	
the	 deacetylation	 of	 blocked	 nucleosides.	 This	 data	 showed	
good	agreement	between	the	calculated	and	found	percentages	
of	 carbon,	 hydrogen	 and	 nitrogen	 for	 the	 deacetylated	
products.	
	
3.2.	Antimicrobial	bioassay	
	

Biological	activity	of	a	compound	is	a	function	of	the	nature	
and	 extent	 of	 interactions	 between	 the	 target	 site	 and	
functional	 groups	 of	 the	 compound.	 A	 range	 of	 structural	
features	 present	 in	 the	 molecule	 like	 electronegativity	 and	
hydrophobicity	 are	 the	 important	 determining	 factors.	
Molecules	 with	 high	 HOMO	 (highest	 occupied	 molecular	
orbital)	energies	are	more	proficient	 to	donate	 their	electrons	
and	are	good	hydrogen	bond	donors	than	molecules	with	low‐
lying	HOMOs;	thus	HOMO	is	a	measure	of	the	ability	to	develop	
hydrogen	bonding	with	target	site.	However,	structure	activity	
relationship	 cannot	 be	 established	 on	 the	 basis	 of	 single	
structural	feature.	



Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	 491	
 

	
Table	1.	Anti‐bacterial	activity	results	of	aminotriazoles	(2a‐j)	*.	
Compound	 Anti‐bacterial	activity,	mm	

Proteus	
mirabilis	

Bacillus	
subtilis	

Escherichia	
coli	

Staphylococcus	
aureus	

Pseudomonas	
putida	

Pseudomonas	
aeruginosa	

Salmonella	
typhi	

Micrococcus	
luteus	

Shigella	
flexneri	

Klebsiella	
pneumoniae

2a	 10	 12	 ‐	 13	 06	 ‐	 ‐	 12	 ‐	 ‐	
2b	 ‐	 10	 11	 17	 ‐ 06 08 13 04	 07
2c	 05	 19	 07	 15	 ‐ ‐ ‐ 15 ‐	 ‐
2d	 ‐	 09	 ‐	 11	 11 ‐ ‐ 11 07	 11
2e	 11	 18	 ‐	 22	 ‐ 08 ‐ 21 ‐	 ‐
2f	 ‐	 17	 ‐	 20	 ‐ ‐ 05 20 ‐	 ‐
2g	 ‐	 15	 06	 18	 10 ‐ ‐ 17 10	 08
2h	 ‐	 14	 ‐	 16	 ‐	 05	 ‐	 16	 ‐	 ‐	
2i	 08	 08	 06	 10	 10	 ‐	 ‐	 09	 11	 ‐	
2j	 ‐	 11	 ‐	 07	 05	 09	 ‐	 10	 ‐	 ‐	
Standard	 30	 20	 30	 25	 30 28 30 25 30	 25
*	Standard=	Levofloxacin;	(‐)	No	activity.	
	
Table	2.	Anti‐bacterial	activity	results	of	acetylated	N‐nucleosides	(3a‐j)	*.	
Compound	 Anti‐bacterial	activity,	mm

Proteus	
mirabilis	

Bacillus	
subtilis	

Escherichia	
coli	

Staphylococcus	
aureus	

Pseudomonas	
putida	

Pseudomonas	
aeruginosa	

Salmonella	
typhi	

Micrococcus	
luteus	

Shigella	
flexneri	

Klebsiella	
pneumoniae

3a	 19	 ‐	 18	 ‐	 16 12 19 ‐ 16	 10
3b	 23	 08	 21	 07	 18	 15	 21	 04	 20	 12	
3c	 27	 ‐	 25	 ‐	 26	 19	 25	 ‐	 24	 17	
3d	 ‐	 ‐	 08	 11	 ‐ ‐ ‐ 07 05	 ‐
3e	 02	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	 ‐	
3f	 16	 05	 14	 ‐	 10	 10	 05	 ‐	 15	 12	
3g	 18	 ‐	 19	 08	 13 13 10 10 17	 18
3h	 20	 ‐	 22	 ‐	 17 16 18 ‐ 21	 21
3i	 10	 07	 ‐	 ‐	 ‐ ‐ ‐ 11 ‐	 ‐
3j	 07	 ‐	 05	 ‐	 ‐ 06 ‐ ‐ 05	 ‐
Standard	 30	 20	 30	 25	 30 28 30 25 30	 25
*	Standard=	Levofloxacin;	(‐)	No	activity.	
	
Table	3.	Anti‐bacterial	activity	results	of	deacetylated	N‐nucleosides	(4a‐j)	*.	
Compound	 Anti‐bacterial	activity,	mm	

Proteus	
mirabilis	

Bacillus	
subtilis	

Escherichia	
coli	

Staphylococcus	
aureus	

Pseudomonas	
putida	

Pseudomonas	
aeruginosa	

Salmonella	
typhi	

Micrococcus	
luteus	

Shigella	
flexneri	

Klebsiella	
pneumoniae

4a	 19	 ‐	 20	 ‐	 16 12 19 ‐ 16	 10
4b	 21	 08	 23	 07	 18 15 21 04 20	 12
4c	 24	 ‐	 26	 ‐	 26 19 25 ‐ 24	 17
4d	 ‐	 ‐	 ‐	 11	 ‐ ‐ ‐ 07 05	 ‐
4e	 28	 18	 27	 22	 25 22 27 22 26	 20
4f	 ‐	 16	 04	 18	 10 10 05 17 15	 ‐
4g	 ‐	 18	 ‐	 20	 13 13 10 19 17	 08
4h	 ‐	 20	 ‐	 22	 17	 16	 18	 21	 21	 ‐	
4i	 10	 07	 ‐	 ‐	 ‐	 ‐	 ‐	 11	 ‐	 ‐	
4j	 07	 ‐	 05	 ‐	 ‐	 06	 ‐	 ‐	 05	 ‐	
Standard	 30	 20	 30	 25	 30 28 30 25 30	 25
*	Standard=	Levofloxacin;	(‐)	No	activity.	
	
	
	
3.3.	Antibacterial	activity		
	

The	 antibacterial	 activity	 results	 revealed	 that	 4‐amino‐5‐
substituted‐1,2,4‐triazole‐3‐thiones	 (2a‐j)	 exhibited	 moderate	
to	 potent	 bacterial	 growth	 inhibition	 against	 gram	 positive	
bacterial	 strains	 but	 most	 of	 them	 are	 inactive	 against	 gram	
negative	strains	(Table	1).	It	was	also	found	that	anti‐bacterial	
activity	 was	 dependant	 on	 the	 type	 and	 position	 of	 the	
substituent	 present	 on	 5‐aromatic	 ring.	 4‐Amino‐5‐(3,4,5‐
trimethoxyphenyl)‐1,2,4‐triazole‐3‐thiones	 (2e)	 is	 the	 most	
active	 among	 this	 series.	 The	 compounds	 which	 possess	
halogen	substituted	5‐phenyl	ring	are	more	active	than	methyl	
substituted	and	also	naphthyl.	The	antibacterial	activity	of	the	
halogen	 substituted	 analogues	 is	 directly	 related	 to	 the	
electronegativity	of	the	halogens.	4‐Amino‐5‐(4‐flourophenyl)‐
1,2,4‐triazole‐3‐thiones	 (2f)	 exhibited	 excellent	 bacterial	
growth	 inhibition	 than	 chloro	 substituted	 and	 bromo	
substituted	 5‐phenyl	 ring.	 It	 may	 be	 due	 to	 the	 greater	
electronegativity	 of	 halogen	 make	 the	 carbon‐halogen	 bond	
more	polar	which	help	in	receptor	binding.		

The	 acetylated	 nucleoside	 analogues	 (3a‐j)	 of	 4‐amino‐5‐
substituted‐1,2,4‐triazole‐3‐thiones	 have	 high	 potential	
towards	 bacterial	 growth	 inhibition	 than	 4‐amino‐5‐
substituted‐1,2,4‐triazole‐3‐thiones	 (2a‐j).	 The	 protected	
nucleosides	(3a‐j)	unlike	aminotriazoles	(2a‐j)	are	more	active	

against	 gram	 negative	 bacteria	 than	 gram	 positive	 (Table	 2).	
The	acetylated	nucleosides	which	possess	5‐pyridyl	ring	(3a‐c)	
showed	potent	antibacterial	activity	and	the	compounds	having	
halogen	 substituted	 5‐phenyl	 ring	 (3f‐h)	 also	 portray	 good	
bacterial	growth	inhibition.	 In	these	compounds	the	protected	
sugar	 moiety	 and	 heterocyclic	 pyridine	 ring	 is	 critical	 for	
antibacterial	 activity	 against	 gram	 negative	 microorganisms.	
The	 nucleoside	 (3c)	 possess	 4‐pyridyl	 ring	 is	 most	 active	
against	 tested	 gram	negative	bacteria	 than	 compound	3a	 and	
3b	 having	 2‐pyridine	 and	 3‐pyridine	 ring	 respectively.	 The	
nucleoside	 (3c)	actually	have	 less	 sterically	 crowded	pyridine	
ring	than	compounds	(3a)	and	(3b)	which	play	important	role	
in	antibacterial	activity.	The	activity	of	the	halogen	substituted	
nucleosides	can	again	be	correlated	 to	 the	electronegativity	of	
the	 halogens	 i.e.	 greater	 the	 electronegativity	 of	 the	 halogen	
higher	will	be	the	antibacterial	activity.	

The	 deprotection	 of	 the	 acetylated	 nucleosides	 (3a‐j)	
results	 in	 increase	of	 the	antimicrobial	 activity.	Some	of	 these	
deprotected	 nucleosides	 (4a‐j)	 represented	 excellent	
antibacterial	 activity	 results	 against	 both	 gram	 positive	 and	
gram	 negative	 bacteria	 (Table	 3).	 The	 compounds	 (4a‐c)	
possess	5‐pyridyl	ring	are	more	effective	against	gram	negative	
strains	 than	 gram	 positive	 but	 the	 nucleosides	 (4f‐h)	 having	
halogen	 substituted	 5‐phenyl	 ring	 exhibited	 high	 potential	
against	 gram	 positive	 than	 gram	 negative	 bacteria.	 The	 most	



492	 Nadeem	and	Ashraf	/	European	Journal	of	Chemistry	3	(4)	(2012)	485‐492	
	
active	 deprotected	 nucleoside	 in	 this	 series	 is	 (4e)	 which	
possess	 trimethoxy	 substituted	5‐phenyl	 ring.	 The	 increase	 in	
antibacterial	 activity	 after	 deprotection	 is	 because	 of	 the	
presence	 of	 free	 hydroxyl	 groups	 which	 may	 involve	 in	
formation	 of	 hydrogen	 bonding	 with	 the	 polar	 receptor	
functionalities.	
	
4.	Conclusion	
	

Two	 different	 reaction	 routes	 are	 adopted	 for	 the	
preparation	 of	 4‐amino‐5‐substituted‐1,2,4‐triazole‐5‐thiones.	
The	 method	 in	 which	 absolute	 ethanol	 was	 used	 along	 with	
hydrazine	 furnished	 the	desired	products	with	excellent	 yield	
compared	 to	 the	 other	method.	 The	 glycosides	 of	 4‐amino‐5‐
substituted‐1,2,4‐triazole‐5‐thiones	 (2a‐j)	 are	 formed	 region‐
specifically	 as	 the	 reaction	 give	 only	 N‐glycosides	 not	 S‐
glycosides.	 The	 aminotriazloes	 (2a‐j)	 exhibited	 high	 anti‐
bacterial	activity	against	gram	positive	than	gram	negative	but	
the	protected	nucleosides	(3a‐j)	are	more	active	against	gram	
negative	 than	 gram	 positive	 bacteria.	 The	 deprotected	
nucleosides	 (4a‐j)	 in	 general	 showed	 high	 antimicrobial	
activity	 than	 4‐amino‐5‐substituted‐1,2,4‐triazole‐5‐thiones	
(2a‐j)	and	protected	nucleosides	(3a‐j).	The	hydrophobicity	of	
5‐aryl	 ring	 system	 and	 electronegativity	 of	 the	 halogens	 play	
important	role	in	antimicrobial	activity.		
	
Acknowledgement	
	

The	 authors	 are	 grateful	 to	 Dean,	 Riphah	 Institute	 of	
Pharmaceutical	Sciences	for	antimicrobial	studies.		
	
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