On the reaction of 4-substituted trimethyltin aromatics with perchlorylfluoride

Article abstract of DOI:10.1016/j.jorganchem.2006.04.023

To evaluate the suitability of [¹⁸F]perchorylfluoride [¹⁸F]FClO₃ as an electrophilic fluorination agent for the preparation of radiopharmaceuticals, the reactivity non-radioactive FClO₃ towards 4-substituted trimethyltin aromatic compounds was studied. Contrary to the expectation, an electrophilic fluorination of the aromatic nucleus did not occur. The reaction of perchlorylfluoride with aromatic trimethylstannyl compounds resulted in the formation of trimethyltin fluoride and the respective destannylated aromatics in variable yields.

Full text of DOI:10.1016/j.jorganchem.2006.04.023

Journal of Organometallic Chemistry 691 (2006) 3737–3742
www.elsevier.com/locate/jorganchem
On the reaction of 4-substituted trimethyltin aromatics
with perchlorylfluoride
*
Achim Hiller , Jo¨rg T. Patt, Jo¨rg Steinbach
Institute of Interdisciplinary Isotope Research, Radiopharmacy, Permoserstrasse 15, D-04318 Leipzig, Germany
Received 5 January 2006; received in revised form 13 April 2006; accepted 20 April 2006
Available online 13 May 2006
Abstract
To evaluate the suitability of [18F]perchorylfluoride [18F]FClO3 as an electrophilic fluorination agent for the preparation of radiophar-
maceuticals, the reactivity non-radioactive FClO3 towards 4-substituted trimethyltin aromatic compounds was studied. Contrary to the
expectation, an electrophilic fluorination of the aromatic nucleus did not occur. The reaction of perchlorylfluoride with aromatic tri-
methylstannyl compounds resulted in the formation of trimethyltin fluoride and the respective destannylated aromatics in variable yields.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Aryl stannanes; Perchlorylfluoride; Fluorination; Electrophilic substitution
1. Introduction
two major disadvantages: (1) The radiochemical yield is
ab initio limited to 50%. (2) The radiotracer is diluted by
high amounts of isotopic carrier compound 19F (carrier
added, c.a.). The importance of n.c.a. (no carrier added)
18F-labelled EFAs is based on the need for radiolabelling
nucleophilic moieties of molecules.
Perchlorylfluoride (FClO3) is a mild and selective gas-
eous EFA [6,7], which has been previously applied for fluo-
rination of various organic substances [8,9]. It was later
replaced by more reactive and more easily to handle EFAs
such as acetyl hypofluorite (AcOF) and Selectfluorꢁ [10].
For the synthesis of radiofluorinated EFAs, [18F]FClO3
was identified as the only substance within the scope of
our search, which can be generated in principle on an
n.c.a. level starting from [18F]fluoride [11]. [18F]fluoride is
produced in a cyclotron by proton irradiation of 18O-
enriched water and is obtained as aqueous solution with
high specific activity.
Trialkyltin substituted aromatic compounds are versa-
tile precursors for a variety of electrophilic substitution
reactions in particular for radiochemical syntheses. The
destannylation procedure has been used as a routine
method for many years to label specific molecules with
radioactive nuclides such as 123/131I, very recently summa-
rized in [1], 18F [2] and 211At [3]. Numerous precursors
are commercially available as trimethyltin or tributyltin
aromatics for such applications. Due to their high regiose-
lectivity, (radio)fluorodemetallation reactions are a very
efficient method to obtain fluorinated substances and 18F
labelled radioligands in good (radiochemical) yields [4],
for instance to synthesize 6-[18F]fluoro-L-DOPA [5].
Tracer compounds radiolabelled with the positron emit-
ter fluorine-18 play a pivotal role in functional molecular
imaging with positron emission tomography (PET) and
thus, 18F labelled compounds are important for non inva-
sive medical diagnostics and biomedical research with
PET. Radiolabelling methods starting with [18F]F2 and
the derived electrophilic fluorinating agents (EFAs) have
Ehrenkaufer and MacGregor [12] reported the synthesis
of 18F labelled aryl fluorides by the reaction of substituted
aryl lithiums with [18F]FClO3, the latter obtained however
from [18F]F2 with KClO3. First experiments in our labora-
tory to synthesize [18F]FClO3 starting from n.c.a. [18F]fluo-
ride were successful. [18F]FClO3 therefore should be a
potential candidate for an n.c.a. [18F]EFA. Coenen and
*
Corresponding author. Tel.: +49 341 235 2667; fax: +49 341 235 2731.
E-mail address: hiller@iif-leipzig.de (A. Hiller).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.04.023

3738
A. Hiller et al. / Journal of Organometallic Chemistry 691 (2006) 3737–3742
Moerlein [2] investigated the reactions of 18F labelled fluo-
rine and acetyl hypofluorite based on [18F]F2 (see above)
with a series of 4-substituted trimethyltin aromatics and
found this approach to be a promising preparative radiola-
belling method. This encouraged us to study the reactivity
of non-radioactive FClO3 on 4-substituted aromatic
trimethyltin compounds (1) for possible radiochemical
applications to prepare n.c.a. 18F labelled radiotracers.
Compounds 1, which comprise both electron deficient
and electron rich aromatic systems (see Table 1) were used
as model substrates expecting an SnMe3 for F exchange
(Scheme 1) and an increasing sensitivity to an electrophilic
attack in this direction. For comparison, trimethyl-naph-
thalen-1-yl-stannane (2), naphthalen-1-yl-lithium (3), and
sodium diethyl malonate (4a, see Scheme 2) were included
in this study.
Scheme 1.
Scheme 2.
n-BuLi in THF and trimethyltin chloride and the Pd-cata-
lyzed reaction of the corresponding iodine derivative with
hexamethyltin afforded 1b in good yields.
2. Results and discussion
All experiments were performed in micro scale with the
main goal to identify fluorinated products.
All trimethyltin aromatic compounds were characterized
by H NMR spectra.
1
2.1. Preparation of aromatic trimethyltin compounds
2.2. Reactions with perchlorylfluoride
The precursor compounds were prepared as shown in
Table 1 mainly referring to procedures reported in the lit-
erature. The reaction of an aromatic iodine compound with
hexamethyl-distannane (Sn2Me6) in the presence of tetra-
kis(triphenylphosphine)palladium(0) [Pd(PPh3)4] as cata-
lyst proved to be the best synthetic approach for the
trimethyltin precursors in most cases. Compound 1b is
cited without detailed description [13b]. Both the reaction
of (4-bromo-phenyl)-carbamic acid tert-butyl ester with
FClO3 was obtained by the reaction of KClO4 with flu-
orosulfonic acid at elevated temperature [9]. Two methods
for the reaction of the trimethyltin compound with FClO3
were used. Method A: addition of FClO3 at about À60 ꢂC
followed by gradual warming to 60 ꢂC in a closed vial
(‘‘closed system’’), method B: introduction of FClO3 at
about 0 ꢂC, further reaction at room temperature and at
about 60 ꢂC in an open vessel (‘‘open conditions’’). The
reactions were monitored at various temperatures by
Table 1
Synthesis scheme of 4-substituted aromatic trimethyltin compounds and trimethyl-naphthalen-1-yl-stannane (2)
X
Sn(CH3)3
R
R
Entry
Starting compound
Method
Separation/purification
Yield (%)
70
Reference
[13a]
X
R
1a
1b
1c
Iodo
NO2
A
Recryst., CC
PE/EtOAc 3:1
Bromo
Iodo
NHBoc
OCH3
C
B
CC PE/EtOAc 10:1
CC PE/DEE 5:1
81
81
–
–
Bromo
Iodo
C
B
CC PE/DEE 3:1
CC PE/EtOAc 10:1
70
85
[13c, modified]
[13d]
1d
1e
2
Bromo
Bromo
Bromo
NH2
B
CC PE/EtOAc 4:1
CC PE/EtOAc 10:1
Crude product
46a
42a
88b
[13e, modified]
[13f]
N(CH3)2
Naphthyl
D
C
[13g, modified]; [14]
Method. A: Sn2Me6; p-allyl PdCl2; B: Sn2Me6, [Pd(PPh3)4]; C: n-BuLi, Me3SnCl; D: Li, Me3SnCl CC: column chromatography silica gel 60; PE: petroleum
ether; EtOAc: ethyl acetate; DEE: diethyl ether.
a
Tends to decompose (destannylate) upon column chromatography complicating the separation of pure product.
Contains ꢀ8% naphthalene judged by 1H NMR analysis, TLC: not distinguishable.
b

A. Hiller et al. / Journal of Organometallic Chemistry 691 (2006) 3737–3742
3739
TLC. For most reactions anhydrous THF was used as sol-
vent [9]. All reactions with compounds 1a–e, 2 were con-
ducted several times showing good reproducibility.
(4-fluoro-phenyl)-carbamic acid tert-butyl ester could not
be detected in the product mixture. FClO3 did not react
with 1b, 1c in dichloromethane and petroleum ether as
solvent.
2.2.1. Reaction of sodium diethyl malonate (4a) and
naphthalen-1-yl-lithium (3) with FClO3
Perchlorylfluoride reacts with 1b, 1c by cleavage of the
SnMe3 group but with fluorinating the functional group
rather than the aromatic ring (Scheme 3). The formation
of the C–F bond is apparently prevented by the low elec-
trophilic power of FClO3 and the only less polarized C–
Sn bond due to the probably weak ÀI, +M effect of the
SnMe3 group [17]. Contrary to trimethyltin aromatics,
ortho-lithiated anisole and phenyl-carbamic acid tert-butyl
ester are converted into 2-fluoro derivatives in moderate
yield [12]. The formation of a stable delocalized anion is
supposed to promote the reaction of organolithium
reagents with FClO3 [15,18] but this mechanism does not
explain some successful fluorinations [8]. For comparison,
it was also not possible to fluorinate 1-(4-tributylstanna-
nyl-phenyl)-1H-pyrazole, a non-deactivated aromatic sys-
tem [21]. The behaviour of FClO3 significantly differs
from those of the more reactive [18F]AcOF [2] where the
formation of 4-fluoro compounds is the main reaction.
For the formation of 5a, 7a, 8a from FClO3 and 1a–c a
hydrogen atom must be abstracted, presumably from the
solvent (THF). We did not find aromatic perchloryl com-
pounds available from FClO3 and aromatics in the pres-
ence of aluminium chloride as Friedel-Crafts catalyst
[19,20], even though Sn(IV) may act as a weak Lewis acid.
The by-products bis-[4-(tert-butoxycarbonyl-amino)-
phenyl]-dimethyl-stannane (7b) and bis-(4-methoxy-phe-
nyl)-dimethyl-stannane (8b) (given in square bracket in
Scheme 3) could be isolated with semi-preparative TLC
in small amounts. The reaction mechanism for the forma-
tion of 5b, 7b, 8b is not quite evident. Intermediate species
like ArSnMe2F come into question but could neither be
isolated nor detected in the crude reaction mixture (e.g.
19F NMR).
Molecules with carbanionic structures such as 4a and
some functionalized aryllithiums can be fluorinated in
moderate yield with FClO3 [8] and [18F]FClO3 [12]. We
adopted the first reaction and obtained 2-fluoro-malonic
acid diethyl ester in high yield. The precipitated solid was
separated and characterized by anion chromatography to
consist mainly of (sodium) chlorate (4c, see Scheme 2).
Fluoride as well as traces of acetate and formiate were
identified as by-products.
In a further experiment, we prepared naphthalen-1-yl-
lithium (3) and tried to react it with FClO3. 3 is a reactive
and rather instable compound [14] and was characterized
as adduct with diethyl ether by 1H NMR. Contrary to
the results obtained with naphthalen-2-yl-lithium [8], no
fluorinated product was formed even under varying reac-
tion conditions in agreement with Schuetz et al. [15].
2.2.2. Reaction of substituted aromatic trimethyltin
compounds with FClO3
In order to test the behaviour and reactivity of 1a–e,
these substances were reacted according to their increasing
nucleophilicity with FClO3 (cf. Scheme 1).
The nitro compound 1a was reacted according to method
A. At 60 ꢂC and prolonged reaction time (60 min) only
small amounts of a white solid precipitated. TLC analysis
of the product mixture revealed the formation of three
new trace compounds. Two reaction products could be iso-
lated by semi-preparative TLC and identified as nitroben-
zene (5a) and dimethyl-bis-(4-nitro-phenyl)-stannane (5b),
a yellow solid. The expected product 4-fluoro-1-nitroben-
zene could not be detected. We conclude that the reactivity
of FClO3 is insufficient to achieve the electrophilic fluorina-
tion of the deactivated aromatic moiety.
The electron rich aromatics 1b and 1c should be more
reactive for electrophilic fluorination with FClO3. The
BOC (tert-butoxycarbonyl) group in 1b however, both
reduces the electron donating effect of the amino group
and resonance-stabilizes the free electron pair at nitrogen.
Compounds 1b, 1c were reacted according to methods A
and B. In both cases three reaction products were observed
at 60 ꢂC. The contemporaneous precipitation of a white
solid was promoted by the addition of petroleum ether.
This solid substance, soluble only in polar solvents like
MeOH or DMSO, shows a very high melting point and
could be identified as trimethyl tinfluoride (6). This com-
pound has a chain-like polymer structure [Me3SnF]n with
fluorine bridges [16]. Phenyl-carbamic acid tert-butyl ester
(7a) and methoxy-benzene (8a) were separated from the
reaction mixture by chromatographic procedures and iden-
tified as other major products, respectively. 1-Fluoro-
4-methoxy-benzene was only formed in trace amounts,
The reaction of the precursors containing amino groups
1d, 1e showed a different behaviour. Reactions of 1d with
FClO3 according to method A and B resulted in a violet
coloured solution. Several new compounds were detected
Scheme 3.

3740
A. Hiller et al. / Journal of Organometallic Chemistry 691 (2006) 3737–3742
by TLC. 4-Fluoroaniline could not be verified by ESI-MS
in the reaction mixture. The N,N-dimethylamino com-
pound 1e revealed a similar behaviour. During passing a
stream of FClO3 in nitrogen through the reaction mixture
the solution turned violet and three new reaction products
occurred at low and ambient temperature. Warming at ele-
vated temperature led to at least 6 compounds. Again a
relative large amount of 6 was isolated. (4-Fluoro-
phenyl)-dimethyl-amine and dimethyl-phenyl-amine (9a)
were detected as trace products by NMR. In particular,
two strongly polar components were formed. One could
be separated and identified as N-(4-chloro-phenyl)-N-
methyl-formamide (9b) (Scheme 3). In contrast to the reac-
tions described above, starting compound was not present
in the reaction mixture. Table 2 summarizes the relative
product distribution for the reaction of 1a–c and 1e with
FClO3.
The oxidizing properties of FClO3 are responsible for
the formation of a broad variety of by-products and the
sensitive amino function will undergo numerous subse-
quent reactions that prevent the fluorination of the aro-
matic ring. Formation of 9b can be explained with both
the substitution of the SnMe3 moiety by chlorine and the
oxidation of one N-methyl group. The reaction of FClO3
with amines results in the formation of N–F compounds
and oxidation products which are often unstable [22].
The fluorination of phenylamine and dimethyl-phenyl-
amine with CsSO4F failed as well [23]. Some N-containing
and amino-substituted heterocycles afforded corresponding
N-fluoro-derivatives under mild conditions [24].
nents. Accordingly, 18F-labelled FClO3 is of minor interest
for the labelling of aromatic substances with 18F, even if it
can be synthesized directly from n.c.a. [18F]HF.
4. Experimental
4.1. General
Chemical reagents were purchased from standard
commercial suppliers and were used without further purifi-
cation. For column chromatography Merck silica gel 60
was used. Melting points were determined with a Buchi B-
¨
545 apparatus. 1H NMR (300 or 400 MHz), 19F NMR
(282 MHz) and 119Sn NMR (150 MHz) spectra were
obtained on either a Varian Gemini or Bruker DRX-400
spectrometer, respectively and referenced to residual sol-
vent signals or to the N scale with reference to SnMe4
(
119Sn). Thin-layer chromatography (TLC) was performed
on silica gel 60F254 precoated plates, and spots were visual-
ized under UV light or in a iodine chamber in the case of
malonate derivatives. IR spectra were measured on KBr
cards using a Perkin Elmer FT-IR spectralphotometer sys-
tem 2000. ESI-, EI- and FAB-mass spectra were obtained
with a Bruker APEXII (7 Tesla, in dichloromethane/
methanol), Thermo Electron MAT 95 (70, 16 eV) and VG
ZAB-HSQ (matrix 3-nitrobenzyl alcohol) instrument,
respectively.
When products formed could not be isolated, yields
1
were estimated from % conversion judged by H NMR
analysis.
Finally, compound 2 was tested according to method A
and B, and with petroleum ether as solvent. The major por-
tion of 2 did not react, a small amount of 6 was separated
and three trace components were found but not further
investigated. 1-Fluoro-naphthalene could not be verified.
4.2. Preparation of precursor substances
4.2.1. Trimethyl-(4-nitro-phenyl)-stannane (1a)
1
m.p. 51–53 ꢂC; H NMR (CDCl3) d 0.37 (9H, s, CH3),
7.68 (2H, d, J = 8.2 Hz, Har), 8.15 (2H, d, Har). 119Sn
1
3. Conclusions
NMR (CDCl3) d À21 (s, Sn–CH3, H decoupled).
FClO3 as a weak EFA is not a suitable agent for the
fluorination or radiofluorination of trimethyltin com-
pounds to produce radiopharmaceuticals. The reactivity
of FClO3 is not sufficient for the electrophilic fluorination
of the substituted aromatic trimethyltin compounds 1a–e.
Even compounds with high nucleophilicity show a very
low SnMe3 for F exchange. A series of substituted diphenyl
dimethyltin compounds were recorded as trace compo-
4.2.2. (4-Trimethylstannanyl-phenyl)-carbamic acid tert-
butyl ester (1b)
A solution of n-BuLi in n-hexane (1.3 mL, 2 mmol)
was added dropwise to a stirred solution of (4-bromo-
phenyl)-carbamic acid tert-butyl ester (272 mg, 1 mmol)
in anhydrous THF (8 mL) at À78 ꢂC under nitrogen
followed by dropwise addition of trimethyltin chloride
(397 mg, 2 mmol) in THF (4 mL). The solution was
Table 2
Overview of the relative product distribution for the reaction of 1a–c and 1e with FClO3
SnMe3
compound
Number of
spots (TLC)
Starting
compound
Yield F-aromatic
Yield Me3SnF (6) (%)
Yield destannylated
compound (%)
Isolated by-product
1a
1b
1c
1e
4
4
4(5)
P6
++
+
+
n.d.
n.d.
Traces
Traces
17
40
40
52
11 (5a)
52 (7a)
34 (8a)
12 (9a)
Diarylstannane (5b)
Diarylstannane (7b)
Diarylstannane (8b)
(9b)
n.d.
++ detectable, + detectable, n.d. not detectable.

A. Hiller et al. / Journal of Organometallic Chemistry 691 (2006) 3737–3742
3741
stirred for 30 min gradually warmed up to À40 ꢂC, and
4.3. Preparation of and reactions with perchlorylfluoride
further 1.5 h with gradual warming up to room
temperature. After addition of saturated aqueous NH4Cl
(ꢀ70 mL), the mixture was extracted with diethyl ether
(3 · 15 mL). The combined organic layers were washed
with water, dried and concentrated resulting in an oily
residue. The crude product was purified over column
chromatography (Kieselgel 60; /: 30, h: 145 mm)
using n-hexane/ethyl acetate 10:1 for elution. After
evaporation of the solvent nearly pure 1b was isolated
(290 mg, 81%).
Perchlorylfluoride according to [9], slightly modified.
A mixture of potassium perchlorate (usually 50 mg,
0.36 mmol) in fluorosulfonic acid (220 lL, 3.8 mmol) was
charged into a 8 mL glass vial and stirred under gradual
warming up to ꢀ95 ꢂC. FClO3 was flushed with moderate
N2 flow, purified through a column filled with solid sodium
thiosulfate and ascariteꢃ (10–35 mesh) and transferred
into the precursor solution.
4.3.1. General protocol for fluorination experiments with
FClO3
A mixture of (4-iodo-phenyl)-carbamic acid tert-butyl
ester (319 mg, 1 mmol), hexamethyl-distannane (240 lL,
1.15 mmol) and tetrakis(triphenylphosphine) palladium(0)
(15 mg, 13 lmol) in dry toluene (5 mL) was stirred under
nitrogen and heated to 100 ꢂC. The solution was cooled
to ambient temperature after 15 min, filtered over Celite,
and the solvent was evaporated under reduced pressure.
The crude product was purified over column chromatogra-
phy (Kieselgel 60; /: 32 mm, h: 130 mm) using petroleum
ether/diethylether 5:1 for elution. The evaporation of sol-
vents from the appropriate fractions, checked by TLC,
afforded 1b as white needles (289 mg, 81%).
Method A. About 150–300 lmol of the aromatic trim-
ethyltin precursor dissolved in dry THF (61 mL) was
cooled at À60 ꢂC. The FClO3/N2 mixture was passed
through the precursor solution for approx. 35 min. After
sealing the vial, the solution was warmed up to ambient
temperature under stirring and stirred at approx. 60 ꢂC
for further 20 min (‘‘closed’’ conditions).
Method B. The same procedure as described above but
with the introduction of FClO3 at ꢀ0 ꢂC, further reaction
at room temp. and approx. 60 ꢂC under ‘‘open’’ conditions.
1
m.p. 85–86 ꢂC; H NMR (CDCl3) d 0.26 (9H, s, CH3),
4.3.2. 2-Fluoro-malonic acid diethyl ester (4b)
1.51 (9H, s, tert-Bu), 6.43 (1H, s, NH), 7.33 (2H, d,
J = 8.4 Hz, Har), 7.40 (2H, d, Har). 119Sn NMR (CDCl3)
According to B. After separation of the white solid iden-
tified as sodium chlorate (4c) the isolated organics con-
sisted of 4b (84%) and 2,2-difluoro-malonic acid diethyl
1
d À27 (s, Sn–CH3, H decoupled). Anal Calc.: (C14H23-
NO2Sn) C, 47.23; H, 6.51; N, 3.93. Found: C, 47.60; H,
6.53; N, 3.76.
1
ester (16%) according to H and 19F NMR.
4.3.3. Reaction of 1a with FClO3 (200 lmol)
Nitro-benzene (5a). 3 mg, yield 11%; H NMR spectro-
scopic data agree with published ones.
4.2.3. (4-Methoxy-phenyl)-trimethyl-stannane (1c)
1H NMR (CDCl3) d 0.26 (9H, s, CH3), 3.81 (3H, s,
OCH3), 6.92 (2H, d, J = 8.4 Hz, Har), 7.41 (2H, d, Har).
1
Trimethyltin fluoride (6). 6.1 mg, yield 17%; m.p.
>330 ꢂC; RFA: 25.27 keV (Sn, Ka), 28.48 keV (Sn, Kb);
4.2.4. 4-Trimethylstannanyl-phenylamine (1d)
1H NMR (CDCl3) d 0.23 (9H, s, CH3), 3.65 (2H, s,
NH2), 6.70 (2H, d, J = 8.1 Hz, Har), 7.27 (2H, d, Har).
IR (KBr); m 2855, 2928, 1186, 555 cmÀ1
.
1H NMR
1
(DMSO-d6): d 0.35 (3H, s, JSn-H = 67.8 Hz, Sn–CH3), H
NMR (CD3OD): d 0.46 (3H, s, CH3). 19F NMR
(DMSO-d6): d À162, 19F NMR (CD3OD): d À168. 119Sn
NMR (CD3OD): d 47 (d, JSn–F = 1773 Hz, 1H decoupled).
Anal. Calc. for C3H9FSn: C, 19.71; H, 4.96. Found: C,
20.09; H, 5.10.
4.2.5. Dimethyl-(4-trimethylstannanyl-phenyl)-amine (1e)
1
m.p. 38–39 ꢂC; H NMR (CDCl3) d 0.25 (9H, s, CH3),
2.95 (6H, s, NCH3), 6.77 (2H, d, J = 8.7 Hz, Har), 7.37
(2H, d, Har).
Dimethyl-bis-(4-nitro-phenyl)-stannane (5b). 4.5 mg;
yellow solid; Rf 0.30 (petroleum ether/ethyl acetate 10:1).
IR: m 3033, 2854–2955, 1574, 1346, 1595, 1514, 1188,
4.2.6. Trimethyl-naphthalen-1-yl-stannane (2)
1H NMR (CDCl3) d 0.44 (9H, s, JSn–H = 54 Hz, CH3),
7.47 (3H, m, Har), 7.65 (1H, d, Har), 7.84 (3H, m, Har).
522 cmÀ1 1H NMR (CDCl3) d 0.67 (3H, s, JSn-H
. =
56.4 Hz, Sn–CH3), 7.67 (2H, d, Har), 8.19 (2H; d,
1
J = 7.8 Hz). 119Sn NMR (CDCl3): À51 (s, H decoupled).
4.2.7. Naphthalen-1-yl-lithium (3)
EI-MS m/z: 386 [M]+, 371 [M À CH3]+, 264
[M À C6H4NO2]+.
1H NMR (C6D6/THF-d8 3:1) d Har: 7.48 (1H, t), 7.60
(2H, m), 7.83 (1H, d), 7.95 (1H, d), 8.53 (1H, d), 8.66
(1H, d); – coordinated with 2 molecules diethyl ether:
CH3 1.13 (3H, t), OCH2 3.31 (2H, q).
4.3.4. Reaction of 1b with FClO3 (150 lmol)
Phenyl-carbamic acid tert-butyl ester (7a). 15 mg, yield
52%; m.p. and H NMR spectroscopic data accord with
the literature data. Anal. Calc. for C11H15NO2: C, 68.37;
H, 7.82; N, 7.25. Found: C, 68.45; H, 8.03; N, 7.43.
(THF-d8/cyclohexane-d12 1:2) d Har: 7.14 (2H, m), 7.22
(1H, t), 7.35 (1H, d), 7.58 (1H, d), 8.17 (1H, d), 8.21 (1H,
d); – coordinated with 2 molecules diethyl ether: CH3
1.13 (3H, t), OCH2 3.39 (2H, q).
1

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A. Hiller et al. / Journal of Organometallic Chemistry 691 (2006) 3737–3742
Trimethyltin fluoride (6). 11.5 mg, yield 40%, analytical
Hey-Hawkins (Institut fur Organische Chemie, Universita¨t
¨
data see above.
Leipzig) for valuable comments.
Bis-[4-(tert-butoxycarbonyl-amino)-phenyl]-dimethyl-
stannane (7b). 4 mg; white solid; Rf 0.27 (petroleum ether/
ethyl acetate 10:1).
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Radiopharm. 48 (2005) 241.
[2] H.H. Coenen, S.M. Moerlein, J. Fluorine Chem. 36 (1987) 63.
[3] A.S. Narula, M.R. Zalutsky, Radiochim. Acta 47 (1989) 131.
[4] H. Ali, J.E. van Lier, Synthesis (1996) 423.
IR: m 3330, 3015, 2856–2978, 1703, 1589, 1515,
515 cmÀ1
.
1H NMR (CDCl3) d 0.45 (3H, s, JSn–H
= 54.3 Hz, Sn–CH3), 1,51 (9H, s, tert-Bu), 6.43 (1H, s,
NH), 7.33 (2H, d, Har), 7.40 (2H, d, Har). 119Sn NMR
1
[5] M. Namavari, A. Bishop, N. Satyamurthy, G. Bida, J.R. Barrio,
Appl. Radiat. Isot. 43 (1992) 989.
(CDCl3): d À56 (s, H decoupled).
ESI-MS m/z: 535 [M]+ C24H35N2O4120Sn det., 557
[6] A. Engelbrecht, H. Atzwanger, J. Inorg. Nucl. Chem. 2 (1956) 348.
[7] G. Barth-Wehrenalp, J. Inorg. Nucl. Chem. 2 (1956) 266.
[8] M. Schlosser, G. Heinz, Chem. Ber. 102 (1969) 1944.
[9] H. Fujisawa, Y. Takeuchi, J. Fluorine Chem. 117 (2002) 173, and
references cited therein.
[M + Na]+, 1067 [2M]+.
4.3.5. Reaction of 1c with FClO3 (300 lmol)
Methoxy-benzene (8a). 11 mg, yield 34%. 1H NMR
spectroscopic data are identical with published ones.
Trimethyltin fluoride (6). 22 mg, yield 40%, analytical
data see above.
[10] S.D. Taylor, C.C. Kotoris, G. Hum, Tetrahedron 55 (1999) 12431,
and references cited therein.
[11] A. Jordanova, J. Steinbach, B. Johannsen, in: 14th International
Symposium on Radiopharmaceutical Chemistry, Interlaken Switzer-
land, June10–15, 2001, J. LabelledCompd.Radiopharm. 44(2001)901.
[12] R.E. Ehrenkaufer, R.R. MacGregor, Int. J. Appl. Radiat. Isot. 34
(1983) 613.
Bis-(4-methoxy-phenyl)-dimethyl-stannane (8b). 3.5 mg;
semisolid substance; Rf 0.54 (petroleum ether/ethyl acetate
10:1).
[13] (a) P.-Z. Tan, R.M. Badwin, T. Fu, D.S. Charney, R.B. Innis, J.
Labelled Compd. Radiopharm. 42 (1999) 457;
1H NMR (CDCl3) d 0.46 (3H, s, JSn–H = 54.6 Hz, Sn–
CH3), 3.81 (3H, s, OCH3), 6.93 (2H, d, J = 8.4 Hz, Har),
7.43 (2H, d, Har).
(b) K. Pieterse, J.A.J.M. Vekemans, H. Kooijman, A.L. Spek, E.W.
Meijer, Chem. Eur. J. 6 (2000) 4597;
(c) C. Eaborn, H.L. Hornfeld, D.R.M. Walton, J. Organomet. Chem.
10 (1967) 529;
(d) H. Azizian, C. Eaborn, A. Pidcock, J. Organomet. Chem. 215
(1981) 49;
FAB-MS m/z: 356 [M]+, 341 [M À CH3]+, 249
[M À C6H4OCH3]+; EI-MS m/z: 341 [M À CH3]+.
4.3.6. Reaction of 1e with FClO3 (200 lmol)
Dimethyl-phenyl-amine (9a). 3 mg, yield 12%. 1H NMR
spectroscopic data agree with published ones.
Trimethyltin fluoride (6). 19 mg, yield 52%, analytical
data see above.
(e) L.A. Khawli, A.I. Kassis, Nucl. Med. Biol. 19 (1992) 297;
(f) V.S. Zavgorodnii, L.E. Mikhailov, A.V. Novoselov, Russ. J. Org.
Chem. 32 (1996) 879 (in Russian);
(g) M. Bullpitt, W. Kitching, J. Organomet. Chem. 116 (1976) 161.
´
[14] F.H. Carre, C. Chuit, R.J.P. Corriu, W.E. Douglas, D.M.H. Guy, C.
´
Reye, Eur. J. Inorg. Chem. (2000) 647.
N-(4-Chloro-phenyl)-N-methyl-formamide (9b). 4 mg;
Rf 0.56 (petroleum ether/ethyl acetate 1:1).
IR; m 3030, 2976, 2924, 2854, 1682, 1597, 1497,
[15] R.D. Schuetz, D.D. Taft, J.P. O’Brien, J.L. Shea, H.M. Mork, J.
Org. Chem. 28 (1963) 1420.
[16] Gmelin Handbook of Inorganic Chemistry, Sy-no. 46 Sn, Sn-organic
Compounds, eighth ed., 1978, pp. 13–19 (part 5).
[17] J.A. Gamboa, A. Sundararaman, L. Kakalis, A.J. Lough, F. Ja¨kle,
Organometallics 21 (2002) 4169.
[18] W.A. Sheppard, Tetrahedron Lett. (1969) 83.
[19] C.E. Inman, R.E. Oesterling, E. Tyczkowski, J. Am. Chem. Soc. 80
(1958) 5286.
[20] D.M. Gardner, R.E. Oesterling, F.L. Scott, J. Org. Chem. 28 (1963)
2650.
1116 cmÀ1
.
1H NMR (CDCl3) 2 rotamers ꢀ2:1, d 3.33/3.30 (3H, s,
N-CH3), 7.18/7.11 (2H, d, Har), 7.43/7.38 (2H, d, Har),
8.48/8.45 (1H, s, CHO).
EI-MS m/z: 169 [M]+, 140 [M À CHO]+, 134 [M À Cl]+,
77 [C6H5]+.
[21] A. Jordanova, Investigations of electrophilic fluorination with
n.c.a. 18F, Ph.D. Thesis, Technische Universita¨t Dresden, Ger-
many, 2003.
Acknowledgements
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(1967) 1115.
[23] S. Stavber, M. Zupan, J. Org. Chem. 50 (1985) 3609.
[24] A.A. Gakh, S.V. Romaniko, B.I. Ugrak, A.A. Fainzelberg, Tetrahe-
dron 47 (1991) 7447.
We thank the ‘‘Sa¨chsisches Staatsministerium fur Wis-
¨
senschaft und Kunst’’ for financial grant of this work (Pro-
ject No. 4-7531.50-02-941-02/1). We are grateful to Prof. E.