Alkyltelluro Substitution Improves the Radical-Trapping Capacity of Aromatic Amines

Article abstract of DOI:10.1002/chem.201602377

The synthesis of a variety of aromatic amines carrying an ortho-alkyltelluro group is described. The new antioxidants quenched lipidperoxyl radicals much more efficiently than α-tocopherol and were regenerable by aqueous-phase N-acetylcysteine in a two-phase peroxidation system. The inhibition time for diaryl amine 9 b was four-fold longer than recorded with α-tocopherol. Thiol consumption in the aqueous phase was found to correlate inversely to the inhibition time and the availability of thiol is the limiting factor for the duration of antioxidant protection. The proposed mechanism for quenching of peroxyl radicals involves O-atom transfer from peroxyl to Te followed by H-atom transfer from amine to alkoxyl radical in a solvent cage.

Full text of DOI:10.1002/chem.201602377

DOI: 10.1002/chem.201602377
Full Paper
&
Catalytic Antioxidants
Alkyltelluro Substitution Improves the Radical-Trapping Capacity
of Aromatic Amines
Jia-fei Poon,[a] Jiajie Yan,[a] Vijay P. Singh,[a] Paul J. Gates,[b] and Lars Engman*[a]
Abstract: The synthesis of a variety of aromatic amines car-
rying an ortho-alkyltelluro group is described. The new anti-
oxidants quenched lipidperoxyl radicals much more efficient-
ly than a-tocopherol and were regenerable by aqueous-
phase N-acetylcysteine in a two-phase peroxidation system.
The inhibition time for diaryl amine 9b was four-fold longer
than recorded with a-tocopherol. Thiol consumption in the
aqueous phase was found to correlate inversely to the inhib-
ition time and the availability of thiol is the limiting factor
for the duration of antioxidant protection. The proposed
mechanism for quenching of peroxyl radicals involves O-
atom transfer from peroxyl to Te followed by H-atom trans-
fer from amine to alkoxyl radical in a solvent cage.
Early on,[3] electron-donating substituents such as methoxyls
or methyls that could stabilize the developing phenoxyl radical
were found to lower the OꢀH bond dissociation enthalpy and
increase reactivity towards peroxyl radicals. It was also realized
that the orientation of the lone pairs of an oxygen substituent
relative to the aromatic plane was critical for the stabilizing
effect. For example, this overlap is better in the ring-contracted
tocopherol 3 than in the parent 1 and the rate constant for
quenching of peroxyl radicals increases by a factor of almost
two.[4]
Introduction
Autoxidation is an undesired, stepwise, free-radical reaction
whereby organic compounds RꢀH are oxidatively converted to
the corresponding hydroperoxides, ROOH [Eq. (1)]. The most
successful way to inhibit or at least slow down the process has
been to add small amounts of a radical trapping antioxidant,
RꢀH þ O2 ! RꢀOOH
ð1Þ
ð2Þ
kinh
C
C
RꢀOO þ AꢀH
RꢀOOH þ A
ƒ!
kprop
C
C
RꢀOO þ RꢀH
RꢀOOH þ R
ð3Þ
ƒƒ!
AꢀH, which could transfer a hydrogen atom to peroxyl radicals
considerably faster [kinh =105–106 mꢀ1 ꢀ1; Eq. (2)] than the hy-
s
drocarbon RꢀH itself [kprop =up to 102 mꢀ1
s
ꢀ1; Eq. (3)] and
C
which gives rise to a relatively unreactive radical, A .
Among chain-breaking antioxidants found in biological sys-
tems or used for the stabilization of man-made materials and
products, phenols and aromatic amines clearly predominate.
Evolution gave us a-tocopherol (1) which has become a bench-
mark (kinh =3.2ꢀ106 mꢀ1 sꢀ1)[1] for a reactive phenolic antioxi-
dant and 60 years of industrial and academic experimentation
provided us with the 4,4’-dialkyldiphenylamines 2 (kinh =1.8ꢀ
The 21st century has seen more dramatic improvements in
the reactivities of radical trapping antioxidants.[5,6] In 2003
Pratt, Valgimigli and Porter published a seminal paper describ-
ing the excellent radical trapping activity of 3-pyridinols carry-
ing strongly electron-donating substituents.[7] By substitution
of CH for N in the aromatic part of a phenol, the OꢀH bond
could be weakened by para-substitution with a strongly elec-
tron-donating dimethylamino group while the ionization po-
tential of the antioxidant did not drop below the critical point
where a direct reaction with dioxygen becomes a problem. 3-
Pyridinol 4—the most reactive compound of this kind—was an
impressive 88-times more reactive towards peroxyl radicals
than a-tocopherol. More vitamin E-like compounds of this
type, which were about 15-times more reactive than the
parent, were also prepared.[8,9]
105 mꢀ1 ꢀ1),[2] which are one of the favorite additives to oils,
s
fuels and other petroleum products. Since the 1960s, consider-
able efforts have been invested to improve the radical-trap-
ping activity of phenolic compounds.
[a] J.-f. Poon, J. Yan, Dr. V. P. Singh, Prof. L. Engman
Department of Chemistry–BMC, Uppsala University, Box-576
751 23 Uppsala (Sweden)
E-mail: lars.engman@kemi.uu.se
[b] Dr. P. J. Gates
University of Bristol, School of Chemistry, Bristol, BS8 1TS (UK)
Supporting information and ORCID from the author for this article are
available on the WWW under http://dx.doi.org/10.1002/chem.201602377.
Chem. Eur. J. 2016, 22, 1 – 14
1
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
Not unexpectedly, the principles for maximizing the radical
trapping activity of phenols holds also for diaryl amine antioxi-
dants.[2] Thus, the di-3-pyridyl amine 5 was 200-times more re-
active towards peroxyl radicals than the industrial standard
diaryl amine 2 (R=C8H17).
Thus, alkyltelluro groups could be introduced in fair yields
into the ortho-position of N-methylaniline.
We have found another way to improve the performance of
phenolic antioxidants.[10] Incorporation of an alkyltelluro group
next to the OH in phenol (compound 6) was found to increase
the rate constant for quenching of peroxyl radicals by about
four orders of magnitude. Thus, compounds of this type are
about ten-fold more reactive than a-tocopherol. To account for
the high reactivities, we have proposed a rather unconvention-
al mechanism involving oxygen transfer from peroxyl radical to
tellurium, followed by H-atom transfer, in a solvent cage, from
phenol to the resulting alkoxyl radical.[11] Interestingly, in
a two-phase system designed to model a biological mem-
brane, water-soluble co-antioxidants contained in the aqueous
layer could regenerate the organotellurium antioxidant in the
lipid phase and allow for a catalytic mode of chain-breaking
activity.
In a similar fashion, N-hexadecyl-2-bromoaniline provided
lipophilic compound 8 in 51% yield. As exemplified by com-
pounds 9, the procedure also provided convenient access to
diarylamines carrying ortho-alkyltelluro substituents. It would
seem that the protocol described in Equation (4) could be sim-
plified by addition of the appropriate alkyl halide to the in situ
prepared solution of the lithium arenetellurolate formed
before oxidation. However, whenever this was tried, a difficult-
to-separate, complex mixture of products was obtained.
Our previous work[11] with alkyltelluro phenols suggested
that the radical trapping activity as well as the regenerability
was better if the two functional groups were oriented ortho
rather than para to each other. For comparison, using the
methodology shown in Equation (4), we synthesized diphenyl-
amine 10, carrying a para-hexadecyltelluro group.
In the following we describe our attempts to improve the
radical-trapping activity of aromatic amine antioxidants by al-
kyltelluro substitution. Since the valency of nitrogen is higher
than that of oxygen, the opportunities for structural variations
are richer in aromatic amines than in phenolic compounds.
Novel antioxidants prepared were evaluated both for their re-
activity towards lipidperoxyl radicals and their regenerability in
the two-phase system.
Results and Discussion
Synthesis
Only a few alkyltelluro substituted arylamines are known in the
literature and their preparation is often rather lengthy.[12,13] We
thought that tBuLi-induced lithium-halogen exchange in a bro-
moaniline derivative, followed by addition of a dialkyl ditellur-
ide as an electrophile would provide the corresponding alkyl-
telluro-functionalized aniline in a one-pot reaction. However,
all attempts to lithiate 2-bromoaniline and treat it with a dialkyl
ditelluride resulted in the formation of rather complex mixtures
from which the desired product could never be isolated in
pure form.
Curious to see if the radical trapping activity of 3-amino-
pyridines could be improved, we prepared 3-amino-2-
bromo-4,6-dimethylpyridine (11 a)[10b] and subjected it to alkyl-
telluro functionalization as described in Equation (4). Telluride
11 c was isolated in modest yield. The corresponding N-methy-
lated compound 11 d was obtained from 11 b in a similar fash-
ion.
We also explored ortho-lithiation[14] for the introduction of al-
kyltelluro groups [Eq. (5)]. Thus, Boc-protected aniline was dili-
thiated with tBuLi and allowed to react with elemental telluri-
um. After air-oxidation, the crude ditelluride obtained was re-
duced with sodium borohydride and the arenetellurolate
formed was allowed to react with butyl bromide to provide
12a in 37% yield. Deprotection to give 13a occurred by stir-
ring in methylene chloride containing trifluoroacetic acid (TFA).
The corresponding hexadecyltelluro derivative 13b was simi-
larly prepared from 12b.
We also tried to use elemental tellurium as an electrophile.
After oxidation of the resulting lithium arene tellurolate to a di-
telluride, borohydride reduction and alkylation would provide
the desired alkyltelluro functionalized aniline. Although this se-
quence of reactions returned only small amounts of the de-
sired product when 2-bromoaniline was used as a starting ma-
terial, it was useful for the preparation of the corresponding N-
alkylated products 7 [Eq. (4)].
Following a literature procedure,[15] Boc-protected tetrahy-
droquinoline was peri-lithiated with sec-BuLi. Addition of dibu-
tyl- and dihexadecyl ditelluride afforded compounds 14a and
14b, respectively, in 57 and 33% isolated yield after deprotec-
tion with TFA.
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
2
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
The acetals were then hydrolyzed and the resulting alde-
hydes 19 condensed with anilines 13 (19a with 13a and 19b
with 13b) to give the bis-functionalized amines 20a and 20b
in low yield after reduction with sodium cyanoborohydride.
2,2’-Dibromodiphenylamine (21) was converted in one pot to
the corresponding bis-alkyltelluro derivative 22 by using the
chemistry described in Equation (4) (5 equiv of tBuLi).
Alkyl aryl amines offer a possibility to install the alkyltelluro
moiety also into the alkyl part of the molecule. Compound 15
appeared as an interesting target. Separated from the nitrogen
by a three-carbon spacer, the alkyltelluro group would still be
able to interact intramolecularly with the arylamine moiety.
Compound 15 was prepared in 31% yield by dilithiation of N-
(2-bromobenzyl)aniline, followed by reaction with dibutyl ditel-
luride.
Previously, in the case of phenolic antioxidants, we observed
that compounds carrying two alkyltelluro groups showed con-
siderably better regenerability than their monofunctionalized
counterparts.[10e] Towards this end, it was envisaged to connect
two molecules of an aromatic amine antioxidant via a linker at-
tached to the nitrogen atoms. A suitable starting material 16
was obtained by allowing Boc-protected 2-bromoaniline to
react with 1,4-dibromobutane [Eq. (6)]. The desired compound
17 was then obtained in one pot after lithiation, reaction with
dioctyl ditelluride and TFA-deprotection.
In order to study the influence of electronic effects on anti-
oxidant activity, diphenylamines 23a–c were synthesized by
lithiation of 2-bromodiphenylamine, followed by addition of
the corresponding diaryl ditellurides.
For reference purposes, octyltelluro-substituted N-alkoxy-N-
methylaniline (24) and N,N-dimethylaniline (25) were prepared
from the corresponding bromo derivatives by lithiation fol-
lowed by reaction with electrophilic tellurium species.
We also thought it would be interesting to try to introduce
another alkyltelluro group into the aniline part of antioxidant
15. However, all attempts to access the desired compound 20
by dilithiation of the corresponding dibromo compound failed.
A reductive amination approach turned out to be more re-
warding [Eq. (7)]. The diethyl acetal of 2-bromobenzaldehyde
was a suitable starting material. First, butyltelluro (18a) and
hexadecyltelluro (18b) groups were introduced using the
chemistry described in Equation (4).
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
3
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
Evaluation
Also, inhibition times were extended and were often much
longer than recorded for a-tocopherol. This seems to indicate
that the organotellurium antioxidants are continuously regen-
erated by NAC. Alkyltelluro anilines 13 were among the least
regenerable compounds (Table 1) and Tinh values were shorter
than recorded for the corresponding alkyltelluro phenols 6.[10e]
The inhibition times for N-alkylated alkyltelluro anilines (7a–c,
8 and 14a–b) were clearly longer (148–342 min). However, the
best results were obtained with diphenylamines 9. Whereas
the butyltelluro compound 9a inhibited peroxidation for
237 min, the tinh for the hexadecyltelluro analogue 9b was
almost two-fold longer (461 min). Peroxidation traces for 9b
and a-tocopherol are shown in Figure 1.
The radical trapping capacity as well as the regenerability of
novel aromatic amine antioxidants were evaluated in a primi-
tive (lipid phase/aqueous phase) model of a biological mem-
brane as previously described.[10] Briefly, autoxidation of linoleic
acid in air was initiated by radicals formed during decomposi-
tion of 2,2’-azobis(2,4-dimethylvaleronitrile) (AMVN) at 428C in
chlorobenzene (lipid phase). The aqueous phase contained N-
acetylcysteine (NAC), a thiol co-antioxidant capable of regener-
ating the lipid-soluble antioxidant and thus extending the in-
hibition time, Tinh (the time during which the antioxidant could
efficiently inhibit peroxidation) beyond the value recorded in
a control experiment with pure water. The progress of peroxi-
dation was monitored by HPLC with UV detection of conjugat-
ed diene formed. Good radical trapping antioxidants (such as
a-tocopherol) keep formation of conjugated diene at a mini-
mum as long as they last (the inhibited rate of peroxidation,
For compounds 7–9 and 14 there is a trend in which regen-
erability increases as the compounds become more lipophilic.
The reasons for this are not clear. The long alkyl chains could
somehow improve regeneration by facilitating communication
between the aqueous and chlorobenzene layers in the two-
phase system. Alternatively, they could serve to stabilize the
solvent cage in the proposed mechanism (vide infra).
Rinh, is low), but then it increases markedly (Figure 1).
The ortho-substituted alkyltelluro phenols previously
tested[11] showed much better regenerability than their corre-
sponding para-substituted analogues. In line with these results,
para-substituted diphenyamine 10 (Tinh =152 min) could not
match 9b when it comes to inhibition time in the presence of
Table 1. Inhibited rates of conjugated diene formation (Rinh) and inhibi-
tion times (Tinh) in the presence and absence of NAC (1 mm) in the two-
phase system.
Antioxidant
(40 mm)
With NAC
Without NAC
[a]
[b]
[b]
Rinh [mmhꢀ1
]
Tinh [min] Rinh[a] [mmhꢀ1
]
Tinh [min]
7a
7b
7c
8
9a
9b
9c
10
11 c
11 d
13a
13b
14a
14b
15
5ꢁ1
5ꢁ1
3ꢁ1
7ꢁ2
2ꢁ1
2ꢁ1
2ꢁ1
6ꢁ1
6ꢁ2
4ꢁ0
4ꢁ1
4ꢁ2
4ꢁ1
2ꢁ1
4ꢁ1
9ꢁ3
8ꢁ3
3ꢁ1
3ꢁ0
7ꢁ1
7ꢁ3
44ꢁ7
27ꢁ5
90ꢁ4
204ꢁ5
218ꢁ7
219ꢁ4
300ꢁ6
237ꢁ1
461ꢁ10
444ꢁ6
152ꢁ2
95ꢁ5
393
449
434
544
401
393
356
290
466
532
533
444
385
235
247
460
254
269
243
348
441
311
198
470
28ꢁ2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 1. Peroxidation traces (linoleic acid hydroperoxide concentration vs.
time) recorded using compound 9b and a-tocopherol as antioxidants in the
chlorobenzene layer in the presence of NAC (1 mm) in the aqueous phase.
a-Tocopherol was used as a benchmark in the two-phase
model. It can quench two peroxyl radicals before it is all con-
sumed and the rate of linoleic acid peroxidation increases rap-
idly. Control experiments with and without NAC in the aque-
ous phase produced essentially identical peroxidation traces
(Rinh =25–28 mmhꢀ1 and Tinh =97–109 min; Table 1). Thus, a-to-
copherol is not regenerable under the conditions of our two-
phase assay. In the absence of NAC, no inhibited phase of per-
oxidation could be distinguished for the alkyltelluro-substitut-
ed aromatic amines and relatively high inhibited rates of per-
oxidation were observed (Rinh =198–544 mmhꢀ1; Table 1). This
is probably because the organotellurium catalyst has been oxi-
dized by the residual amounts of linoleic acid hydroperoxide
that is always present in commercial samples of linoleic acid.
On the contrary, primary and secondary amines carrying alkyl-
telluro groups effectively inhibited lipid peroxidation (Rinh =2–
9 mmhꢀ1) in the presence of NAC, a compound known to readi-
ly reduce tetravalent organotelluriums to the divalent state.
106ꢁ0
87ꢁ7
137ꢁ10
148ꢁ1
342ꢁ4
132ꢁ2
159ꢁ11
135ꢁ11
147ꢁ4
420ꢁ7
34ꢁ9
17
20a
20b
22
23a
23b
23c
24
410ꢁ11
279ꢁ6
134ꢁ8
54ꢁ5
25
a-tocopherol 25ꢁ1
97ꢁ5
109ꢁ2
[a] Rate of peroxidation during the inhibited phase (uninhibited rate ca.
479 mmhꢀ1). Errors correspond to ꢁSD for triplicates. [b] Inhibited phase
of peroxidation. Reactions were monitored for 680 min. Errors correspond
to ꢁSD for triplicates.
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
4
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
NAC. It was also a slightly poorer quencher of peroxyl radicals.
3-Pyridinols carrying alkyltelluro groups in position 2 have re-
cently been shown to act as regenerable and efficient radical-
trapping agents.[10a,b] It was therefore disappointing to find
that the corresponding 3-aminopyridine derivative 11 c and its
N-methyl analogue 11 d inhibited peroxidation for only about
100 min.
thiol (27 mmhꢀ1). This did not increase much when AMVN and
linoleic acid (37 mmhꢀ1
) were added and a-tocopherol
(33 mmhꢀ1) as an antioxidant. Probably, since the uncatalyzed
reaction of NAC with alkylhydroperoxides is slow, the thiol con-
sumption does not reflect the amount of hydroperoxide pres-
ent in the chlorobenzene layer.
N-Benzyl aniline 15 is the only compound where the alkyltel-
luro group is placed in the alkyl rather than the aryl part of the
molecule. Gratifyingly, peroxyl radicals were efficiently
quenched (Rinh =4 mmhꢀ1). However, as noted with some of
the other anilines, the antioxidant protection did not last for
long (Tinh =132 min).
Based on the results with alkyltelluro phenols,[10e] one would
think that aniline antioxidants carrying more than one alkyltel-
luro group would show better regenerability than their mono-
substituted counterparts. However, based on the results with
compounds 17, 20 and 22 it is not worthwhile to introduce
a second alkyltelluro group. Although the compounds carrying
two alkyltelluro groups were tested at the same concentration
(40 mm) as the mono-functionalized antioxidants, regenerability
was often poorer (22 vs. 9b and 17 vs. 7b) for the more com-
plex compound.
Table 2. NAC consumption in the aqueous phase during a two-phase
peroxidation experiment.
Antioxidant
(40 mm)
Rate of NAC-consumption
[a]
[mmhꢀ1
]
7b
9b
9c
10
11 d
13b
14b
15
17
20b
22
23a
23b
23c
24
25
222ꢁ18
146ꢁ13
150ꢁ14
321ꢁ22
736ꢁ18
458ꢁ27
274ꢁ10
586ꢁ21
305ꢁ14
415ꢁ18
187ꢁ8
160ꢁ5
126ꢁ10
188ꢁ8
500ꢁ16
538ꢁ26
33ꢁ4
In diphenylamines 23 the electron density at tellurium is
varied in a systematic way. As shown in Table 1, there is
a trend that electron-withdrawing substituents cause a reduc-
tion in the inhibition time (23b>23a>23c). Furthermore,
compound 23c carrying a 4-CF3-C6H4Te-group was considera-
bly less reactive (Rinh =44 mmhꢀ1) towards peroxyl radicals than
the other two. Replacement of a para-hydrogen for a methoxy
group in the aryl part of the diphenylamine (compound 9c vs.
9b) only influenced the antioxidative properties marginally.
Compounds 24 and 25 represent anilines lacking an NꢀH
bond. None of them could inhibit peroxidation for long in the
presence of NAC and both of them (Rinh =27 and 90 mmhꢀ1, re-
spectively) were poor radical-trapping agents. It may be that
these compounds quench peroxyl radicals by electron transfer,
followed by disproportionation of the resulting, labile, TeIII spe-
cies.
a-tocopherol
NAC+linoleic acid+AMVN
NAC
37ꢁ8
27ꢁ5
[a] Errors correspond to ꢁSD for triplicates.
In support of this hypothesis, addition of telluride 25 after
140 min to the ongoing peroxidation caused a notable in-
crease in the consumption of NAC (Figure 2). The telluride is
known to catalyze (via telluroxide formation) the thiol-induced
reduction of hydroperoxides. Thiol consumption was also re-
corded with most of the aromatic amine antioxidants (Table 2).
Although their reactivity towards peroxyl radicals were very
similar (as judged from the Rinh values in Table 1), NAC con-
sumption varied a lot and was often much higher than record-
ed with a-tocopherol. Overall, the inhibition time recorded
was inversely related to the thiol consumption. Thus, diaryla-
The two-phase system for assessment of reactivity and re-
generability of novel antioxidants relies on analysis of conju-
gated diene formed in the organic phase. Only rarely,[10b] have
we tried to study what is going on in the aqueous phase.
What we have seen is that NAC is oxidized to the correspond-
ing disulfide. In order to follow the thiol consumption more
carefully during a peroxidation experiment, the aqueous phase
was sampled every 30 min and allowed to react with bis-4-pyr-
idyl disulfide (Aldrithiol-4TM). The concentration of pyridine-4-
thiol formed in the substitution reaction with NAC [Eq. (8)] was
then determined spectrophotometrically at 324 nm.
Figure 2. NAC concentration versus time during a normal peroxidation ex-
periment with a-tocopherol (40 mm) as an antioxidant. After 140 min, tellur-
ide 25 (40 mm) was added.
A control experiment with nothing but NAC in the two-
phase system (Table 2) showed a slow consumption of the
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
5
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
mines 9b, 9c and 23b showed the longest Tinh values (>
400 min) and the slowest rates of thiol consumption (ꢂ
150 mmhꢀ1). The fastest rates of thiol consumption were re-
start new chains and for every oxygen-transfer event two
equivalents of thiol are used up to reduce telluroxide to tellur-
ide. Under such conditions the thiol in the aqueous phase will
be rapidly consumed, catalyst will be converted to its oxidized
inactive form and peroxidation will increase to the uninhibited
rate. Inefficient quenching of alkoxyl radicals in the solvent
cage by para-substituted alkyltelluro diphenylamine 10 may
be the reason for its shorter Tinh and higher rate of thiol con-
sumption than the corresponding ortho-substituted compound
9b. Obviously, if hydrogen bonding to NH is important in the
solvent cage, the close (ortho) arrangement of amine and alkyl-
telluro groups is better than the distant (para).
corded with aminopyridine 11 d (736 mmhꢀ1
) and benzyl
phenyl amine 15 (586 mmhꢀ1). Both of them offered antioxi-
dant protection for only slightly more than 100 min. Reference
compounds 24 and 25, both lacking NꢀH groups, caused
a rapid consumption of thiol (500 and 538 mmhꢀ1, respectively)
but were unable to inhibit oxidation for long. The para-disub-
stituted diphenylamine 10 consumed thiol at a more than two-
fold higher rate than the corresponding ortho-disubstituted an-
alogue 9b.
Diarylaminyl radicals have for long been known to react
with peroxyl radicals to form nitroxides. After combination
with an alkyl radical, an alkoxyamine will result.[17,18] At elevat-
ed temperature homolytic cleavage of the NꢀO bond occurs,
accompanied by reactions which allow for regeneration of the
diarylamine antioxidant.[18] Curious to see if an alkoxyamine is
likely to be formed under the conditions of our two-phase
assay, we synthesized and tested compound 24. The poor per-
formance of the compound in comparison with the corre-
sponding aniline 7b brings us to conclude that alkoxyamines
are not likely to be involved in the chemistry responsible for
the antioxidant activity of aromatic amines carrying alkyltelluro
groups.
Mechanism
In our previous work with alkyltelluro phenols[11] we proposed
an unconventional antioxidant mechanism involving oxygen-
atom transfer from peroxyl radicals to tellurium, followed by
H-atom transfer from phenol to the resulting alkoxyl radical in
a solvent cage. We believe that a similar mechanism is opera-
tive with alkyltelluro anilines (Scheme 1). After transfer of
oxygen, the resulting alkoxyl radical can abstract a hydrogen
atom from the amine. Regeneration of the antioxidant from
the telluroxide/aminyl radical is brought about by the thiol
and is accompanied by disulfide formation. Whereas the thiol-
induced reduction of telluroxide to telluride is well document-
ed in the literature,[16] the reduction of an aminyl radical to
amine has little precedence. We speculate that proton-coupled
electron transfer (PCET) could be involved, facilitated by the
large chalcogen.
Conclusions
The synthesis of a variety of alkyltelluro-substituted aromatic
amines has enabled the study of their radical trapping activity
and regenerability by thiols in a two-phase lipid peroxidation
system. We found that introduction of alkyltelluro groups into
the aromatic amine scaffold causes a substantial (ca. 100-fold)
increase in the reactivity towards lipidperoxyl radicals. Also, re-
generation of the aromatic amine antioxidant by thiol co-anti-
oxidants is greatly facilitated. To account for the remarkable
antioxidative properties of the organochalcogen compounds
we propose an unconventional mechanism involving transfer
of an oxygen atom from peroxyl to tellurium, followed by hy-
drogen abstraction by the resulting alkoxyl radical. Overall, an
alcohol rather than a hydroperoxide is the final product of per-
oxidation. Conventional chain-breaking antioxidants formally
transfer a hydrogen atom to peroxyl radicals and drag them
out of the autoxidation chain reaction. However, the resulting
hydroperoxide needs to be dealt with (reduced) in a separate
step by some preventive antioxidant. Our novel antioxidants
are, at the same time, chain-breaking and peroxide-decompos-
ing and would therefore be properly described as “multifunc-
tional”. Aromatic amines are privileged when it comes to stabi-
lization of many types of petroleum-derived products. One of
the merits of these antioxidants is their capacity to trap multi-
ple radicals per molecule of amine.[19] However, the catalytic
mechanism is only operative at elevated temperatures (typical-
ly 1608C). Aromatic amines carrying an alkyltelluro group are
regenerable by thiols at considerably lower temperatures. In
this respect they are complementary to the industrially used
diarylamine antioxidants. We feel that this facile regenerability
Why is it then that certain antioxidants can delay peroxida-
tion for more than 400 min with a minimal consumption of
aqueous-phase thiol whereas others offer protection for less
than 100 min with an up to six-fold higher rate of thiol oxida-
tion? We feel that the key to success for the long-lasting anti-
oxidants is efficient quenching of alkoxyl radicals within the
solvent cage and facile reduction of the aminyl radical. Alkoxyl
radicals that diffuse out of the cage are reactive enough to
Scheme 1. Proposed mechanism for quenching of peroxyl radicals.
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
6
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
N-Methyl-2-(octyltelluro)aniline (7b): 2-Bromo-N-methylaniline
(186 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromooctane (0.2 mL, 1.0 mmol)
were reacted according to the general procedure to give the title
compound as a yellow oil (219 mg, 63%). 1H NMR (400 MHz,
CDCl3): d=7.79 (dd, J=1.6, 7.2 Hz, 1H), 7.29 (m, 1H), 6.62 (d, J=
8.0 Hz, 1H), 6.56 (m, 1H), 4.83 (s, 1H), 2.90 (s, 3H), 2.76 (t, J=
8.0 Hz, 2H), 1.74 (m, 2H), 1.28–1.38 (several peaks, 10H), 0.91 ppm
(t, J=6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=151.5, 142.7, 130.7,
117.5, 108.4, 99.8, 31.8 (2C), 31.7, 31.1, 29.2, 28.9, 22.6, 14.1,
8.4 ppm. 125Te NMR (126 MHz, CDCl3): d=278 ppm. HRMS (TOF MS
ES+) m/z calcd for C15H25NTeH [M+H]+: 350.1123. Found: 350.1123.
may be taken advantage of for the development of novel anti-
oxidants for petroleum products that are not exposed to ele-
vated temperatures during their service life (fuels, certain oils
and greases). Regeneration of tellurium-based antioxidants in
homogeneous phase by lipid soluble thiols has been previous-
ly demonstrated.[10b]
Experimental Section
1H and 13C NMR spectra were recorded on 300 MHz (1H: 300 MHz;
13C: 75 MHz), 400 MHz (1H: 399.97 MHz; 13C: 100.58 MHz) and
500 MHz (1H: 499.93 MHz; 13C: 125.70 MHz) spectrometers, using
the residual solvent peaks of CDCl3 (1H: d=7.26 ppm; 13C: d=
77.0 ppm) as an indirect reference to TMS. 125Te NMR spectra were
recorded on a 400 MHz spectrometer (125Te: 126.19 MHz) using
Ph2Te2 (d=423 ppm) as external standard. 19F NMR spectra were re-
corded on a 400 MHz spectrometer (19F: 376 MHz) using CFCl3 (d=
0.0 ppm) as external standard. The melting points are uncorrected.
Flash column chromatography was performed using silica gel
(0.04–0.06 mm). Tetrahydrofuran was dried in a solvent purification
system by passing it through an activated alumina column. Dibutyl
ditelluride,[20] dioctyl ditelluride,[21] dihexadecyl ditelluride,[22] 2-bro-
modiphenylamine,[23] diphenyl ditelluride,[24] bis(4-methoxyphenyl)
ditelluride,[25] bis(4-trifluoromethylphenyl) ditelluride,[26] N-(2-bro-
mophenyl)-N-methyl-O-propylhydroxylamine,[27] N-Boc-2-bromoani-
line,[28] N-2-bromobenzyl aniline,[29] 11 a,[10a] 18a,[24] and 19a[30] were
prepared according to literature procedures.
2-(Hexadecyltelluro)-N-methylaniline (7c): 2-Bromo-N-methylani-
line (186 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromohexadecane (0.3 mL,
1.0 mmol) were reacted according to the general procedure to
give the title compound as a yellow oil (215 mg, 47%). 1H NMR
(400 MHz, CDCl3): d=7.76 (dd, J=1.6, 7.2 Hz, 1H), 7.26 (m, 1H),
6.58 (d, J=8.4 Hz, 1H), 6.52 (m, 1H), 4.81 (s, 1H), 2.87 (s, 3H), 2.73
(t, J=7.2 Hz, 2H), 1.71 (m, 2H), 1.24–1.35 (several peaks, 26H),
0.89 ppm (t, J=6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=151.5,
142.7, 130.7, 117.5, 108.3, 99.8, 31.9, 31.8, 31.7, 31.1, 29.7 (2C), 29.6
(3C), 29.5, 29.4, 28.9, 22.7, 14.1, 8.3 ppm. 125Te NMR (126 MHz,
CDCl3): d=277 ppm. HRMS (TOF MS ES+) m/z calcd for C23H41NTeH
[M+H]+: 462.2374. Found: 462.2374.
2-Bromo-N-hexadecylaniline: To
a solution of 2-bromoaniline
(860 mg, 5 mmol) in anhydrous THF (15 mL) at ꢀ788C under nitro-
gen was added n-butyl lithium (1.6m, 3.1 mL, 5 mmol). After being
stirred for 1 h at ꢀ788C, 1-bromohexadecane (1.53 mL, 5 mmol)
was added and the solution was allowed to stir at ambient tem-
perature overnight. The solution was quenched with saturated am-
monium chloride solution (20 mL) and extracted with diethyl ether
(20 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The residue was
purified by column chromatography (pentane/ethyl acetate=
97.5:2.5) to give the title compound as a white solid (1.17 g, 59%).
M.p. 35–378C. 1H NMR (400 MHz, CDCl3): d=7.51 (dd, J=0.8,
6.4 Hz, 1H), 7.26 (m, 1H), 6.71 (d, J=6.8 Hz, 1H), 6.64 (m, 1H), 4.38
(s, 1H), 3.23 (t, J=5.6 Hz, 2H), 1.76 (m, 2H), 1.41–1.57 (several
peaks, 26H), 1.04 ppm (t, J=5.6 Hz, 3H). 13C NMR (100 MHz, CDCl3):
d=145.0, 132.2, 128.3, 117.2, 111.0, 109.5, 43.8, 32.0, 29.8, 29.7 (3C),
29.6, 29.5, 29.4, 29.3, 27.1, 22.7, 14.1 ppm. HRMS (TOF MS EI+) m/z
calcd for C22H38BrN [M]+: 395.2188. Found: 395.2194.
General procedure: introduction of alkyltelluro groups into
anilines by lithiation
To a solution of the proper bromoaniline derivate (1.0 equiv) in an-
hydrous THF (10 mL) at ꢀ788C under nitrogen, tert-butyl lithium
(1.7m, 3.0–5.0 equiv) was added. The solution was stirred for 2 h at
ꢀ788C prior to the addition of freshly ground tellurium powder
(1.0–4.0 equiv). After being stirred for 2 h at ambient temperature,
the solution was quenched with a saturated ammonium chloride
solution (10 mL) and extracted with diethyl ether (20 mLꢀ3). The
organic layer was dried over magnesium sulfate, filtered and
evaporated under reduced pressure. The crude product was dis-
solved in ethanol (25 mL) followed by addition of sodium borohy-
dride (5.0 equiv) at ambient temperature under nitrogen. After
being stirred for 15 min, the corresponding alkylbromide
(1.0 equiv) was added and the solution was allowed to stir over-
night. After addition of water (20 mL) and extraction with diethyl
ether (25 mL x 3), the organic layer was dried over magnesium sul-
fate, filtered and evaporated under reduced pressure. The residue
was purified by column chromatography (pentane/ethyl acetate=
97.5:2.5) to give the title compound.
N-Hexadecyl-2-(hexadecyltelluro)aniline (8): 2-Bromo-N-hexade-
cylaniline (397 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL,
3.0 mmol), freshly ground tellurium powder (128 mg, 1.0 mmol),
sodium borohydride (190 mg, 5.0 mmol) and 1-bromohexadecane
(0.3 mL, 1.0 mmol) were reacted according to the general proce-
dure to give the title compound as a yellow solid (343 mg, 51%).
M.p. 41–448C. 1H NMR (300 MHz, CDCl3): d=7.76 (dd, J=1.2,
6.0 Hz, 1H), 7.23 (m, 1H), 6.58 (dd, J=1.2, 8.1 Hz, 1H), 6.50 (m, 1H),
4.80 (s, 1H), 3.14 (t, J=6.6 Hz, 2H), 2.73 (t, J=7.5 Hz, 2H), 1.62–
1.74 (several peaks, 4H), 1.27–1.45 (several peaks, 52H), 0.86–
0.91 ppm (several peaks, 6H). 13C NMR (75 MHz, CDCl3): d=150.7,
142.9, 130.7, 117.3, 108.9, 99.9, 44.3, 31.9, 31.8 (2C), 29.7 (2C), 29.6,
29.5, 29.4 (2C), 29.3, 28.9, 27.3, 22.7, 14.1, 8.3 ppm. 125Te NMR
(126 MHz, CDCl3): d=278 ppm. HRMS (TOF MS ES+) m/z calcd for
C38H72NTe [M+H]+: 672.4725. Found: 672.4727.
2-(Butyltelluro)-N-methylaniline (7a): 2-Bromo-N-methylaniline
(186 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromobutane (0.1 mL, 1.0 mmol)
were reacted according to the general procedure to give the title
compound as a yellow oil (222 mg, 76%). 1H NMR (400 MHz,
CDCl3): d=7.80 (dd, J=1.6, 7.6 Hz, 1H), 7.29 (m, 1H), 6.63 (dd, J=
0.8, 8.0 Hz, 1H), 6.56 (m, 1H), 4.84 (s, 1H), 2.90 (s, 3H), 2.76 (t, J=
7.6 Hz, 2H), 1.72 (m, 2H), 1.40 (m, 2H), 0.91 ppm (t, J=7.2 Hz, 3H).
13C NMR (100 MHz, CDCl3): d=151.5, 142.7, 130.7, 117.5, 108.3,
99.7, 33.7, 31.1, 24.8, 13.3, 7.9 ppm. 125Te NMR (126 MHz, CDCl3):
d=278 ppm. HRMS (TOF MS ES+) m/z calcd for C11H17NTeH [M+
H]+: 294.0496. Found: 294.0496.
2-Bromo-5-methoxydiphenylamine: To a solution of 2-bromo-5-
methoxyaniline (1.8 g, 8.9 mmol) in DMSO (16 mL) were added cy-
clohex-2-en-1-one (1.1 mL, 12.1 mmol), iodine (1.3 g, 4.4 mmol) and
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
7
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
p-toluensulfonic acid (167 mg, 1.0 mmol) at room temperature
under nitrogen. After being stirred at 908C for 3 h, the reaction
was quenched by addition of sodium thiosulfate (100 mL 20% aq.)
and extracted by dichloromethane (100 mLꢀ3). The organic layer
was dried over magnesium sulfate, filtered and evaporated under
reduced pressure. The mixture was purified by flash column chro-
matography (pentane/ethyl acetate=97.5:2.5) to give the title
give the title compound as a pale yellow solid (133 mg, 26%). M.p.
58–608C. 1H NMR (400 MHz, CDCl3): d=7.65 (dd, J=2.4, 10.8 Hz,
2H), 7.29 (m, 2H), 7.10 (d, J=7.2 Hz, 2H), 6.97 (dd, J=7.2 Hz, 1H),
6.91 (d, J=8.0 Hz, 2H), 5.72 (s, 1H), 2.85 (t, J=7.6 Hz, 2H), 1.79 (m,
2H), 1.28–1.39 (several peaks, 26H), 0.91 ppm (t, J=6.4 Hz, 3H).
13C NMR (100 MHz, CDCl3): d=143.2, 142.3, 140.6, 129.3, 121.6,
118.5, 117.9, 100.4, 31.9 (2C), 31.8, 29.7, 29.6 (2C), 29.5, 29.3, 28.9,
22.7, 14.1, 9.1 ppm. 125Te NMR (126 MHz, CDCl3): d=495 ppm.
HRMS (TOF MS EI+) m/z calcd for C28H43NTe [M]+: 523.2458. Found:
523.2472.
1
compound as a pale yellow oil (562 mg, 23%). H NMR (400 MHz,
CDCl3): d=7.42 (d, J=8.8 Hz, 1H), 7.35 (m, 2H), 7.20 (d, J=7.6 Hz,
2H), 7.08 (dd, J=7.6 Hz, 1H), 6.84 (d, J=2.8 Hz, 1H), 6.35 (dd, J=
2.8, 8.8 Hz, 1H), 6.10 (s, 1H), 3.74 ppm (s, 3H). 13C NMR (100 MHz,
CDCl3): d=159.7, 142.2, 141.3, 133.0, 129.4, 122.9, 120.6, 106.4,
102.8, 101.5, 55.4 ppm. HRMS (TOF MS EI+) m/z calcd for
C13H12BrNO [M]+: 277.0102. Found: 277.0105.
3-Amino-2-bromo-N,4,6-trimethylpyridine (11b): To a solution of
3-amino-2-bromo-4,6-dimethylpyridine (1.2 g, 6 mmol) in anhy-
drous THF (30 mL) at ꢀ788C under nitrogen, n-butyl lithium (1.6m,
3.8 mL, 6 mmol) was added. After being stirred for 1 h, iodome-
thane was added and the reaction was allowed to stir overnight at
ambient temperature. The solution was quenched with a saturated
ammonium chloride solution (20 mL) and extracted with diethyl
ether (25 mLꢀ3). The organic layer was dried over magnesium sul-
fate, filtered and evaporated under reduced pressure. The residue
was purified by column chromatography (pentane/ethyl acetate=
95:5) to give the title compound as a yellow oil (1.14 g, 88%).
1H NMR (300 MHz, CDCl3): d=6.81 (s, 1H), 3.50 (s, 1H), 2.74 (s, 3H),
2.37 (s, 3H), 2.29 ppm (s, 3H). 13C NMR (75 MHz, CDCl3): d=151.3,
141.3, 140.3, 136.4, 125.6, 34.9, 22.9, 18.9 ppm. HRMS (TOF MS ES+)
m/z calcd for C8H11BrN2H [M+H]+: 215.0178. Found: 215.0176.
2-(Butyltelluro)diphenylamine
(9a):
2-Bromodiphenylamine
(248 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromobutane (0.1 mL, 1.0 mmol)
were reacted according to the general procedure to give the title
compound as a yellow oil (176 mg, 50%). 1H NMR (400 MHz,
CDCl3): d=7.88 (dd, J=1.6, 8.0 Hz, 1H), 7.24–7.35 (several peaks,
3H), 7.27 (m, 1H), 7.15 (m, 2H), 7.03 (m, 1H), 6.80 (m, 1H), 6.48 (s,
1H), 2.83 (t, J=7.6 Hz, 2H), 1.77 (m, 2H), 1.40 (m, 2H), 0.91 ppm (t,
J=7.2, 3H). 13C NMR (100 MHz, CDCl3): d=146.2, 143.1, 141.6,
129.7, 129.3, 121.6, 121.4, 118.8, 115.4, 105.2, 33.6, 24.9, 13.3,
8.5 ppm. 125Te NMR (126 MHz, CDCl3): d=314 ppm. HRMS (TOF MS
EI+) m/z calcd for C16H19NTe [M]+: 355.0580. Found: 355.0586.
3-Amino-4,6-dimethyl-2-(octyltelluro)pyridine (11c): 3-Amino-2-
bromo-4,6-dimethylpyridine (1.29 g, 6.0 mmol), tert-butyl lithium
(1.7m, 14 mL, 24.0 mmol), freshly ground tellurium powder
(767 mg, 6.0 mmol), sodium borohydride (1.13 g, 30.0 mmol) and
1-bromooctane (1.1 mL, 6.0 mmol) were reacted according to the
general procedure to give the title compound as a yellow oil
2-(Hexadecyltelluro)diphenylamine (9b): 2-Bromodiphenylamine
(248 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromohexadecane (0.3 mL,
1.0 mmol) were reacted according to the general procedure to
give the title compound as a pale yellow solid (326 mg, 63%). M.p.
49–528C. 1H NMR (400 MHz, CDCl3): d=7.84 (dd, J=1.6, 7.6 Hz,
1H), 7.28–7.32 (several peaks, 3H), 7.23 (m, 1H), 7.11 (d, J=8.0 Hz,
2H), 6.98 (dd, J=7.6 Hz, 1H), 6.76 (m, 1H), 6.45 (s, 1H), 2.79 (t, J=
7.6 Hz, 2H), 1.74 (m, 2H), 1.23–1.35 (several peaks, 26H), 0.91 ppm
(t, J=6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=146.3, 143.1, 141.8,
129.8, 129.3, 121.6, 121.4, 118.8, 115.4, 105.2, 31.9, 31.8, 31.6, 29.7,
29.6 (3C), 29.5, 29.4, 28.9, 22.7, 14.1, 8.9 ppm. 125Te NMR (126 MHz,
CDCl3): d=313 ppm. HRMS (TOF MS ES+) m/z calcd for C28H43NTeH
[M+H]+: 524.2530. Found: 524.2539.
1
(487 mg, 22%). H NMR (300 MHz, CDCl3): d=6.63 (s, 1H), 3.74 (s,
2H), 3.06 (t, J=7.7 Hz, 2H), 2.36 (s, 3H), 2.08 (s, 3H), 1.81 (m, 2H),
1.22–1.36 (several peaks, 10H), 0.85 ppm (t, J=6.9 Hz, 3H).
13C NMR (75 MHz, CDCl3): d=149.5, 142.0, 128.9, 127.0, 123.3, 32.0,
31.9, 31.7, 29.1, 28.8, 23.2, 22.5, 17.8, 14.0, 10.3 ppm. 125Te NMR
(126 MHz, CDCl3): d=387 ppm. HRMS (TOF MS ES+) m/z calcd for
C15H26N2TeH [M+H]+: 365.1232. Found: 365.1229.
3-Amino-N,4,6-trimethyl-2-(octyltelluro)pyridine (11d): To a solu-
tion of 11 b (180 mg, 0.8 mmol) in anhydrous THF (10 mL) at
ꢀ788C under nitrogen was added tert-butyl lithium (1.7, 1.4 mL,
2.4 mmol). After being stirred for 2 h, freshly ground tellurium
powder (102 mg, 0.8 mmol) was added and the reaction mixture
was allowed to stir overnight at ambient temperature. The solution
was quenched with saturated ammonium chloride solution (20 mL)
and extracted with diethyl ether (20 mLꢀ3). The organic layer was
dried over magnesium sulfate, filtered and evaporated under re-
duced pressure. The crude product was dissolved in ethanol
(40 mL) followed by addition of sodium borohydride (151 mg,
4 mmol) at ambient temperature under nitrogen. After being
stirred for 15 min, 1-bromoctane (0.14 mL, 0.8 mmol) was added
and the solution was allowed to stir overnight. After addition of
water (20 mL) and extraction with diethyl ether (25 mLꢀ3), the or-
ganic layer was dried over magnesium sulfate, filtered and evapo-
rated under reduced pressure. The residue was purified by column
chromatography (pentane/ethyl acetate=95:5) to give the title
compound as a pale yellow oil (96 mg, 32%). 1H NMR (400 MHz,
CDCl3): d=6.69 (s, 1H), 3.06 (t, J=7.6 Hz, 2H), 2.90 (s, 1H), 2.74 (s,
3H), 2.42 (s, 3H), 2.22 (s, 3H), 1.86 (m, 2H), 1.26–1.42 (several
peaks, 10H), 0.87 ppm (t, J=7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3):
d=154.8, 144.5, 140.3, 138.6, 122.8, 35.7, 32.3, 31.9, 31.8, 29.2, 29.0,
23.5, 22.6, 17.5, 14.1, 9.5 ppm. 125Te NMR (126 MHz, CDCl3): d=
2-(Hexadecyltelluro)-5-methoxydiphenylamine (9c): 2-Bromo-5-
methoxy-diphenylamine (300 mg, 1.1 mmol), tert-butyl lithium
(1.7m, 1.9 mL, 3.2 mmol), freshly ground tellurium powder
(137 mg, 1.1 mmol), sodium borohydride (204 mg, 5.4 mmol) and
1-bromohexadecane (0.33 mL, 1.1 mmol) were reacted according
to the general procedure to give the title compound as a pale
yellow solid (354 mg, 59%). M.p. 39–408C. 1H NMR (400 MHz,
CDCl3): d=7.82 (d, J=8.0 Hz, 1H), 7.35 (m, 2H), 7.21 (d, J=8.0 Hz,
2H), 7.04 (dd, J=7.2 Hz, 1H), 6.90 (d, J=2.4 Hz, 1H), 6.73 (s, 1H),
6.36 (dd, J=2.4, 8.4 Hz, 1H), 3.78 (s, 3H), 2.74 (t, J=8.0 Hz, 2H),
1.74 (m, 2H), 1.26–1.37 (several peaks, 26H), 0.95 ppm (t, J=7.2 Hz,
3H). 13C NMR (400 MHz, CDCl3): d=161.8, 147.9, 144.0, 142.5, 129.3,
122.0, 119.7, 106.6, 100.1, 93.9, 55.0, 31.9, 31.7, 31.5, 29.7, 29.6 (4C),
29.5, 29.3, 28.8, 22.7, 14.1, 9.2 ppm. 125Te NMR (126 MHz, CDCl3):
d=278 ppm. HRMS (TOF MS EI+) m/z calcd for C29H45NOTe [M]+:
553.2563. Found: 553.2559.
4-(Hexadecyltelluro)diphenylamine (10): 4-Bromodiphenylamine
(248 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.8 mL, 3.0 mmol),
freshly ground tellurium powder (128 mg, 1.0 mmol), sodium boro-
hydride (190 mg, 5.0 mmol) and 1-bromohexadecane (0.3 mL,
1.0 mmol) were reacted according to the general procedure to
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
8
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
444 ppm. HRMS (TOF MS ES+) m/z calcd for C16H28N2TeH [M+H]+:
379.1388. Found: 379.1389.
95:5) to give the title compound as a yellow oil (290 mg, 95%).
1H NMR (400 MHz, CDCl3): d=7.74 (dd, J=1.2, 7.6 Hz, 1H), 7.16 (m,
1H), 6.78 (dd, J=0.8, 7.6 Hz, 1H), 6.57 (m, 1H), 4.22, (s, 2H), 2.78 (t,
J=8.0 Hz, 2H), 1.72 (m, 2H), 1.36 (m, 2H), 0.88 ppm (t, J=7.6 Hz,
3H). 13C NMR (100 MHz, CDCl3): d=149.9, 142.5, 130.5, 119.0, 113.3,
99.0, 33.8, 24.9, 13.3, 7.9 ppm. 125Te NMR (126 MHz, CDCl3):
d=301 ppm. HRMS (TOF MS EI+) m/z calcd for C10H15NTe
[M]+:279.0267. Found: 279.0270.
N-Boc-2-(butyltelluro)aniline (12a): To a solution of N-Boc-aniline
(1.16 g, 6.0 mmol) in anhydrous THF (10 mL) at ꢀ408C under nitro-
gen was added tert-butyl lithium (1.7m, 7.76 mL, 13.2 mmol). The
solution was stirred for 2 h at ꢀ408C prior to the addition of fresh-
ly ground tellurium powder (842 mg, 6.6 mmol). After being stirred
for 2 h at ambient temperature, the solution was quenched with
a saturated ammonium chloride solution (20 mL) and extracted
with diethyl ether (20 mLꢀ3). The organic layer was dried over
magnesium sulfate, filtered and evaporated under reduced pres-
sure. The crude product was dissolved in ethanol (25 mL) and
sodium borohydride (684 mg, 18 mmol) was added at ambient
temperature under nitrogen. After being stirred for 15 min, 1-bro-
mobutane (0.66 mL, 6.0 mmol) was added and the solution was al-
lowed to stir overnight. The reaction was quenched with water
(20 mL) and extracted with diethyl ether (25 mLꢀ3). The organic
layer was dried over magnesium sulfate, filtered and evaporated
under reduced pressure. The residue was purified by column chro-
matography (pentane/ethyl acetate=99:1) to give the title com-
pound as a yellow oil (827 mg, 37%). 1H NMR (400 MHz, CDCl3):
d=8.07 (d, J=8.4 Hz, 1H), 7.85 (dd, J=1.2, 7.6 Hz, 1H), 7.50 (s,
1H), 7.33 (m, 1H), 6.85 (m,1H), 2.76 (t, J=7.2 Hz, 1H), 1.70 (m, 2H),
1.54 (s, 9H), 1.37 (m, 2H), 0.89 ppm (t, J=7.2 Hz, 3H). 13C NMR
(75 MHz, CDCl3): d=153.0, 142.1, 141.6, 130.3, 123.6, 118.3, 104.3,
80.4, 33.5, 28.3, 24.8, 13.3, 9.4 ppm. 125Te NMR (126 MHz, CDCl3):
d=317 ppm. HRMS (TOF MS ES+) m/z calcd for C15H23NO2TeNa
[M+Na]+: 402.0684. Found: 402.0684.
2-(Hexadecyltelluro)aniline (13b): To a solution of 12b (900 mg,
1.65 mmol) in dichloromethane (14 mL) was added trifluoroacetic
acid (0.98 mL, 12.8 mmol) under nitrogen. After being stirred for
6 h, the solution was quenched with sodium hydrogen carbonate
(30 mL) and extracted with dichloromethane (30 mLꢀ3). The or-
ganic layer was dried over magnesium sulfate, filtered and evapo-
rated under reduced pressure. The mixture was purified by flash
column chromatography (pentane/ethyl acetate=95:5) to give the
title compound as yellow crystals (403 mg, 55%). M.p. 35–388C.
1H NMR (400 MHz, CDCl3): d=7.76 (dd, J=1.6, 7.6 Hz, 1H), 7.16 (m,
1H), 6.78 (dd, J=1.2, 8.0 Hz, 1H), 6.58 (m, 1H), 4.30 (s, 2H), 2.79 (t,
J=7.6 Hz, 2H), 1.75 (m, 2H), 1.26–1.37 (m, 26H), 0.91 ppm (t, J=
6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=150.0, 142.5, 130.4,
119.0, 113.2, 99.0, 31.9, 31.8, 31.7, 29.7, 29.6 (3C), 29.5, 29.3, 28.9,
22.7, 14.1, 8.2 ppm. 125Te NMR (126 MHz, CDCl3): d=301 ppm.
HRMS (TOF MS EI+) m/z calcd for C22H39NTe [M]+: 447.2145. Found:
447.2152.
N-Boc-1,2,3,4-tetrahydroquinoline: To a solution of N-1,2,3,4-tetra-
hydroquinoline (2.0 g, 15.0 mmol) in anhydrous THF (60 mL) was
added sodium hydride (60% w.t., 660 mg, 16.5 mmol) under nitro-
gen. After reflux for 90 min, di-tert-butyl dicarbonate (3.9 g,
17.9 mmol) was added and the reaction mixture was allowed to
reflux for 2 days. The reaction was quenched with water (60 mL)
and extracted with diethyl ether (30 mLꢀ3). The organic layer was
dried over magnesium sulfate, filtered and evaporated under re-
duced pressure. The residue was purified by column chromatogra-
phy (pentane/ethyl acetate=95:5) to give the title compound as
a light yellow oil (2.94 g, 84%). The 1H and 13C spectra were in
accord with the literature.[31]
N-Boc-2-(hexadecyltelluro)aniline (12b): To a solution of N-Boc-
aniline (1.16 g, 6.0 mmol) in anhydrous THF (10 mL) at ꢀ408C
under nitrogen was added tert-butyl lithium (1.7m, 7.76 mL,
13.2 mmol). The solution was stirred for 2 h at ꢀ408C prior to the
addition of freshly ground tellurium powder (842 mg, 6.6 mmol).
After being stirred for 2 h at ambient temperature, the solution
was quenched with a saturated ammonium chloride solution
(20 mL) and extracted with diethyl ether (20 mLꢀ3). The organic
layer was dried over magnesium sulfate, filtered and evaporated
under reduced pressure. The crude product was dissolved in etha-
nol (25 mL) and sodium borohydride (684 mg, 18 mmol) was
added at ambient temperature under nitrogen. After being stirred
for 15 min, 1-bromohexadecane (1.83 mL, 6.0 mmol) was added
and the solution was allowed to stir overnight. The reaction was
quenched with water (20 mL) and extracted with diethyl ether
(25 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The residue was
purified by column chromatography (pentane/ethyl acetate=98:2)
8-(Butyltelluro)-1,2,3,4-tetrahydroquinoline (14a): To a solution
of N-Boc-1,2,3,4-tetrahydroquinoline (466 mg, 2.0 mmol) and tetra-
methylethylenediamine (0.35 mL, 2.4 mmol) in anhydrous diethyl
ether (10 mL) was added sec-butyl lithium (1.4m, 1.7 mL, 2.4 mmol)
at ꢀ788C under nitrogen. After being stirred for 2 h at ꢀ788C, di-
butyl ditelluride (884 mg, 2.4 mmol) was added and the solution
was allowed to stir at ambient temperature overnight. The solution
was quenched with a saturated ammonium chloride solution
(20 mL) and extracted with diethyl ether (20 mLꢀ3). The organic
layer was dried over magnesium sulfate, filtered and evaporated
under reduced pressure. The residue was filtered through a short
plug (pentane/ethyl acetate=100:0 to 97.5:2.5) to remove the un-
reacted dibutyl ditelluride. The evaporated crude product was dis-
solved in dichloromethane (10 mL) and trifluoroacetic acid
(0.57 mL, 7.5 mmol) was added under nitrogen. After being stirred
for 30 min, the solution was quenched with a saturated ammoni-
um chloride solution (20 mL) and extracted with dichloromethane
(10 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The mixture was
purified by column chromatography (pentane/ethyl acetate=
97.5:2.5) to give the title compound as a yellow oil (363 mg, 57%).
1H NMR (400 MHz, CDCl3): d=7.59 (m, 1H), 6.96 (dd, J=0.8, 7.6 Hz,
1H), 6.45 (t, J=7.6 Hz, 1H), 4.90 (s, 1H), 3.40 (dt, J=2.4, 5.6 Hz,
2H), 2.75–2.79 (several peaks, 4H), 1.94 (m, 2H), 1.75 (m, 2H), 1.41
(m, 2H), 0.92 ppm (t, J=7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=
147.2, 140.2, 130.6, 120.3, 117.0, 98.7, 42.5, 33.8, 27.8, 24.9, 22.1,
1
to give the title compound as a yellow oil (935 mg, 29%). H NMR
(400 MHz, CDCl3): d=8.07 (d, J=7.6 Hz, 1H), 7.85 (dd, J=1.6,
8.0 Hz, 1H), 7.50 (s, 1H), 7.33 (m, 1H), 6.85 (m, 1H), 2.75 (t, J=
8.0 Hz, 2H), 1.71 (m, 2H), 1.54 (s, 9H), 1.24–1.35 (several peaks,
26H), 0.88 ppm (t, J=7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=
153.0, 142.2, 141.6, 130.3, 123.6, 118.4, 104.3, 80.5, 31.9, 31.8, 31.5,
29.7, 29.6 (3C), 29.5, 29.3, 28.9, 28.3, 22.7, 22.3, 14.1, 14.0, 9.9 ppm.
125Te NMR (126 MHz, CDCl3): d=316 ppm. HRMS (TOF MS EI+) m/z
calcd for C27H47NOTe [M]+: 547.2669. Found: 547.2660.
2-(Butyltelluro)aniline (13a): To
a solution of 12a (400 mg,
1.1 mmol) in dichloromethane (8.5 mL) was added trifluoroacetic
acid (0.45 mL, 5.0 mmol) under nitrogen. After being stirred for 3 h,
the solution was quenched with a saturated sodium hydrogen car-
bonate solution (30 mL) and extracted with dichloromethane
(30 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The mixture was
purified by flash column chromatography (pentane/ethyl acetate=
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
9
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
13.3, 7.7 ppm. 125Te NMR (126 MHz, CDCl3): d=270 ppm. HRMS
(TOF MS ES+) m/z calcd for C13H19NTeH [M+H]+: 320.0653. Found:
320.0651.
chromatography (pentane/ethyl acetate=95:5) as eluent to give
the title compound as a yellow oil (1.42 g, 55%). H NMR (400 MHz,
1
CDCl3): d=7.59 (s, 2H), 7.12–7.27 (several peaks, 6H), 3.69 (m, 2H),
3.35 (m, 2H), 1.27–1.56 ppm (several peaks, 22H). 13C NMR
(100 MHz, CDCl3): d=153.9, 141 (2C), 133.3 (rotamer), 132.9, 130.6
(rotamer), 130.1, 128.5 (rotamer), 128.2, 128.0 (rotamer), 127.7,
123.7, 80.3 (rotamer), 79.8 (rotamer), 79.7, 49.7 (rotamer), 48.8, 28.2
(rotamer), 27.9, 26.0 (rotamer), 25.6 ppm. HRMS (TOF MS ES+) m/z
calcd for C26H35Br2N2O4 [M+H]+: 599.0943. Found: 599.0940.
8-(Hexadecyltelluro)-1,2,3,4-tetrahydroquinoline (14b): To a solu-
tion of N-Boc-1,2,3,4-tetrahydroquinoline (466 mg, 2.0 mmol) and
tetramethylethylenediamine (0.35 mL, 2.4 mmol) in anhydrous di-
ethyl ether (10 mL) was added sec-butyl lithium (1.4m, 1.7 mL,
2.4 mmol) at ꢀ788C under nitrogen. After being stirred for 2 h at
ꢀ788C, dihexadecyl ditelluride (1.69 g, 2.4 mmol) was added and
the solution was allowed to stir at ambient temperature overnight.
The solution was quenched with a saturated ammonium chloride
solution (20 mL) and extracted with diethyl ether (20 mLꢀ3). The
organic layer was dried over magnesium sulfate, filtered and
evaporated under reduced pressure. The residue was filtered
through a short plug (pentane/ethyl acetate=100:0 to 97.5:2.5) to
remove the unreacted dihexadecyl ditelluride. The evaporated
crude product was dissolved in dichloromethane (10 mL) and tri-
fluoroacetic acid (0.57 mL, 7.5 mmol) was added under nitrogen.
After being stirred for 30 min, the solution was quenched with a sa-
turated ammonium chloride solution (20 mL) and extracted with
dichloromethane (10 mLꢀ3). The organic layer was dried over
magnesium sulfate, filtered and evaporated under reduced pres-
sure. The mixture was purified by column chromatography (pen-
tane/ethyl acetate=97.5:2.5) to give the title compound as
N1,N4-Bis[2-(octyltelluro)phenyl]butane-1,4-diamine (17): To a so-
lution of 16 (724 mg, 1.2 mmol) in anhydrous THF (10 mL) at
ꢀ788C under nitrogen, tert-butyl lithium (1.7m, 2.4 mL, 4.8 mmol)
was added. The solution was stirred for 3 h at ꢀ788C before the
addition of dioctyl ditelluride (1.41 g, 2.4 mmol). After being stirred
overnight at room temperature, the solution was quenched with
a saturated ammonium chloride solution (30 mL) and extracted
with diethyl ether (40 mLꢀ3). The organic layer was dried over
magnesium sulfate, filtered and evaporated under reduced pres-
sure. The mixture was purified on a short silica plug using pen-
tane/ethyl acetate (100:0 to 95:5) as eluent to remove the unreact-
ed dioctyl ditelluride. To the evaporated crude product dissolved in
dichloromethane (5 mL) was added trifluoroacetic acid (0.82 mL,
10.8 mmol) under nitrogen. After being stirred for 4 h, another por-
tion of trifluoroacetic acid (0.82 mL, 10.8 mmol) was added and the
reaction was allowed to stir for 2 h. The reaction was quenched
with a saturated sodium hydrogen carbonate solution (10 mL) and
extracted with dichloromethane (20 mLꢀ3). The organic layer was
dried over magnesium sulfate, filtered and evaporated under re-
duced pressure. The mixture was purified by flash column chroma-
tography (pentane/ethyl acetate=97.5:2.5) as eluent to give the
1
a yellow oil (320 mg, 33%). H NMR (400 MHz, CDCl3): d=7.55 (m,
1H), 6.92 (dd, J=1.6, 7.6 Hz, 1H), 6.42 (t, J=7.6 Hz, 1H), 4.86 (s,
1H), 3.37 (t, J=5.2 Hz, 2H), 2.71–2.76 (several peaks, 4H), 1.92 (m,
2H), 1.72 (m, 2H), 1.22–1.35 (several peaks, 26H), 0.89 ppm (t, J=
7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=147.3, 140.3, 130.7,
120.3, 117.0, 98.7, 42.6, 31.9, 31.8, 31.7, 29.7 (2C), 29.6 (2C), 29.5,
29.3, 28.9, 27.9, 22.7, 22.2, 14.1, 8.2 ppm. 125Te NMR (CDCl3): d=
269 ppm. HRMS (TOF MS EI+) m/z calcd for C25H43NTe [M]+:
487.2458. Found: 487.2456.
1
title compound as a yellow oil (327 mg, 38%). H NMR (400 MHz,
CDCl3): d=7.84 (dd, J=1.6, 7.6 Hz, 2H), 7.29 (m, 2H), 6.65 (dd, J=
0.8, 8.4 Hz, 2H), 6.58 (m, 2H), 4.90 (s, 2H), 3.27 (t, J=5.6 Hz, 4H),
2.78 (t, J=8.0 Hz, 4H), 1.87 (m, 4H), 1.77 (m, 4H), 1.31–1.41 (several
peaks, 20H), 0.95 ppm (t, J=7.2 Hz, 6H). 13C NMR (100 MHz, CDCl3):
d=150.4, 142.8, 130.6, 117.5, 108.8, 100.1, 44.0, 31.7(2C), 29.1, 28.8,
26.9, 22.6, 14.0, 8.3 ppm. 125Te NMR (126 MHz, CDCl3): d=279 ppm.
HRMS (TOF MS ES+) m/z calcd for C32H53BN2Te2 [M+H]+:725.2328.
Found: 725.2333.
N-(2-(Butyltelluro)benzyl)aniline (15): To a solution of N-(2-bromo-
benzyl)aniline (262 mg, 1 mmol) in anhydrous THF (15 mL) at
ꢀ788C under nitrogen was added tert-butyl lithium (1.7m, 1.76 mL,
3.0 mmol). After being stirred for 2 h at ꢀ788C, dibutyl ditelluride
(368 mg, 1.0 mmol) was added and the solution was allowed to
stir at ambient temperature overnight. The solution was quenched
with a saturated ammonium chloride solution (20 mL) and extract-
ed with diethyl ether (20 mLꢀ3). The organic layer was dried over
magnesium sulfate, filtered and evaporated under reduced pres-
sure. The residue was purified by column chromatography (pen-
tane/ethyl acetate=97.5:2.5) to give the title compound as yellow
oil (114 mg, 31%). 1H NMR (500 MHz, CDCl3): d=7.73 (dd, J=1.5,
7.5 Hz, 1H), 7.41 (d, J=8.0 Hz, 1H), 7.15–7.28 (several peaks, 4H),
6.79 (m, 1H), 6.71 (dd, J=1.0, 9.0 Hz, 2H), 4.39 (d, J=5.0 Hz, 2H),
3.90 (t, J=5.0 Hz, 1H), 2.91 (t, J=9.0 Hz, 2H), 1.83 (m, 2H), 1.47 (m,
2H), 0.98 ppm (t, J=7.0 Hz, 3H). 13C NMR (125 MHz, CDCl3): d=
147.5, 142.4, 136.5, 129.1, 128.3, 128.0, 127.2, 118.0, 116.7, 113.2,
52.4, 33.5, 25.2, 13.4, 7.9 ppm. 125Te NMR (126 MHz, CDCl3): d=
408 ppm. HRMS (TOF MS EI+) m/z calcd for C17H21NTe [M]+:
369.0736. Found: 369.0743.
N1,N4-Di-tert-butyloxycarbonyl-N1,N4-bis(2-bromophenyl)butane-
1,4-diamine (16): To a solution of N-Boc-2-bromoaniline (2.36 g,
8.67 mmol) in anhydrous THF (60 mL), sodium hydride (60%wt.,
586 mg, 24.5 mmol) was added at 08C under nitrogen. The solu-
tion was stirred for 1 h at room temperature before the addition of
1,4-dibromobutane (0.52 mL, 4.33 mmol) at 08C. After being
heated at reflux for 38 h, the solution was quenched with water
(30 mL) and extracted with diethyl ether (40 mLꢀ3). The organic
layer was dried over magnesium sulfate, filtered and evaporated
under reduced pressure. The mixture was purified by flash column
2-(Diethoxymethyl)phenyl hexadecyl telluride (18b): To a solution
of 1-bromo-2-(diethoxymethyl)benzene (777 mg, 3.0 mmol) in an-
hydrous THF (20 mL) at ꢀ788C under nitrogen was added tert-
butyl lithium (1.7m, 3.5 mL, 6.0 mmol). The solution was stirred for
2 h at ꢀ788C prior to the addition of freshly ground tellurium
powder (383 mg, 3.0 mmol). After being stirred for 2 h at ambient
temperature, the solution was quenched with a saturated ammoni-
um chloride solution (20 mL) and extracted with diethyl ether
(20 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The crude prod-
uct was dissolved in ethanol (25 mL) followed by addition of
sodium borohydride (342 mg, 9.0 mmol) at ambient temperature
under nitrogen. After being stirred for 15 min, 1-bromohexadecane
(0.9 mL, 3.0 mmol) was added and the solution was allowed to stir
overnight. The reaction was quenched with water (20 mL) and ex-
tracted with diethyl ether (25 mLꢀ3). The organic layer was dried
over magnesium sulfate, filtered and evaporated under reduced
pressure. The residue was purified by column chromatography
(pentane/ethyl acetate=98:2) to give the title compound as
1
a yellow oil (935 mg, 59%). H NMR (400 MHz, CDCl3): d=7.63 (dd,
J=1.2, 8.0 Hz, 1H), 7.58 (dd, J=1.2, 8.0 Hz, 1H), 7.23 (m, 1H), 7.15
(m, 1H), 5.45 (s, 1H), 3.58 (m, 4H), 2.83 (t, J=7.6 Hz, 2H), 1.80 (m,
2H), 1.23–1.38 (several peaks, 32H), 0.88 ppm (t, J=6.8 Hz, 3H).
13C NMR (100 MHz, CDCl3): d=141.6, 135.6, 128.7, 126.8, 126.5,
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
10
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
115.8, 103.4, 61.3, 32.2, 31.9, 31.4, 29.7 (2C), 29.6 (2C), 29.5, 29.4,
29.0, 22.7, 15.3, 14.1, 8.2 ppm. 125Te NMR (126 MHz, CDCl3): d=
411 ppm. HRMS (TOF MS EI+) m/z calcd for C27H48O2Te [M]+:
534.2717. Found: 534.2706.
8.5 ppm. 125Te NMR (126 MHz, CDCl3): d=404, 284 ppm. HRMS
(TOF MS EI+) m/z calcd for C45H77NTe2 [M]+: 891.4181. Found:
891.4160.
2,2’-Dibromodiphenylamine (21): To a solution of 2-bromoaniline
(1.7 g, 10 mmol) in DMSO (20 mL) were added 2-bromocyclohex-2-
en-1-one (2.3 g, 13.2 mmol), iodine (1.3 g, 5 mmol) and p-toluensul-
fonic acid (188 mg, 1.1 mmol) at room temperature under nitro-
gen. After being stirred at 908C, overnight, the reaction was
quenched with sodium thiosulfate (100 mL 20% aq.) and extracted
with dichloromethane (100 mLꢀ3). The organic layer was dried
over magnesium sulfate, filtered and evaporated under reduced
pressure. The mixture was purified by flash column chromatogra-
phy (pentane/ethyl acetate=99:1) as eluent to give the title com-
2-(Hexadecyltelluro)benzaldehyde (19b): To 18b (880 mg,
1.65 mmol) in a round-bottom flask was added concentrated HCl
(0.68 mL). After being stirred for 15 min at room temperature, the
solution was quenched with a saturated sodium hydrogen carbon-
ate solution (10 mL) and extracted with diethyl ether (10 mLꢀ3).
The organic layer was dried over magnesium sulfate, filtered and
evaporated under reduce pressure. The residue was purified by
column chromatography (pentane/ethyl acetate=98:2) to give the
title compound as a yellow powder (739 mg, 98%). M.p. 56–588C.
1H NMR (400 MHz, CDCl3): d=10.14 (s, 1H), 7.82 (dd, J=1.6, 6.8 Hz,
1H), 7.67 (d, J=7.6 Hz, 1H), 7.37–7.41 (several peaks, 2H), 2.79 (t,
J=8.0 Hz, 2H), 1.84 (m, 2H), 1.26–1.48 (several peaks, 26H),
0.8 ppm (t, J=6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): d=192.8,
136.9, 136.7, 133.4, 132.7, 125.5, 123.2, 32.4, 31.9, 30.2, 29.6 (3C),
29.5, 29.3, 29.0, 22.6, 14.1, 6.7 ppm. 125Te NMR (126 MHz, CDCl3):
d=560 ppm. HRMS (TOF MS EI+) m/z calcd for C23H38OTe [M]+:
460.1985. Found: 460.1984.
1
pound as a pale yellow oil (1.3 g, 40%). H NMR (500 MHz, CDCl3):
d=7.59 (dd, J=1.0, 8.0 Hz, 2H), 7.30 (dd, J=1.5, 8.5 Hz, 2H), 7.20
(m, 2H), 6.85 (m, 2H), 6.45 ppm (s, 2H). 13C NMR (125 MHz, CDCl3):
d=140.0, 133.2, 128.1, 122.5, 117.9, 114.2 ppm. The 1H NMR data
were in accord with reported data in the literature.[32]
2,2’-Di(hexadecyltelluro)diphenylamine (22): Compound 20
(327 mg, 1.0 mmol), tert-butyl lithium (1.7m, 2.9 mL, 5.0 mmol),
freshly ground tellurium powder (508 mg, 4.0 mmol), sodium boro-
hydride (380 mg, 10 mmol) and 1-bromohexadecane (0.6 mL,
2.0 mmol) were reacted according to the general procedure to
give the title compound as a pale yellow solid (267 mg, 15%). M.p.
66–698C. 1H NMR (300 MHz, CDCl3): d=7.79 (dd, J=1.2, 7.8 Hz,
2H), 7.20 (m, 2H), 7.13 (dd, J=1.5, 8.1 Hz, 2H), 6.92 (s, 1H), 6.79
(m, 2H), 2.82 (t, J=7.5 Hz, 4H), 1.74 (m, 4H), 1.22–1.33 (several
peaks, 54H), 0.88 ppm (t, J=6.6 Hz, 6H). 13C NMR (75 MHz, CDCl3):
d=146.3, 140.8, 129.4, 122.3, 117.0, 106.9, 32.0, 31.9, 31.6, 29.7
(2C), 29.6, 29.5, 29.4, 28.9, 22.7, 14.1, 8.6 ppm. 125Te NMR (126 MHz,
CDCl3): d=337 ppm. HRMS (TOF MS EI+) m/z calcd for C44H75NTe2
[M]+: 877.4024. Found: 877.3997.
2-(Butyltelluro)-N-[2-(butyltelluro)benzyl]aniline (20a): To a solu-
tion of 2-(butyltelluro)benzaldehyde (224 mg, 0.77 mmol) and N-
Boc-2-(butyltelluro)aniline (235 mg, 0.85 mmol) in methanol (5 mL)
was added
a zinc chloride solution (0.5m in THF, 1.7 mL,
0.85 mmol) under nitrogen. After being stirred for 1 h, sodium cya-
noborohydride (54 mg, 0.85 mmol) was added and the solution
was allowed to stir overnight. The reaction was quenched with
water (10 mL) and extracted with diethyl ether (20 mLꢀ3). The or-
ganic layer was dried over magnesium sulfate, filtered and evapo-
rated under reduced pressure. The residue was purified by column
chromatography (pentane/ethyl acetate=98:2) to give the title
1
compound as a yellow oil (76 mg, 18%). H NMR (400 MHz, CDCl3):
2-(Phenyltelluro)diphenylamine (23a): To a solution of 2-bromo-
diphenylamine (247 mg, 1.0 mmol) in anhydrous THF (10 mL) at
ꢀ788C under nitrogen was added tert-butyl lithium (1.7m, 1.8 mL,
3.0 mmol). The solution was stirred for 1 h at ꢀ788C prior to the
addition of diphenyl ditelluride (409 mg, 1.0 mmol). After being
stirred, overnight, at ambient temperature, the solution was
quenched with a saturated ammonium chloride solution (20 mL)
and extracted with diethyl ether (20 mLꢀ3). The organic layer was
dried over magnesium sulfate, filtered and evaporated under re-
duced pressure. The mixture was purified by flash column chroma-
tography (pentane/ethyl acetate=97.5:2.5) as eluent to give the
title compound as a red oil (147 mg, 39%). 1H NMR (300 MHz,
CDCl3): d=7.76 (dd, J=1.2, 7.5 Hz, 1H), 7.65 (m, 2H), 7.19–7.31
(several peaks, 7H), 6.95–7.01 (several peaks, 3H), 6.81 (m, 1H),
6.23 ppm (s, 1H). 13C NMR (75 MHz, CDCl3): d=145.8, 143.0, 140.9,
137.0, 130.2, 129.6, 129.3, 127.8, 122.2, 121.8, 119.1, 116.7, 114.1,
108.7 ppm. 125Te NMR (126 MHz, CDCl3): d=552 ppm. HRMS (TOF
MS EI+) m/z calcd for C18H15NTe [M]+: 375.0267. Found: 375.0257.
d=7.80 (dd, J=1.6, 7.6 Hz, 1H), 7.70 (d, J=8.0 Hz, 1H), 7.36 (d, J=
7.2 Hz, 1H), 7.19–7.25 (several peaks, 2H), 7.13 (m, 1H), 6.63 (d, J=
8.4 Hz, 1H), 6.56 (m, 1H), 5.12 (s, 1H), 4.40 (s, 2H), 2.88 (t, J=
7.6 Hz, 2H), 2.77 (t, J=7.6 Hz, 2H), 1.79 (m, 2H), 1.70 (m, 2H), 1.31–
1.46 (several peaks, 4H), 0.85–0.94 ppm (several peaks, 6H).
13C NMR (100 MHz, CDCl3): d=149.9, 142.9, 142.4, 136.9, 130.6,
128.1, 128.0, 127.4, 118.3, 116.3, 109.7, 100.5, 52.9, 33.8, 33.6, 25.2,
24.9, 13.4 (2C), 8.60, 8.21 ppm. 125Te NMR (126 MHz, CDCl3): d=403,
284 ppm. HRMS (TOF MS EI+) m/z calcd for C21H29NTe2 [M]+:
555.0425. Found: 555.0408.
2-(Hexadecyltelluro)-N-2-(hexadecyltelluro)benzyl]aniline (20b):
To a solution of 19b (352 mg, 0.77 mmol) and 14b (380 mg,
0.85 mmol) in methanol (5 mL) was added zinc chloride solution
(0.5m in THF, 2 mL, 1.0 mmol) under nitrogen. After being stirred
for 1 h, sodium cyanoborohydride (54 mg, 0.85 mmol) was added
and the solution was allowed to stir overnight. The reaction was
quenched with water (10 mL) and extracted with diethyl ether
(20 mLꢀ3). The organic layer was dried over magnesium sulfate,
filtered and evaporated under reduced pressure. The residue was
purified by column chromatography (pentane/ethyl acetate=98:2)
to give the title compound as a yellow solid (280 mg, 41%). M.p.
49–518C. 1H NMR (400 MHz, CDCl3): d=7.80 (dd, J=1.6, 7.6 Hz,
1H), 7.70 (dd, J=1.2, 7.6 Hz, 1H), 7.36 (dd, J=1.2, 8.0 Hz, 1H),
7.18–7.25 (several peaks, 2H), 7.12 (m, 1H), 6.63 (dd, J=0.8, 8.0 Hz,
1H), 6.56 (m, 1H), 5.11 (t, J=5.6 Hz, 1H), 4.40 (d, J=5.6 Hz, 2H),
2.88 (t, J=7.6 Hz, 2H), 2.76 (t, J=7.6 Hz, 2H), 1.80 (m, 2H), 1.75 (m,
2H), 1.28–1.45 (several peaks, 52H), 0.90 ppm (t, J=7.2 Hz, 6H).
13C NMR (100 MHz, CDCl3): d=149.9, 142.9, 142.4, 136.9, 130.6,
128.1, 128.0, 127.4, 118.3, 116.4, 109.7, 100.5, 52.9, 32.2, 31.9 (2C),
31.7, 31.5, 29.7 (2C), 29.6, 29.5, 29.4, 29.0, 28.9, 22.7, 14.1, 8.9,
2-(4-Methoxyphenyltelluro)diphenylamine (23b): To a solution of
2-bromodiphenylamine (247 mg, 1.0 mmol) in anhydrous THF
(10 mL) at ꢀ788C under nitrogen was added tert-butyl lithium
(1.7m, 1.8 mL, 10.0 mmol). The solution was stirred for 2 h at
ꢀ788C prior to the addition of bis(4-methoxyphenyl)ditelluride
(469 mg, 1.0 mmol). After being stirred, overnight, at ambient tem-
perature, the solution was quenched with a saturated ammonium
chloride solution (20 mL) and extracted with diethyl ether (20 mLꢀ
3). The organic layer was dried over magnesium sulfate, filtered
and evaporated under reduced pressure. The mixture was purified
by flash column chromatography (pentane/ethyl acetate=97.5:2.5)
as eluent to give the title compound as a pale yellow solid
1
(168 mg, 42%). M.p. 57–598C. H NMR (400 MHz, CDCl3): d=7.62–
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
11
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
7.65 (several peaks, 2H), 7.56 (dd, J=1.2, 8.0 Hz, 1H), 7.16–7.25
(several peaks, 4H), 6.90–6.94 (several peaks, 3H), 6.75–6.79 (sever-
al peaks, 3H), 6.03 (s, 1H), 3.78 ppm (s, 3H). 13C NMR (100 MHz,
CDCl3): d=160.0, 145.1, 143.4, 140.3, 139.1, 129.4, 129.3, 122.9,
121.4, 118.4, 118.0, 115.7, 111.1, 102.6, 55.2 ppm. 125Te NMR
(126 MHz, CDCl3): d=554 ppm. HRMS (TOF MS EI+) m/z calcd for
C19H17NOTe [M]+: 405.0372. Found: 405.0360.
HPLC peroxidation assay
The experimental setup for recording inhibited rates of peroxida-
tion (Rinh) and inhibition times (Tinh) during azo-initiated peroxida-
tion of linoleic acid in a two-phase chlorobenzene-water system
has been recently described.[33] The values of Rinh and Tinh reported
in the presence of NAC are means ꢁSD based on triplicates. As
Rinh and Tinh values show slight variations depending on the
amount of linoleic acid hydroperoxide which is always present in
commercial samples as an impurity, and increases upon storage,
the procedure is standardized in the following way. To a newly re-
ceived sample of linoleic acid was added small amounts of peroxi-
dized linoleic acid from an older bottle until the concentration, as
assessed by UV spectroscopy of conjugated diene at 234 nm, was
about 175 mm.
2-(4-Trifluoromethylphenyl)diphenylamine (23c): To a solution of
2-bromodiphenylamine (247 mg, 1.0 mmol) in anhydrous THF
(10 mL) at ꢀ788C under nitrogen was added tert-butyl lithium
(1.7m, 1.8 mL, 3.0 mmol). The solution was stirred for 2 h at ꢀ788C
prior to the addition of bis(4-trifluoromethylphenyl)ditelluride
(545 mg, 1.0 mmol). After being stirred, overnight, at ambient tem-
perature, the solution was quenched with a saturated ammonium
chloride solution (20 mL) and extracted with diethyl ether (20 mLꢀ
3). The organic layer was dried over magnesium sulfate, filtered
and evaporated under reduced pressure. The mixture was purified
by flash column chromatography (pentane/ethyl acetate=97.5:2.5)
as eluent to give the title compound as a red solid (201 mg, 46%).
NAC consumption assay
The concentration of NAC in the aqueous phase of the two-phase
system during ongoing peroxidation was determined by using the
assay of Means,[34] with slight modifications. Every 30 min during
the first 3 h of peroxidation, 20 mL of the aqueous phase was with-
drawn by syringe and injected into a UV cuvette containing 1 mL
of a 0.25m solution of Aldrithiol-4 in water/DMF (49:1). The con-
centration of pyridin-4-thiol was determined spectrophotometrical-
ly at 324 nm in comparison with a standard curve. The rate of NAC
consumption was calculated by least-square methods from time/
concentration plots.
1
M.p. 76–798C. H NMR (400 MHz, CDCl3): d=7.86 (m, 1H), 7.64 (dd,
J=0.8, 8.4 Hz, 2H), 7.42 (dd, J=0.8, 8.4 Hz, 2H), 7.28–7.35 (several
peaks, 4H), 7.02–7.06 (several peaks, 3H), 6.91 (m, 1H), 6.34 ppm
(s, 1H). 13C NMR (125 MHz, CDCl3): d=146.3, 142.5, 142.1, 135.7,
131.0, 129.6 (q, JCF =32 Hz), 129.3, 125.9 (q, JCF =4 Hz), 124.0 (q,
J
CF =270 Hz), 122.3, 122.1, 120.3, 119.5, 116.3, 107.0 ppm. 125Te NMR
(126 MHz, CDCl3): d=551 ppm. 19F NMR (376 MHz, CDCl3): d=
ꢀ63 ppm. HRMS (TOF MS EI+) m/z calcd for C19H14F3NTe [M]+:
443.0141. Found: 443.0138.
N-Methyl-N-2-(ocyltelluro)phenyl-O-propylhydroxylamine (24):
To a solution of N-(2-bromophenyl)-N-methyl-O-propylhydroxyl-
amine (355 g, 1.5 mmol) in anhydrous THF (10 mL) at ꢀ788C under
nitrogen was added n-butyl lithium (1.6m, 1.1 mL, 1.74 mmol). The
solution was stirred for 1.5 h at ꢀ788C prior to the addition of di-
octyl ditelluride (698 mg, 1.5 mmol). After being stirred, overnight,
at ambient temperature, the solution was quenched with a saturat-
ed ammonium chloride solution (20 mL) and extracted with diethyl
ether (20 mLꢀ3). The organic layer was dried over magnesium sul-
fate, filtered and evaporated under reduced pressure. The mixture
was purified by flash column chromatography (pentane/ethyl ace-
tate=98:2) as eluent to give the title compound as pale a yellow
oil (255 mg, 63%). 1H NMR (400 MHz, CDCl3): d=7.46 (dd, J=1.2,
7.6 Hz, 1H), 7.28 (dd, J=1.2, 7.2 Hz, 1H), 7.23 (m, 1H), 7.10 (m, 1H),
3.62 (t, J=6.4 Hz, 2H), 2.90 (s, 3H), 2.80 (t, J=7.6 Hz, 2H), 1.86 (m,
2H), 1.60 (m, 2H), 1.30–1.47 (several peaks, 10H), 0.87–0.92 ppm
(several peaks, 6H).13C NMR (100 MHz, CDCl3): d=153.9, 131.1,
127.4, 127.1, 121.1, 114.4, 74.2, 47.2, 32.4, 31.8, 31.1, 29.1, 29.0,
22.6, 21.9, 14.0, 10.5, 5.1 ppm. 125Te NMR (126 MHz, CDCl3): d=
395 ppm. HRMS (TOF MS EI+) m/z calcd for C18H31NOTe [M]+:
407.1468. Found: 407.1463.
Acknowledgements
The Swedish Research Council (grant 621-2011-4006) is grate-
fully acknowledged. We also thank the COST-action CM1201
(Biomimetic Radical Chemistry) for financial support.
Keywords: antioxidants · amines · chain-breaking activity ·
organotellurium · regenerable
[1] G. W. Burton, K. U. Ingold, Acc. Chem. Res. 1986, 19, 194–201.
[2] J. J. Hanthorn, L. Valgimigli, D. A. Pratt, J. Am. Chem. Soc. 2012, 134,
8306–8309.
[3] J. A. Howard, K. U. Ingold, Can. J. Chem. 1963, 41, 1744–1751.
[4] K. U. Ingold, G. W. Burton, D. O. Foster, M. Zuker, L. Hughes, S. Lacelle, E.
Lusztyk, M. Slaby, FEBS Lett. 1986, 205, 117–120.
[5] K. U. Ingold, D. A. Pratt, Chem. Rev. 2014, 114, 9022–9046.
[6] L. Valgimigli, D. A. Pratt, Acc. Chem. Res. 2015, 48, 966–975.
[7] M. Wijtmans, D. A. Pratt, L. Valgimigli, G. A. DiLabio, G. F. Pedulli, N.
Porter, Angew. Chem. Int. Ed. 2003, 42, 4370–4373; Angew. Chem. 2003,
115, 4506–4509.
[8] a) T. Nam, C. L. Rector, H. Kim, A. F.-P. Sonnen, R. Meyer, W. M. Nau, J. At-
kinson, J. Rintoul, D. A. Pratt, N. A. Porter, J. Am. Chem. Soc. 2007, 129,
10211–10219.
[9] B. Li, J. R. Harjani, N. S. Cormier, H. Madarati, G. Cosa, D. A. Pratt, J. Am.
Chem. Soc. 2013, 135, 1394–1405.
[10] a) S. Kumar, H. Johansson, T. Kanda, L. Engman, T. Mꢂller, M. Jonsson,
G. F. Pedulli, S. Petrucci, L. Valgimigli, Org. Lett. 2008, 10, 4895–4898;
b) S. Kumar, H. Johansson, T. Kanda, L. Engman, T. Mꢂller, H. Bergenudd,
M. Jonsson, G. F. Pedulli, R. Amorati, L. Valgimigli, J. Org. Chem. 2010,
75, 716–725; c) H. Johansson, D. Shanks, L. Engman, R. Amorati, G. F.
Pedulli, L. Valgimigli, J. Org. Chem. 2010, 75, 7535–7541; d) V. P. Singh,
J. Poon, L. Engman, J. Org. Chem. 2013, 78, 1478–1487; e) J. Poon, V. P.
Singh, L. Engman, J. Org. Chem. 2013, 78, 6008–6015; f) V. P. Singh, J.
Poon, L. Engman, Org. Lett. 2013, 15, 6274–6277; g) J. Poon, V. P. Singh,
J. Yan, L. Engman, Chem. Eur. J. 2015, 21, 2447–2457.
N,N-Dimethyl-2-(octyltelluro)aniline (25): 2-Bromo-N,N-dimethyl-
aniline (200 mg, 1.0 mmol), tert-butyl lithium (1.7m, 1.2 mL,
2.0 mmol), freshly ground tellurium powder (128 mg, 1.0 mmol),
sodium borohydride (190 mg, 5.0 mmol) and 1-bromooctane
(0.2 mL, 1.0 mmol) were reacted according to the general proce-
dure to give the title compound as a yellow oil (317 mg, 88%).
1H NMR (500 MHz, CDCl3): d=7.32 (d, J=7.5 Hz, 1H), 7.19 (m, 1H),
7.13 (dd, J=1.0, 8.0 Hz, 1H), 7.05 (m, 1H), 2.76 (t, J=7.5 Hz, 2H),
2.69 (s, 6H), 1.86 (m, 2H), 1.29–1.47 (several peaks, 10H), 0.90 ppm
(t, J=7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): d=155.1, 131.8, 126.8,
126.2, 120.6, 118.3, 45.4, 32.5, 31.8, 31.2, 29.1, 29.0, 22.6, 14.1,
4.8 ppm. 125Te NMR (126 MHz, CDCl3): d=398 ppm. HRMS (TOF MS
EI+) m/z calcd for C16H27NTe [M]+: 363.1206. Found: 363.1212.
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
12
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Paper
[11] R. Amorati, L. Valgimigli, P. Dinꢃr, K. Bakhtiari, M. Saeedi, L. Engman,
Chem. Eur. J. 2013, 19, 7510–7522.
[23] M. T. Barros, S. S. Dey, C. D. Maycock, P. Rodriques, Chem. Commun.
2012, 48, 10901–10903.
[24] Y. Aso, H. Yamashita, T. Otsubo, F. Ogura, J. Org. Chem. 1989, 54, 5627–
5629.
[12] M. Mbuyi, M. Evers, G. Tihange, A. Luxen, L. Christiaens, Tetrahedron
Lett. 1983, 24, 5873–5876.
[25] K. Lederer, Ber. Dtsch. Chem. Ges. 1915, 48, 2049.
[26] L. Engman, J. Persson, J. Organomet. Chem. 1990, 388, 71–74.
[27] J. Sisko, S. M. Weinreb, Synth. Commun. 1988, 18, 1035–1042.
[28] F. Colobert, V. Valdivia, S. Choppin, F. R. Leroux, I. Fernꢄndez, E. ꢅlvarez,
N. Khiar, Org. Lett. 2009, 11, 5130–5133.
[29] K. Chen, S. A. Pullarkat, Org. Biomol. Chem. 2012, 10, 6600–6606.
[30] Y. Khalid, N. I. Al-Salim, M. Greaves, W. R. McWhinnie, A. A. West, J.
Chem. Soc. Dalton Trans. 1989, 9, 1697–1703.
[31] A. Minatti, S. L. Buchwald, Org. Lett. 2008, 10, 2721–2724.
[32] L. Liang, P. Chien, J. Lin, M. Huang, Y. Huang, J. Liao, Organometallics
2006, 25, 1399–1411.
[33] D. Shanks, R. Amorati, M. G. Fumo, G. F. Pedulli, L. Valgimigli, L. Engman,
J. Org. Chem. 2006, 71, 1033–1038.
[13] I. D. Sadekov, A. A. Maksimenko, G. M. Abakarov, S. S. Gasanov, V. A.
Pantin, V. I. Minkin, Mendeleev Commun. 1993, 3, 53–54.
[14] W. M. Seganish, P. J. DeShong, J. Org. Chem. 2004, 69, 6790–6795.
[15] P. Beak, W. Lee, Tetrahedron Lett. 1989, 30, 1197–1200.
[16] Y. You, K. Ahsan, M. R. Detty, J. Am. Chem. Soc. 2003, 125, 4918–4927.
[17] R. K. Jensen, S. Korcek, M. Zinbo, J. L. Gerlock, J. Org. Chem. 1995, 60,
5396–5400.
[18] E. A. Haidasz, R. Shah, D. A. Pratt, J. Am. Chem. Soc. 2014, 136, 16643–
16650.
[19] R. Shah, E. A. Haidasz, L. Valgimigli, D. A. Pratt, J. Am. Chem. Soc. 2015,
137, 2440–2443.
[20] L. Engman, M. P. Cava, Synth. Commun. 1982, 12, 163–165.
[21] Y. Li, L. C. Silverton, R. Haasch, Y. Y. Tong, Langmuir 2008, 24, 7048–
7053.
[34] M. Le, G. E. Means, Anal. Biochem. 1995, 229, 264–271.
[22] T. Nakamura, T. Miyamae, I. Nakai, H. Kondoh, T. Kawamoto, N. Kobaya-
shi, S. Yasuda, D. Yoshimura, T. Ohta, H. Nozoye, M. Matsumoto, Lang-
muir 2005, 21, 3344–3353.
Received: May 18, 2016
Published online on && &&, 0000
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
13
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Full Paper
FULL PAPER
Te time: Aromatic amines carrying alkyl-
telluro groups quench lipidperoxyl radi-
cals more efficiently than a-tocopherol
in chlorobenzene and are regenerable
by aqueous-phase N-acetylcysteine. Ac-
cording to the proposed mechanism
(see scheme), the compounds are multi-
functional in the sense that they, at the
same time, are both chain-breaking and
hydroperoxide decomposing.
&
Catalytic Antioxidants
J.-f. Poon, J. Yan, V. P. Singh, P. J. Gates,
L. Engman*
&& – &&
Alkyltelluro Substitution Improves the
Radical-Trapping Capacity of Aromatic
Amines
&
&
Chem. Eur. J. 2016, 22, 1 – 14
www.chemeurj.org
14
ꢁ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!