Novel synthesis of 2-Aminothiazoles via Fe(III)-Iodine-catalyzed Hantzsch-type condensation

Article abstract of DOI:10.1002/jhet.4166

A novel iron-iodine catalyzed one pot synthesis of 2-aminothiazoles from methyl aryl ketones and thiourea is demonstrated. This protocol can be considered as a catalyzed version of the classical Hantzsch aminothiazole synthesis as it enables the in situ generation of α-iodoketones in the reaction medium using catalytic amount of iodine leading to Hantzsch condensation with thiourea. The supply of iodine for multiple catalytic cycles is ensured by using catalytic amounts of iron as it enables iodide to iodine oxidation. The generality of this protocol is also well established in this manuscript by synthesizing a variety of 2-aminothiazoles from different ketones and thiourea.

Full text of DOI:10.1002/jhet.4166

COMMUNICATION
DOI: ((will be filled in by the editorial staff))
Novel Synthesis of 2-Aminothiazoles via Fe(III)-Iodine
Catalyzed Hantzsch Type Condensation
Sankuviruthiyil M Ujwaldev, [a] Nissy Ann Harry, [a] Mohan Neetha, [a] and Gopinathan
Anilkumar *[a] [b] [c]
[a]
School of Chemical Sciences
Mahatma Gandhi University
P D Hills P O, Kottayam, Kerala, India, 686560
anilgi1@yahoo.com
Advanced Molecular Materials Research Centre (AMMRC)
[b]
Mahatma Gandhi University,
P D Hills P O, Kottayam, Kerala, India, 686560
Institute for Integrated Programmes and Research in Basic Sciences (IIRBS)
[c]
Mahatma Gandhi University,
P D Hills P O, Kottayam, Kerala, India, 686560
Received: ((will be filled in by the editorial staff))
methodology which involves reaction of thioamides
Abstract. A Novel iron-iodine catalyzed one pot synthesis
with α-haloketones to afford aminothiazoles. It was
of 2-aminothiazoles from methyl aryl ketones and thiourea
is demonstrated. This protocol can be considered as a
catalyzed version of the classical Hantzsch aminothiazole
synthesis as it enables the in situ generation of α-
first reported in 1887 (Scheme 1a) and later
underwent many developments. The major
modification was the use of ketone along with
stoichiometric amounts of iodine instead of
haloketones to afford aminothiazoles on reaction with
thiourea i. e. Oxidative cyclocondenstion [14] (Scheme
1b). This protocol was superior over Scheme 1a,
since α-haloketones were less commercially available
and possess lachrymatory nature. Use of
stoichiometric amounts of iodine often resulted in the
formation of unwanted by-products leading to
complex separation procedures. Our group’s
continued interest in developing transition metal
catalyzed versions of classic name reactions [15] made
us investigate a similar scope in the case of Hantzsch
reaction also. By using a catalytic amount of iron and
iodine, we could develop a protocol that employs
acetophenone and thiourea as the starting materials to
afford 2-aminothiazoles (Scheme 1c). We propose
that via repeated iron-iodine-involved catalytic cycles,
in situ generation of α-iodoacetophenone from
acetophenone could take place in the reaction mixture
which would react with thiourea to afford the product.
The protocol is very useful towards the synthesis of a
variety of 2-aminothiazoles from 2-methylketones
and thiourea under much milder conditions.
iodoketones in the reaction medium using catalytic amount
of iodine leading to Hantzsch condensation with thiourea.
The supply of iodine for multiple catalytic cycles is ensured
by using catalytic amounts of iron as it enables iodide to
iodine oxidation. The generality of this protocol is also well
established in this manuscript by synthesizing a variety of
2-aminothiazoles from different ketones and thiourea.
Keywords: aminothiazole; catalysis ; Hantzsch reaction ;
iodine ; iron
1. Introduction
2-Aminothiazoles are very important heterocycles
known for their wide spectrum of biological activities.
Many drugs are available in the market nowadays
containing aminothiazole core including potent CNS
active agents. Some of the examples are Cefdinir
(Anti-biotic), [1] Famotidine (Histamine-2 blocker), [2]
[3]
Abafungin (Anti-microbial),
Fanetizole (Anti-
[4]
inflammatory),
Pramipexole (Treatment of
etc. The known methods for
[5]
Parkinson’s disease)
the synthesis of these molecules include i) from
acetophenone and thiourea mediated by strong
[6]
oxidizing agents
like Sulfuryl chloride, Sulfur
trioxide, Nitric acid, Sulfur, halogen [7] etc. ii) from α-
diazoketone and thiourea [8] iii) from primary amines
[9]
and halo-thiocyanatoalkenes iv) from alkynes and
[10]
thiourea
v) from α-nitro epoxides and thiourea [11]
[12]
vi) from vinyl azides with thiocyanate
etc.
[13]
Hantzsch condensation
is a well explored
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Table 1: Optimization studies
Yiel
d
Sl
Iron
Iodide
source
Tem Ti
p. me
(oC) (h)
No catalyst
.
Solvent
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
DME
(%)a,
(mol%) (mol%)
b
FeCl3.
I2
6H2O
(20
1
110
80
24
24
24
24
24
24
24
24
24
24
24
28
18
(20
mol%)
mol%)
FeCl3.
I2
6H2O
(20
2
3
(20
mol%)
mol%)
Scheme 1. Scheme 1: a) Classical Hantzsch condensation
between α-halo ketone and thioamide; b) Oxidative
cyclocondensation using stoichiometric amounts of iodine
c) Our modification leading to catalytic version of
Hantzsch condensation.
FeCl3.
I2
6H2O
(20
trace
s
130
110
110
110
110
110
110
110
110
(20
mol%)
mol%)
FeCl3.
KI
6H2O
4
(30
24
(30
Recently many green approaches were emerged in
the area of Hantzsch reaction to afford 2-
aminothiazoles. [16] Our methodology will be a new
addition to these protocols as it uses environmentally
benign PEG-400 as the solvent along with iron/iodine
catalytic system.
mol%)
mol%)
Fe(NO3)
I2
3. 9H2O
(20
trace
s
5
(20
mol%)
mol%)
FeCl3.
I2
6H2O
(20
6
25
2. Result and Discussion
(20
mol%)
mol%)
The optimization studies were began with a trial
reaction involving acetophenone, 1a (0.5 mmol) and
thiourea 2a (0.6 mmol) as the substrates. Ferric
chloride hexahydrate and iodine were used as the
FeCl3.
I2
6H2O
(20
trace
s
7
THF
(20
mol%)
mol%)
o
catalysts. All the reagents were stirred at 110 C in a
FeCl3.
I2
sealed tube using CH3CN as the solvent (Scheme 2).
The progress of the reaction was monitored using
TLC and the reaction mixture was quenched after 24
hours and extracted using ethyl acetate. The residue
obtained after concentration of the solvent was
purified using column chromatography (Hexane-
EtOAc) to furnish the desired 4-phenylthiazol-2-
amine in 28 % yield.
6H2O
(20
8
DMF
30
(20
mol%)
mol%)
FeCl3.
I2
6H2O
(20
trace
s
9
DMSO
tBuOH
EtOH
(20
mol%)
mol%)
FeCl3.
I2
6H2O
(20
10
11
38
(20
mol%)
mol%)
FeCl3.
I2
6H2O
(20
trace
s
(20
mol%)
Scheme 2: Iron catalyzed Hantzsch-type reaction between
mol%)
acetophenone and thiourea.
FeCl3.
I2
6H2O
(20
trace
s
12
13
Toluene
NMP
110
110
24
24
(20
mol%)
mol%)
Once the trial reaction was found proceeding in the
desired way, further studies were carried out by
varying the iron salt, iodine source, solvent, time,
temperature and the catalyst loading (Table 1).
FeCl3.
6H2O
(20
I2
(20
mol%)
28
2
This article is protected by copyright. All rights reserved.

o
b
Solvent, 80-110 C, 19-30 h; Isolated yield. nd= not
detected.
mol%)
FeCl3.
6H2O
(20
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(50
mol%)
FeCl3.
6H2O
(20
I2
(20
mol%)
PEG-
400
14
15
16
17
18
19
20
21
22
23
110
110
110
110
110
110
110
110
110
110
24
24
24
24
24
24
24
24
19
30
41
58
48
38
38
The first parameter we modified in comparison to
the trial reaction (Entry 1) was the temperature by
keeping all the other parameters the same. A decrease
or an increase in the temperature was found to cause
the yield to decrease or the amount of product
become traces (Entry 2&3). The use of
Fe(NO3)3.9H2O instead of FeCl3.6H2O or KI instead
of I2 also didn’t improve the yields (Entry 4&5).
Influence of different solvents in the reaction was
then examined. Solvents including tetrahydrofuran,
dimethylsulfoxide and ethanol were ineffective
(Entry 7, 9&11). Similar was the result in the case of
toluene (Entry 12). NMP gave only 28% of the yield
I2
(30
mol%)
PEG-
400
I2
(30
mol%)
CH3CN
DMF
I2
(30
mol%)
t
while BuOH and PEG-400 gave improved yields of
38% and 41% respectively (Entry 13, 10&14). Upon
increasing the quantities of both FeCl3.6H2O and I2
from 20 mol% to 30 mol%, the yields got increased.
In the case of acetonitrile, the yield was improved to
48% (Entry 16). Similarly PEG-400 has furnished
58% of the product and was found to be the best
solvent among the all (Entry 15). Thus we have
chosen PEG-400 as the solvent for the subsequent
studies. A decrease in the duration of the reaction
from 24 hours to 19 hours resulted in lowering of the
yield (Entry 22). However, an increase of reaction
time did not make any impact on the yield (Entry 23).
A change in the catalytic loading from 30 mol% to 50
mol% resulted in the decrease of the yield (Entry 20).
We also changed the [Fe]:I2 ratio to 1:1.5, which
offered a reduced yield of 40% (Entry 21). The
catalytic activity of a ferrous salt was also tested to
afford 42% of the product (Entry 25). When the
reaction was carried out in the absence of iron the
yield was only 35% (Entry 26). The use of iron as
the sole catalyst only delivered traces of the product
(Entry 27). From all these results, we have
concluded Entry 15 as the optimum condition and
proceeded with the substrate scope studies.
The generality of this protocol was well studied
later with a variety of ketones and thiourea. Electron
withdrawing as well as electron donating groups were
well tolerated under the reaction conditions (Scheme
3). Electronic nature of the substituents on the
arylketones did not make any direct correlation with
the yields. Among the halo ketones, 4-
chloroacetophenone offered the highest yield
(Scheme 3, 3da) whereas 4-iodoacetophenone
afforded the lowest (Scheme 3, 3ga). In the case of
heterocyclic ketone, the yield was very low (Scheme
3, 3ma). Cyclopentanone furnished 5,6-dihydro-4H-
cyclopenta[d]thiazol-2-amine as the product, albeit in
very low amounts (Scheme 3, 3na). N-
Phenylthiourea (Scheme 3, 3ab) has provided only
16% of the product, presumably due to steric effects.
I2
(30
mol%)
tBuOH
H2O
I2
(30
mol%)
trace
s
I2
(50
mol%)
PEG-
400
43
40
43
56
I2
(30
mol%)
PEG-
400
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3.
6H2O
(30
mol%)
FeCl3
Anhydro
us
I2
(30
mol%)
PEG-
400
I2
(30
mol%)
PEG-
400
I2
(30
mol%)
PEG-
400
24
110
24
53
(30
mol%)
Fe(OTf)
I2
(30
mol%)
PEG-
400
2
25
26
110
110
24
24
42
35
(30
mol%)
I2
(30
mol%)
PEG-
400
-
FeCl3.
6H2O
(30
PEG-
400
trace
s
27
28
-
110
110
24
24
mol%)
PEG-
400
-
-
nd
a Reaction Conditions: 1a (0.5 mmol), 2a (0.6 mmol), Fe
catalyst (20-50 mol%), Iodide source (20-50 mol%),
3
This article is protected by copyright. All rights reserved.

We have developed, a catalyzed version of
Hantzsch-type reaction towards the synthesis of 2-
aminothiazoles from methyl aryl ketones and thiourea.
The protocol employs a catalytic system composed of
FeCl3.6H2O and iodine in environmentally benign
PEG-400 as the solvent. The major advantages of this
methodology over the existing protocols are that it
avoids α-prefunctionalization of ketones, use of
strong oxidizing agents and only require catalytic
amounts of iodine.
4. Experimental Section
4.1. General Remarks
Ferric chloride hexahydrate, Thiourea and Potassium
iodide were purchased from Sigma Aldrich, Germany. The
Iodine resublimed, Toluene, NMP and t-Butanol were
provided by SRL chemicals, India. Anhydrous Ferric
chloride and ferric nitrate nonahydrate were purchased
from Merck Specialities Pvt. Ltd. India. Methanol, DMF
and acetonitrile were the products of Sigma Aldrich. Other
solvents including PEG-400 and Ethanol were respectively
purchased from Spectrochem, India and Hayman. The
ketones used were manufactured by Sigma Aldrich, Alfa
Aesar and SRL, India. Solvents used for column
chromatography were purchased from Thermofischer
scientific and distilled before use. The NMR spectra were
recorded using a Bruker-500 MHz NMR spectrometer
instrument. The chemical shift values were reported in
‘ppm’ relative to TMS (1H) and CDCl3 (13C) as internal
standards. Coupling constants (J) were stated in Hertz (Hz).
The GC-MS and HRMS were recorded respectively on
Agilent and XEVO G2 Q-TOF (Waters) mass
spectrometers. Column chromatography was carried out
using 100-200 mesh silica gel from SRL chemicals. Thin
Layer Chromatography was carried out using Merck
SilicaGel 60/UV254 plates and the spots were detected
using either UV fluorescence or by Iodine chamber.
a
Reaction Conditions: 1 (0.5 mmol), 2 (0.6 mmol),
FeCl3.6H2O (30 mol%), iodine (30 mol%), PEG-400, 110
oC, 24 h; b Isolated yields.
Scheme 3: Substrate scope studies
Finally we propose
a mechanism for this
transformation. It initiates with the in situ generation
of the α-iodoketones, 4 from the methyl ketones,
which then undergoes Hantzsch type condensation
with thiourea to afford the product (4 to 3). There are
two iodide ions being liberated during each catalytic
cycle, which are oxidized back to the molecular
iodine by Fe3+. The Fe2+ ion formed during this step is
converted to the active Fe3+ ion by the oxygen present
in the aerobic atmosphere (Scheme 4).
4.2. General procedure for the Synthesis of 2-Aminothiazoles
An oven dried sealed tube containing a magnetic stirring
bar was charged with the ketone (0.50 mmol), thiourea
(0.60 mmol), FeCl3.6H2O (30 mol%), Iodine (30 mol%)
and PEG-400 (1 mL). The tube was tightly closed and the
contents were stirred at 110 oC for 24h in an oil bath. Upon
completion, the reaction mixture was extracted with
EtOAc (15 mLx3 times). The extract was dried over dry
Na2SO4 and the solvent was removed in vaccuo using a
rotatory evaporator. The obtained residue was later
purified by column chromatography (Silica 60-120 mesh)
using hexane-EtOAc mixture.
4.3. Compound Characterization Data
4-Phenylthiazol-2-amine (3aa);[17] Chemical Formula:
C9H8N2S; Appearance: White Solid; Yield: 51 mg (58%);
o
MP: 150-152 C (lit. 151–153 oC)[17]; FT-IR (neat): 3433,
3248, 3153, 3113, 2921, 1689, 1596, 1515, 1329, 1038,
1
1022, H NMR (CDCl3, 400 MHz) δ 7.77 (d, J = 7.6 Hz,
2H), 7.38 (t, J = 8.0 Hz, 2H), 7.29 (t, J = 8.0 Hz, 1H), 6.71
(s, 1H), 5.30 (s, 2H); 13C NMR (CDCl3, 100 MHz) δ
167.5, 151.3. 134.7, 128.6, 127.8, 126.0, 102.8; GC-MS
(EI): m/z 176 (M+).
Scheme 4: The proposed mechanism
4-(p-Tolyl)thiazol-2-amine (3ba);[18] Chemical Formula:
C10H10N2S; Appearance: WhiteoSolid; Yield: 40 mg (42%);
o
MP: 128-130 C (lit. 124-126 C)[18]; FT-IR (neat): 3452,
3. Conclusion
3297, 3117, 2757, 1634, 1537, 1331, 1035, 1H NMR
(CDCl3, 500 MHz) δ 7.67 (d, J = 8.0 Hz, 2H), 7.19 (d, J =
8.0 Hz, 2H), 6.67 (s, 1H), 5.02 (s, 2H), 2.36 (s, 3H); 13C
4
This article is protected by copyright. All rights reserved.

NMR (CDCl3, 125 MHz) δ 167.2, 151.6. 137.7, 132.2,
129.4, 126.1, 102.3, 21.4; GC-MS (EI): m/z 190 (M+).
4-(4-Nitrophenyl)thiazol-2-amine (3ka);[17] Chemical
Formula: C9H7N3O2S; Appearance: Yellow powder; Yield:
40 mg (36 %); MP: 284-286 oC (lit. 285-286 oC)[17]; FT-IR
(neat): 3394, 3302, 3145, 3114, 1638, 1592, 1536, 1410,
1317, 1036, 1H NMR (DMSO-d6, 400 MHz) δ 8.23 (d, J =
8.0 Hz, 2H), 8.04 (d, J = 8.0 Hz, 2H), 7.40 (s, 1H), 7.25 (s,
2H); 13C NMR (DMSO-d6, 100 MHz) δ 168.6, 147.6,
146.0, 140.7, 126.3, 124.0, 106.6; GC-MS (EI): m/z 222
(M+H+).
4-(m-Tolyl)thiazol-2-amine (3ca);[17] Chemical Formula:
C10H10N2S; oAppearance: White Solid; Yield: 39 mg (41%);
o
MP: 84-86 C (lit. 88-91 C)[17]; H NMR (DMSO-d6, 500
MHz) δ 8.71 (bs, 2H), 7.55 (s, 1H), 7.51 (d, J = 10.0 Hz,
1H), 7.29 (t, J = 7.5 Hz, 1H), 7.17 (d, J = 7.5 Hz, 1H), 7.13
(s, 1H), 2.29 (s, 3H); 13C NMR (DMSO-d6, 125 MHz) δ
169.2, 139.6, 137.4, 128.9, 128.6, 128.0, 125.3, 121.9,
101.3, 20.1; GC-MS (EI): m/z 190 (M+).
4-(4-(Methylsulfonyl)phenyl)thiazol-2-amine
(3la);[21]
Chemical Formula: C10H10N2O2S2; Appearanoce: White
powder; Yield: 65 mg (51 %); MP: 225-227 C; FT-IR
(neat): 3417, 3278, 3108, 1646, 1532, 1280, 1035, 1H
NMR (DMSO-d6, 400 MHz) δ 8.04 (d, J = 8.0 Hz, 2H),
7.91 (d, J = 8.0 Hz, 2H), 7.30 (s, 1H), 7.18 (s, 2H), 3.22 (s,
3H); 13C NMR (DMSO-d6, 100 MHz) δ 168.5, 148.2,
139.4, 138.8, 127.4, 126.0, 105.2, 43.6; MS-MS (EI): m/z
255 (M+H+).
4-(4-Chlorophenyl)thiazol-2-amine (3da);[17] Chemical
Formula: C9H7ClN2S; Appearance: White Solid; Yield: 64
o
o
mg (61%); MP: 165-167 C (lit. 161-162 C)[17]; FT-IR
(neat): 3435, 3279, 3108, 2757, 1631, 1532, 1327, 1036,
1H NMR (CDCl3, 500 MHz) δ 7.71 (d, J = 8.5 Hz, 2H),
7.34 (d, J = 10.0 Hz, 2H), 6.71 (s, 1H), 5.05 (s, 2H); 13C
NMR (CDCl3, 125 MHz) δ 167.4, 150.4, 133.6, 133.3,
128.9, 127.4, 103.4; GC-MS (EI): m/z 210 (M+).
4-(Furan-2-yl)thiazol-2-amine
(3ma);[22]
Chemical
4-(3-Chlorophenyl)thiazol-2-amine (3ea);[18] Chemical
Formula: C7H6N2OS; Appearance: Whitoe Solid; 1Yield: 20
o
mg (24%); MP: 112-114 C (lit. 115 C) [23]; H NMR
Formula: C9H7ClN2S; Appearance: White Solid; Yield: 58
o
o
mg (55 %); MP: 128-130 C (lit. 126-128 C)[18]; FT-IR
(neat): 3310, 3127, 1632, 1517, 1337, 1050, 1H NMR
(CDCl3, 500 MHz) δ 7.69 (s, 1H), 7.56 (d, J = 7.5 Hz, 1H),
7.23-7.17 (m, 2H), 6.66 (s, 1H), 5.20 (s, 2H); 13C NMR
(CDCl3, 125 MHz) δ 167.6, 150.0, 136.5, 134.7, 130.0,
127.8, 126.3, 124.1, 104.0; GC-MS (EI): m/z 210 (M+).
(CDCl3, 500 MHz) δ 7.39 (s, 1H), 6.69 (s, 1H), 6.62 (d, J
= 3.5 Hz, 1H), 6.44 (m, 1H), 5.03 (s, 2H); 13C NMR
(CDCl3, 125 MHz) δ 167.6, 150.4, 143.0, 142.0, 111.5,
106.5, 102.5; GC-MS (EI): m/z 166 (M+).
N,4-Diphenylthiazol-2-amine
(3ab);[24]
Chemical
Formula: C15H12N2S; Appearance: Slightly yellow Solid;
Yield: 20 mg (16 %); MP: 138-140 oC (lit. 133-135 oC)[23]
;
4-(2,4-Dichlorophenyl)thiazol-2-amine
(3fa);[19]
1H NMR (CDCl3, 500 MHz) δ 7.86 (d, J = 10.0 Hz, 2H),
7.42-7.30 (m, 8H), 7.08 (t, J = 7.0 Hz, 2H), 6.84 (s, 1H);
13C NMR (CDCl3, 125 MHz) δ 164.5, 151.5, 140.4, 134.7,
129.6, 128.8, 128.0, 126.2, 123.1, 118.3, 102.0; GC-MS
(EI): m/z 252 (M+).
Chemical Formula: C9H6Cl2N2S; Appearance: White
o
Solid; Yield: 61 mg (50%); MP: 157-159 C (lit. 161-163
oC)[19];1FT-IR (neat): 3451, 3275, 3107, 1630, 1536, 1335,
1025, H NMR (CDCl3, 500 MHz) δ 7.81 (d, J = 10.0 Hz,
1H), 7.45 (d, J = 2.0 Hz, 1H), 7.27 (dd, J1 = 8.5 Hz, J2 =
2.0 Hz, 1H), 7.08 (s, 1H), 5.02 (s, 2H) 13C NMR (CDCl3,
125 MHz) δ 166.2, 146.6, 133.7, 132.5, 132.2, 132.0,
130.3, 127.3, 108.8; GC-MS (EI): m/z 244 (M+).
Acknowledgements
4-(4-Iodophenyl)thiazol-2-amine (3ga);[18] Chemical
SMU and NAH thank the University Grants Commission (UGC-
New Delhi), India and the Council of Scientific and Industrial
Research (CSIR-New Delhi), India for Junior Research
Fellowships respectively. GA and NM thank the Kerala State
Council for Science Technology and Environment (KSCSTE),
Formula: C9H7IN2S; Appearance: Pale Yellow Solid;
Yield: 73 mg (48 %); MP: 167-169 oC (lit. 176-177 oC)[18]
;
FT-IR (neat): 3420, 3279, 3107, 1627, 1530, 1326, 1034,
1H NMR (CDCl3, 500 MHz) δ 7.70 (d, J = 8.5 Hz, 2H),
7.52 (d, J = 8.5 Hz, 2H), 6.74 (s, 1H), 5.01 (s, 2H); 13C
NMR (CDCl3, 125 MHz) δ 167.4, 150.4, 137.8, 134.2,
127.9, 103.6, 93.3; GC-MS (EI): m/z 302 (M+).
Trivandrum, India for
a
research grant (Order No.
341/2013/KSCSTE dated 15.03.2013) and a research fellowship
respectively. The authors are also thankful to EVONIK
Industries, Germany for financial support (ECRP 2016 dated
6.10.2016). We also thank the Sophisticated Analytical
Instrument Facility (SAIF) Mahatma Gandhi University,
Kottayam for MS-MS analysis.
4-(4-Bromophenyl)thiazol-2-amine (3ha);[18] Chemical
Formula: C9H7BrN2S; Appearance: Pale Yellow Solid;
o
o
Yield: 61 mg (48%); MP: 184-186 C (lit. 179-181 C)[18]
;
FT-IR (neat): 3426, 3279, 3109, 2757, 1634, 1531, 1334,
1
1035, H NMR (CDCl3, 500 MHz) δ 7.65 (d, J = 8.5 Hz,
2H), 7.49 (d, J = 8.0 Hz, 2H), 6.73 (s, 1H), 5.02 (s, 2H) 13
C
References
NMR (CDCl3, 125 MHz) δ 167.4, 150.4, 133.8, 131.8,
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o
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COMMUNICATION
Novel Synthesis of 2-Aminothiazoles via Fe(III)-
Iodine Catalyzed Hantzsch Type Condensation
J. Heterocyclic Chem. Year, Volume, Page – Page
Sankuviruthiyil M Ujwaldev, Nissy Ann Harry,
Mohan Neetha and Gopinathan Anilkumar*
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