A mild and convenient synthesis of 1,2,3-triiodoarenes via consecutive iodination/diazotization/iodination strategy

Article abstract of DOI:10.1071/CH13324

A mild and convenient synthesis of 1,2,3-triiodoarenes has been developed. This method consists of two steps which can be performed on multigram scale with moderate to excellent yields. This report discloses a practical synthesis of 1,2,3-triiodoarenes and 1,2,3-trihaloarenes that is general in scope, operationally simple, scalable, and is easy to workup and to purify. We also report the first regioselective transmetalation reaction of 1,2,3-triiodoarenes to provide ortho-diiodoaryl derivatives, which are useful building blocks and indeed are hard to make by other means. CSIRO 2013.

Full text of DOI:10.1071/CH13324

CSIRO PUBLISHING
Aust. J. Chem.
Full Paper
http://dx.doi.org/10.1071/CH13324
A Mild and Convenient Synthesis of 1,2,3-Triiodoarenes via
Consecutive Iodination/Diazotization/Iodination Strategy
A C
,
A
B
Raed M. Al-Zoubi,
Hassan Abul Futouh, and Robert McDonald
A
Department of Chemistry, Jordan University of Science and Technology,
PO Box 3030, Irbid, 22110, Jordan.
B
Department of Chemistry, Gunning-Lemieux Chemistry Centre, University of Alberta,
Edmonton, Alberta, T6G2G2, Canada.
C
Corresponding author. Email: rmzoubi@just.edu.jo
A mild and convenient synthesis of 1,2,3-triiodoarenes has been developed. This method consists of two steps which can
be performed on multigram scale with moderate to excellent yields. This report discloses a practical synthesis of 1,2,3-
triiodoarenes and 1,2,3-trihaloarenes that is general in scope, operationally simple, scalable, and is easy to workup and to
purify. We also report the first regioselective transmetalation reaction of 1,2,3-triiodoarenes to provide ortho-diiodoaryl
derivatives, which are useful building blocks and indeed are hard to make by other means.
Manuscript received: 25 June 2013.
Manuscript accepted: 20 August 2013.
Published online: 25 September 2013.
Introduction
comprising an iodo substituent at the ortho-position instead of a
chloro substituent. Compound 2 was found to inhibit cyclooxy-
genase slightly more than diclofenac (it inhibits cyclooxygenase
at the enzyme level and also rat adjuvant arthritis in vivo).
Interestingly, the ortho-difluoro derivative was found to be
significantly less active than diclofenac. It was concluded that
the twist between the two rings is crucial for high activity. The
ortho-diiodo derivative, which is expected to have a larger twist
of the two rings, has not been reported. Moreover, diatrizoate (3)
is a water-soluble iodinated first generation X-ray contrast
agent, developed for general intravascular use.[8]
The most commonly used methods for the synthesis of 1,2,3-
triiodoarenes employ direct polyiodination of benzene sulfonic
acid and nitroarenes, developed by Mattern and Darby respec-
tively.[9] Each route has different limitations, which hamper
their use in routine laboratory applications.[9,10]
Due to our interest in the chemistry of 1,2,3-triiodoarene
compounds, a concise and efficient method to access these
compounds was needed. Although there exists a large number
of established iodination protocols, a practical one for accessing
these compounds is still unavailable. We report herein a conve-
nient and effective method for the synthesis of 1,2,3-triiodoar-
enes and 1,2,3-trihaloarenes that is rather general in scope and
gives good yields (45–88 %). The method is operationally
simple, scalable, and is easy to workup and to purify. We also
show for the first time that these compounds can easily undergo
highly regioselective transmetalation reactions to provide ortho-
diiodoaryl derivatives, which are useful building blocks and
indeed are hard to make by other means.
Aryl iodides are versatile and useful compounds in organic
chemistry. They are used for the synthesis of remarkable inter-
mediates in agricultural chemicals, pharmaceuticals, and also
used as contrast agents in medical applications.[1] Due to the
relatively weak nature of the C–I bond, it can be transformed
into a plethora of other important organic products, particularly
by using transition metal catalyzed reactions or by organo-
lithium or organomagnesium intermediates.[2] Although a broad
palette of synthetic protocols for iodination of aromatic com-
pounds is available,[3] only a few of them are devoted at the
ortho-position.[4] One approach relies on the use of relatively
expensive 1,2-diiodobenzene as ortho-iodophenyl surrogate to
provide ortho-iodoarenes.[5] While the halogenation of aromatic
compounds is one of the most widely studied reactions in the
literature,[6] a practical iodination approach to access ortho-
diiodoaryl derivatives has not been reported.
Ortho-diiodoaryl compounds are found in a number of
biologically active compounds. For instance, thyroxine 1 (T4,
pharmaceutically levothyroxine, Fig. 1), is a tyrosine-based
hormone produced by the thyroid gland and is responsible
for regulation of metabolism.[7] Additionally, 2-(2-chloro-6-
iodoanilino) phenylacetic acid (2) is a diclofenac derivative
O
OH
NH2
I
NH
O
I
I
O
I
N
N
I
I
I
H
H
Cl
OH
O
I
HO
ꢀO
O
O
3
1
2
Results and Discussion
Thyroxine, T4
(Thyroid hormone)
Diclofenac derivative
Diatrizoate
(X-ray contrast agent)
We initiated this project by looking for an efficient iodination
method. Despite the large number of reports on regioselec-
tive[11] and direct aromatic iodination,[6] the iodination of
(NSAID drug)
Fig. 1. Some biologically important iodoarenes in nature and in medicine.
Journal compilation Ó CSIRO 2013
www.publish.csiro.au/journals/ajc

B
R. M. Al-Zoubi, H. A. Futouh, and R. McDonald
activated aromatic derivatives like aniline and phenol remains
a challenging task providing mixtures of ortho and para
iodinated products.[6] However, the low electrophilicity of
iodine compared to other halogens such as chlorine and bro-
mine, and the formation of HI which may cause decomposition
of sensitive intermediates, make direct iodination the least
reactive aromatic halogenation reaction. To overcome these
limitations, direct iodinations are often performed either under
oxidative conditions or under Lewis acidic conditions to
remove the iodide ions by oxidation or by precipitation
respectively.[6] Oxidative conditions are harsh and indeed not
compatible with many functionalized and sensitive substrates.
While the iodination of aromatic compounds is one of the most
studied reactions, only a few reports using Lewis acids have
been evaluated.[6] The most common Lewis acids are silver and
mercuric salts in combination with I2 or with ICl. This is
understandable by the fact that silver and mercury can remove
iodide efficiently as AgI and HgI2.[12]
We decided to revisit these latter conditions with different
solvents using 4-bromoaniline as a model substrate (Table 1).
First, a combination of silver sulfate and iodine was utilized at
room temperature. A quick optimization of solvent revealed that
ethanol and 1,2-ethanediol were the best solvents for the desired
transformation (entries 4 and 5). All other solvents were found to
be unsuitable for this reaction (entries 1–3). Using ethanol with
Hg(OAc)2/I2 instead of Ag2SO4/I2 provided less than 10 % of
the desired product (entry 6).
silver reagents on iodination of 4-bromoaniline to further
establish the reaction conditions. AgNO3/I2 led to a similar
result as Ag2SO4/I2 (entry 8), while both AgCl/I2 and AgOAc/I2
provided the desired product in 25 and 37 % respectively
(entries 9 and 10). No iodination was observed with
N-iodosuccinimide (NIS) in EtOH (entry 11), while NIS in
acetonitrile provided product in 29 % yield (entry 12). Using the
more reactive reagent ICl provided the desired product in only
21 % (entry 13). Thus the best yields for iodination were
obtained by using 1.1 equivalent of Ag2SO4 (entry 14) or 2.2
equivalents of AgNO3 (entry 8) with 2.0 equivalents of I2. The
reaction under the former conditions also worked well on
multigram scale (entry 16).
We next evaluated the substrate scope for direct iodination of
anilines using the optimized reaction conditions (Scheme 1).
Different aniline derivatives were subjected to the optimized
reaction conditions to provide the desired iodinated products.
For instance, anilines bearing chloro or bromo substituents
provided the desired iodinated products (4, 5, 10, and 11) in
the best yields (Scheme 1), whereas those bearing electron-
withdrawing deactivating substituents, such as fluoro and nitro,
gave products 6 and 9 in only low yields. Electron-rich groups
containing lone pairs of electrons for conjugation enhance the
reactivity of ortho and para positions towards electrophilic
substitution reactions. However, the iodination of highly acti-
vated aromatic compounds, such as 4-anisidine, provided an
inseparable mixture of iodinated products (14). Neutral sub-
strates were also subjected to the same reaction conditions to
Using Hg(OAc)2/I2 in DCM instead of EtOH provided a
mixture of iodinated products in 35 % yield (entry 7). Using
ethanol as a solvent, we then examined the influence of other
I
I2 (2.0 equiv)
NH2
NH2
I
Ag2SO4 (1.1 equiv)
R
R
EtOH, 25ꢁC
Table 1. Effect of different iodinating agents in the direct iodination of
4-bromoanilineA
I
I
I
I
NH2
NH2
NH2
I
NH2
NH2
I
Conditions
25ꢁC
Br
I
Cl
I
F
Br
Br
4
4
7
, 74 %
I
5
, 72 %
I
6
b, 31 %
I
Entry
Solvent
Iodinating agent
t [h]
Yield [%]B
1
THF
Ag2SO4/I2
Ag2SO4/I2
Ag2SO4/I2
Ag2SO4/I2
Ag2SO4/I2
Hg(OAc)2/I2
Hg(OAc)2/I2
AgNO3/I2
AgCl/I2
12
12
12
12
12
14
12
12
15
15
12
12
12
12
12
12
0C
23D
12D
69
NH2
NH2
NH2
2
CH2Cl2
CH3CN
3
H C
3
I
I
I
I
O N
2
I
4
HOCH2CH2OH
EtOH
5
73
6
EtOH
9
35D
, 56 %,
I
8, 51 %
9
, 32 %
I
7
CH2Cl2
EtOH
I
8
70
NH2
NH2
Br
NH2
9
CH3CN
EtOH
25
10
11
12
13
14
15
16G
AgOAc/I2
NIS
37
0C
I
Cl
I
CH3
EtOH
CH3CN
EtOH
NIS
29
10c, 88 %
11d, 89 %
12e, 25 %
ICl
21
EtOH
Ag2SO4/IE2
Ag2SO4/IF2
Ag2SO4/IE2
72
I
I
I
EtOH
74
NH2
NH2
NH2
CH3
13, 28 %
EtOH
68
HO
AAll reactions were carried out using 7.9 mmol (1.0 equiv.) of aniline
starting material, 2 equiv. of iodinating agent, and were stirred at 258C for the
time specified.
I
MeO
I
Cl
O
14f, 0 %
15, 0 %
BIsolated yield.
CNo reaction was observed.
aYields are given for isolated compounds (reaction scale: 5.81 mmol).
bRecovered starting material (32 %). cStarting from 2-chloroaniline.
dStarting from 2-bromoaniline. eStarting from ortho-toludine.
fA non-separable mixture of iodinated products (71 %).
DMixture of mono and diiodinated products were isolated.
EAg2SO4 (1.1 equiv. of Ag).
F Ag2SO4 (1.5 equiv. of Ag).
G3 g scale (17.4 mmol).
Scheme 1. Direct iodination of aniline derivatives.a

Synthesis and Reactivity of 1,2,3-triiodoarenes
C
provide the desired iodinated products (7, 8, 12, and 13). A
substrate with a carboxylic acid group did not provide the
desired iodinated product (15).
positions of the iodo substituents. The molecular geometry
shows an intramolecular steric repulsion between the vicinal
iodines. This steric repulsion results in the reduction of the
endocyclic angle (CꢀCꢀC ¼ 117.98) instead of elongation of
the CꢀI bonds.[15]
With the desired iodinated aniline derivatives in hand, we
then subjected them to the most commonly used method for
preparing aromatic iodides, the Sandmeyer reaction,[13] to
provide the desired triiodo and trihaloarenes (Scheme 2).
The advantage of the Sandmeyer reaction over other
methods for direct electrophilic iodination of aromatic com-
pounds is the selective addition of an iodo substituent into
a specified position on the aromatic ring, whereas direct
iodination usually provides mixtures of regioisomers. The
process of diazotization-iodination in the ‘Sandmeyer reac-
tion’ is usually carried out with sodium nitrite in hydrochloric
or sulfuric acid at low temperatures, followed by a subsequent
reaction with iodine and KI, sometimes in the presence of
copper salts.[13] Other modified methods such as the use
of different alkyl nitrites, different iodinating agents, and
different solvents have also been reported.[14]
Using 4-bromo-2,6-diiodoaniline as a model substrate, a
sequential diazotization-iodination in one-pot provided the
triiodoarene product in low yield. Trying to overcome the
solubility issue of this reaction in water, the ammonium chloride
salt was prepared and isolated from a reaction between 4-bromo-
2,6-diiodoaniline and hydrochloric acid in diethyl ether at 08C.
The salt was then subjected to the same diazotization-iodination
reaction conditions. Surprisingly, the desired triiodoarene 16
was isolated as the sole product in 81 % yield. Different
diiodoaniline derivatives were subjected to these optimal reac-
tion conditions, giving the desired triiodoarene and trihaloarene
products in good to excellent yields (Scheme 2).
To demonstrate the utility of 1,2,3-triiodoarenes as useful
intermediates in organic synthesis, different synthetic transfor-
mations were performed. 1,2,3-Triiodoarenes 16 19 were
]
converted into ortho-diiodoarene derivatives by highly regio-
selective metal-halogen exchange reaction in good yields
(Scheme 3: 25–30).
Conclusion
We have developed a mild and practical method for the syn-
thesis of different 1,2,3-triiodoarenes and 1,2,3-trihaloarenes
from aniline derivatives. This method is general in scope,
operationally simple, scalable, and is easy to workup and to
purify. The constitution of these compounds was confirmed on
the basis of X-ray crystallographic analysis. We also report
the first regioselective transmetalation reaction of 1,2,3-
triiodoarenes to provide ortho-diiodoaryl derivatives, which
are useful building blocks and indeed are hard to make by other
I
F
I
117.97
The geometry of the triiodoarene products was supported by
X-ray crystallographic analysis of one of the products, 5-fluoro-
1,2,3-triiodobenzene (Fig. 2, 18),[15] which clearly indicates the
l
I
I
Fig. 2. ORTEP view of 5-fluoro-1,2,3-triiodobenzene (18). Thermal
NH2
I
I
I
1. HCl, diethylether, 0ꢁC
Gaussian ellipsoids at 20 % probability level.
R
R
2. NaNO2, KI, HCl, H2O
60 min, 0ꢁC–80ꢁC
I
I
i. t-BuLi (2.2 equiv),
THF, ꢀ78ꢁC, 1h.
I
I
E
I
I
I
I
ii. Eꢃ, THF, 24h
I
I
I
I
R
R
16–19
Br
I
Cl
I
F
I
I
I
H
CH3
H
I
16, 81 %
17, 88 %
18, 45 %
I
I
I
Cl
I
Cl
I
Br
I
I
I
Eꢃ ꢂ EtOH
25, 65 %
Eꢃ ꢂ CH3I
26, 47 %
Eꢃ ꢂ EtOH
27, 68 %
O2N
H3C
I
I
I
I
I
I
I
I
19, 59 %
20, 46 %
21, 26 %
H
H
I
TMS
I
I
I
H3C
I
I
I
Br
I
CH3
F
H3C
I
Eꢃ ꢂ TMSCl
30, 39 %b
Eꢃ ꢂ EtOH
29, 73 %
Eꢃ ꢂ EtOH
28, 71 %
I
Cl
X
24, X ꢂ I, 45 %
25, X ꢂ Cl, 0 %
aYields are given for isolated
compounds.
bRecovered starting material (55 %).
22, 66 %
23, 67 %
aYields are given for isolated compounds.
Scheme 3. Regioselective metal-halogen exchange reactions of 1,2,3-
triiodoarenes 16–19.
Scheme 2. Diazotization-iodination of iodinated aniline derivatives.a

D
R. M. Al-Zoubi, H. A. Futouh, and R. McDonald
means. With other iodo substituents, further elaboration can
easily be achieved.
4-Chloro-2-iodo-6-methylaniline (13)
The title compound was prepared using the general proce-
dure for halogenation of aniline derivatives and isolated in 28 %
yield as a white solid. Mp 58–608C. dH (400 MHz, CDCl3) d:
7.50 (d, 1H, J 1.9, CH), 7.02 (d, 1H, J 1.9, CH), 4.06 (s, 2H,
NH2), 2.20 (s, 3H, CH3). dC (100 MHz, CDCl3) d: 143.6, 135.5,
130.1, 123.3, 122.8, 83.6, 18.8. nmax(neat)/cmꢀ1 3511, 3395,
3120, 2915, 1682, 1154, 1321, 892. m/z (HR-MS EI) 265.9378;
[M-H]ꢀ requires 265.9312.
Experimental
General
All commercial reagents and chromatography solvents were
used as obtained unless otherwise stated. Anhydrous solvents
were distilled over appropriate drying agents before use. Ana-
lytical thin layer chromatography (TLC) was performed on
Merck silica gel 60 F254. Merck silica gel 60 (0.063–0.2 mm)
was used for column chromatography. Visualization of TLC
was accomplished with ultraviolet light (254 nm). NMR spectra
were recorded on a Bruker-Avance 400 MHz spectrometer. The
residual solvent protons (1H) or the solvent carbon peaks (13C)
were used as internal standards. 1H NMR data are presented as
follows: chemical shift in ppm (d) downfield from tetra-
methylsilane (multiplicity, integration, coupling constant). The
following abbreviations are used in reporting NMR data:
s, singlet; br s, broad singlet; d, doublet; t, triplet; q, quartet; dq,
doublet of quartets; dd, doublet of doublets; m, mutiplet. High
resolution mass spectra were recorded by Jordan University of
Science & Technology.
General Procedure for Diazotization of Aniline Derivatives
Concentrated HCl was added dropwise to a solution of iodinated
aniline derivative (1.4 mmol, 1.0 equiv.) in 15 mL diethyl ether
at 08C until no more precipitate formed. The aniline salt was then
filtered, washed with cold diethyl ether, and collected. A solu-
tion of NaNO2 (1.53 mmol, 1.1 equiv.) in water (1.0 mL) was
added dropwise to a mixture of aniline salt in water (3.5 mL) and
concentrated hydrochloric acid (1.5 mL) below 58C, and the
mixture was stirred for 10 min. A solution of potassium iodide
(2.1 mmol, 1.5 equiv.) in water (1.0 mL) was then added drop-
wise to the reaction mixture. The mixture was stirred for 15 min
without cooling, at 508C for 30 min and then followed by 45 min
at 808C. The mixture was then cooled to 08C, and a solution of
5 % aqueous sodium sulfite (30 mL) was added. The organic
layer was separated, and the aqueous layer was extracted with
diethyl ether (3 ꢁ 30 mL). The combined organic layers were
washed with brine, dried over Na2SO4, filtered, and concen-
trated. The residue was chromatographed on silica gel (hexane)
to yield the pure desired product.
General Procedure for Iodination of Aniline Derivatives
Aniline derivative (7.9 mmol, 1.0 equiv.), iodine (17.3 mmol,
2.2 equiv), and silver(I) sulfate (3.2 mmol, 1.1 equiv) were dis-
solved in ethanol (40 mL) and stirred for 24 h at room temper-
ature. The mixture was filtered over Celite 545 to remove AgI
precipitate. Water (200 mL) was added to the filtrate and then
the mixture was then extracted with ethyl acetate (3 ꢁ 50 mL).
The combined organic layers were washed with aqueous sodium
sulfite to remove excess iodine, brine, and then dried over
Na2SO4, filtered, and concentrated. The residue was chroma-
tographed on silica gel (hexane/ethyl acetate 7 : 1) to yield the
pure desired product.
5-Bromo-1,2,3-triiodobenzene (16)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 81 %
yield as a white solid. Mp 138–1408C. dH (400 MHz, CDCl3) d:
7.97 (s, 2H, CH). dC (100 MHz, CDCl3): 141.7, 140.2, 122.6,
106.7. nmax(neat)/cmꢀ1 2987, 1642, 1546, 1051, 860. m/z
(HR-MS EI) 533.6499; [M]þ requires 533.6474.
4-Fluoro-2,6-diiodoaniline (6)
The title compound was prepared using the general proce-
dure for halogenation of aniline derivatives and isolated in 31 %
yield as a white solid. Mp 67–698C. dH (400 MHz, CDCl3): 7.44
(d, 2H, J 7.4, CH), 4.46 (s, 2H, NH2). dC (100 MHz, CDCl3):
154.8, 152.3, 142.7, 125.6, 125.3, 78.9, 78.8. nmax(neat)/cmꢀ1
3377, 3258, 3037, 2957, 1616, 1584, 1419, 1004, 900. m/z
(HR-MS EI) 362.8434; [M-H]ꢀ requires 362.8417.
5-Chloro-1,2,3-triiodobenzene (17)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 88 %
yield as a white solid. Mp 118–1208C. dH (400 MHz, CDCl3):
7.86 (s, 2H, CH). dC (100 MHz, CDCl3): 138.3, 135.3, 119.2,
106.8. nmax(neat)/cmꢀ1 3025, 1633, 1492, 894. m/z (HR-MS EI)
489.6939; [M]þ requires 489.6979.
2-Chloro-4,6-diiodoaniline (10)
The title compound was prepared using the general proce-
dure for halogenation of aniline derivatives and isolated in 88 %
yield as a white solid. Mp 71–738C. dH (400 MHz, CDCl3): 7.79
(s, 1H, CH), 7.50 (s, 1H, CH), 4.56 (s, 2H, NH2). dC (100 MHz,
CDCl3): 144.4, 143.2, 137.2, 118.3, 83.8, 77.5. nmax(neat)/cmꢀ1
3416, 3387, 3055, 1652, 1167, 1121, 950. m/z (HR-MS EI)
377.8179; [M-H]ꢀ requires 377.8122.
5-Fluoro-1,2,3-triiodobenzene (18)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 45 %
yield as a white solid. Mp 127–1298C. dH (400 MHz, CDCl3) d:
7.62 (d, 2H, J ¼ 4.0 Hz). dC (100 MHz, CDCl3) d: 161.8, 159.3,
126.2, 125.9, 115.1, 105.5, 105.4. nmax(neat)/cmꢀ1 3065, 2941,
1596, 1435, 1187, 852. m/z (HR-MS EI) 473.7213; [M]þ
requires 473.7275.
2-Bromo-4,6-diiodoaniline (11)
The title compound was prepared using the general proce-
dure for halogenation of aniline derivatives and isolated in 89 %
yield as a white solid. Mp 65–678C. dH (400 MHz, CDCl3): 7.84
(s, 1H, CH), 7.67 (s, 1H, CH), 4.64 (s, 2H, NH2). dC (100 MHz,
CDCl3): 145.1, 143.9, 140.1, 107.6, 83.4, 77.9. nmax(neat)/cmꢀ1
3412, 3314, 2954, 1622, 1095, 930. m/z (HR-MS EI) 423.7640;
[MþH]ꢀ requires 423.7616.
1,2,3-Triiodo-5-methylbenzene (19)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 59 %
yield as a white solid. Mp 113–1158C. dH (400 MHz, CDCl3):
7.69 (s, 2H, CH), 2.17 (s, 3H, CH3). dC (100 MHz, CDCl3):
140.9, 139.1, 116.3, 106.3, 19.4. nmax(neat)/cmꢀ1 3149, 2985,

Synthesis and Reactivity of 1,2,3-triiodoarenes
E
1614, 1587, 1215, 1146, 840. m/z (HR-MS EI) 469.7594; [M]þ
requires 469.7525.
5-Chloro-1,3-diiodo-2-methylbenzene (26)
The title compound was prepared using the general proce-
dure for metal-halogen exchange reaction and isolated in 47 %
yield as a white solid. Mp 145–1478C. dH (400 MHz, CDCl3):
7.82 (s, 2H, CH), 2.72 (s, 3H, CH3). dC (100 MHz, CDCl3):
141.2, 138.3, 131.8, 97.8, 33.7. nmax(neat)/cmꢀ1 3148, 2975,
2846, 1634, 1573, 1243, 1147, 876. m/z (HR-MS EI) 377.8144;
[M]þ requires 377.8169.
1,2,3,5-Tetraiodobenzene (20)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 46 %
yield as a white solid. Mp 133–1358C. dH (400 MHz, CDCl3):
8.13 (s, 2H, CH). dC (100 MHz, CDCl3): 146.1, 121.0, 108.1,
94.9. nmax(neat)/cmꢀ1 2987, 1534, 1145, 1009, 873. m/z
(HR-MS EI) 581.6358; [M]þ requires 581.6335.
(2,6-Diiodo-4-methylphenyl)trimethylsilane (30)
The title compound was prepared using the general proce-
dure for Metal-Halogen Exchange reaction and isolated in 39 %
yield as a colourless oil. dH (400 MHz, CDCl3): 7.81 (s, 2H, CH),
2.18 (s, 3H, CH3), 0.64 (s, 9H, Si(CH3)3). dC (100 MHz, CDCl3):
141.8, 141.2, 136.9, 102.6, 19.1, 4.53. nmax(neat)/cmꢀ1 3201,
2918, 2894, 1687, 1548, 1423, 1250, 1146, 944. m/z (HR-MS EI)
415. 8913; [M]þ requires 415. 8954.
1-Chloro-2,3,5-triiodobenzene (22)
The title compound was prepared using the general proce-
dure for diazotization aniline derivatives and isolated in 66 %
yield as a white solid. Mp 112–1148C. dH (400 MHz, CDCl3):
8.07 (s, 1H, CH), 7.71 (s, 1H, CH). dC (100 MHz, CDCl3): 145.1,
139.6, 136.6, 112.6, 110.8, 94.2. nmax(neat)/cmꢀ1 3012, 2983,
1642, 1548, 1124, 863. m/z (HR-MS EI) 489.6935; [M]þ
requires 489.6979.
Supplementary Material
1H and 13C NMR, IR and HRMS data, experimental procedures
for new compounds, and X-ray crystallographic data for com-
pound 18 can be found on the Journal’s website.
1-Bromo-2,3,5-triiodobenzene (23)
The title compound was prepared using the general proce-
dure for diazotization of aniline derivatives and isolated in 67 %
yield as a white solid. Mp 113–1158C. dH (400 MHz, CDCl3):
8.10 (s, 1H, CH), 7.88 (s, 1H, CH). dC (100 MHz, CDCl3): 145.5,
139.7, 130.2, 115.3, 110.3, 94.5. nmax(neat)/cmꢀ1 3042, 2968,
1604, 1523, 1154, 760. m/z (HR-MS EI) 533.6423; [M]þ
requires 533.6474.
Acknowledgements
We are grateful to the Applied Scientific Research Fund (ASRF) of Jordan
and Jordan University of Science and Technology (JUST) for financial
support. We thank the department of chemistry at University of Alberta for
X-ray crystallographic analysis.
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