Lewis base-catalyzed reaction of aziridinofullerene with ureas for the preparation of fulleroimidazolidinones

Article abstract of DOI:10.1021/jo5022772

The Lewis base-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with various ureas allows the easy preparation of fulleroimidazolidinones with a high tolerance for functional groups. Alkyl-substituted ureas show better reactivity than aryl-substituted ureas.

Full text of DOI:10.1021/jo5022772

Note
pubs.acs.org/joc
Lewis Base-Catalyzed Reaction of Aziridinofullerene with Ureas for
the Preparation of Fulleroimidazolidinones
Meng-Lei Xing,† Xin-Wei Lu, Chun-Bao Miao,† Jia-Xing Li,‡ Xiao-Qiang Sun,† and Hai-Tao Yang*,†
†School of Petrochemical Engineering, Changzhou University, Changzhou 213164, China
‡Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei
230031, China
S
* Supporting Information
ABSTRACT: The Lewis base-catalyzed double nucleophilic
substitution reaction of N-tosylaziridinofullerene with various
ureas allows the easy preparation of fulleroimidazolidinones with
a high tolerance for functional groups. Alkyl-substituted ureas
show better reactivity than aryl-substituted ureas.
unctionalization on the sphere of C60 and investigation of
the 1,3-dipolar cycloaddition reaction is one of the most widely
Fthe properties of these new generated fullerene derivatives used methods to construct five-membered-ring-fused C60
derivatives,7a it is incapable of preparing these derivatives.
for their applications in materials science and medicinal
They have been mainly synthesized through metal-catalyzed or
-promoted radical reaction of C60 with different reactants. In
case of the C60-fused imidazolidinones, only the Minakata
group reported a PCy3-catalyzed formal [3 + 2] reaction of N-
sulfonylated aziridinofullerene with aryl isocyanates for their
preparation (Scheme 1).3 However, the substrates were limited
chemistry constitute an important research field in fullerene
chemistry. Although a large number of functionalization
protocols have emerged,1 there is still a requirement to seek
new and efficient methods for the preparation of organo-
fullerenes with novel architectures. In the past few years, the
Itami and Minakata groups pioneered the use of N-
tosylaziridinofullerene as a versatile platform for functionaliza-
tion of fullerenes by means of acid-catalyzed double
nucleophilic substitution reactions accompanied by the loss of
sulfonamide.2 Later, the formal [3 + 2] reactions of N-
tosylaziridinofullerene with CO2, isocyanates,3 and carbonyls4
were developed. We also explored the reaction of N-
tosylaziridinofullerene with sulfamides or amidines for the
easy preparation of C60-fused cyclic diaminated fullerenes.5
C60 has been the most striking electron-acceptor because of
its high electron affinity and low reorganization energies for
electron transfer.6 The design and synthesis of new fullerene
derivatives with improved electron affinity is a very appealing
task in the search of their applications in materials science.
However, the addition of most addends to C60 leads to a
decrease in their electron-acceptor properties as a result of the
change in the hybridization of carbon from sp2 to a less
electronegative sp3 state.7 In order to increase the electron-
acceptor character of fullerene derivatives, one strategy is to
link electronegative atoms directly to the C60 core.8 C60-fused
dioxolanes,9 dioxaborolanes,10 oxazolines,11 oxazolidines,4
oxazolidinones,12 imidazolines,11e,13 and imidazolidinones,3 in
which two electronegative atoms are directly attached to the
C60 core, precisely meet the requirement. Most recently, we
developed a hypervalent iodine reagent-promoted intermolec-
ular diamination reaction of C60 with sulfamides/phosphoryl
diamides for the synthesis of two classes of novel C60-fused
cyclic sulfamide/phosphoryl diamide derivatives.14 Although
Scheme 1
to aryl isocyanates, and alkyl-substituted C60-fused imidazolidi-
nones could not be obtained. Although intramolecular
diamination of olefins with ureas has been a suitable approach
to generate bicyclic heterocycles with two nitrogen atoms,15
C60-fused imidazolidinones have never been synthesized
directly from C60 and ureas, partially because of the
unfavorability of intermolecular reactions.
Recently we have been interested in the development of new
routes to cyclic diaminated [60]fullerenes starting from N-
tosylaziridinofullerene.5 The reaction conditions were found to
vary greatly with different diamine sources. The reaction of
sulfamides with N-tosylaziridinofullerene could be accom-
plished well using BF3·Et2O as the catalyst. However, in the
Received: October 5, 2014
© XXXX American Chemical Society
A
dx.doi.org/10.1021/jo5022772 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
reaction of amidines with N-tosylaziridinofullerene, Lewis acids
showed no catalytic activity. On the contrary, a Lewis base was
found to be an efficient catalyst. Furthermore, the substituents
on the nitrogen atom had great influence on the reaction.
Therefore, the reactivity of N-tosylaziridinofullerene needed to
be further investigated in order to gain insight into its essence.
In continuation of our interest in the chemical functionalization
of C60,4,5,11d,e,14,16 here we report an interesting transformation
employing ureas as the diamine source for the easy preparation
of C60-fused imidazolidinones (Scheme 1).
temperature to 90 °C led to lower yield and longer reaction
time (Table 1, entry 8). Eventually, a 1:3a:NMI molar ratio of
1:2:1 and a reaction temperature of 120 °C were selected as the
optimized conditions for subsequent investigation of the double
nucleophlic substitution of 1 with different ureas (Table 2).
Table 2. Substrate Scope of the N-Methylimidazole-
Catalyzed Reaction of Aziridinofullerene 1 with N-Tosyl-N′-
alkylureas 3
N,N′-Dibutylurea was first selected as a substrate to try the
possibility (Scheme 2). To our disappointment, with either
Scheme 2
BF3·Et2O or DMAP, which have been proved to be efficient
catalysts for the double nucleophilic substitution reaction of N-
sulfonylated aziridinofullerenes,2a,5 no desired fulleroimidazoli-
dinone product was obtained. In the presence of 5 equiv of BF3·
Et2O, most of the aziridinofullerene was transformed to C60.
With DMAP, isomerization of N-tosylaziridinofullerene (1) to
azafulleroid 2 (48%) occurred along with little conversion to
C60 after stirring at 120 °C for 6 h.
When one of the butyl groups was replaced by a tosyl group,
although BF3·Et2O still showed no catalytic activity, DMAP
afforded the anticipated product 4a in 76% yield along with
small amounts of azafulleroid 2 and C60 (Table 1, entries 1 and
Table 1. Screening of the Reaction Conditions
Except for 3c, all of the ureas 3a−h with a tosyl group on one
nitrogen atom and an alkyl group on the other gave good yields
of fulleroimidazolidinones 4 (Table 2). Sterically hindered
amine 3c needed a longer reaction time and afforded the
product in lower yield (Table 2, entry 3). Especially, this
reaction showed superb functional group tolerance. Ester,
alkenyl, alkynyl, acetal, and phenolic hydroxyl groups had no
influence on the reaction (Table 2, entries 4−8). The
introduction of these groups allows further transformations
with other reactants, which is important for investigating the
applications of this class of compounds with different functional
addends. It is worth noting that present method is a good
complement to Minakata’s method,3 which cannot be used to
prepare fulleroimidazolidinones with an alkyl group on the
nitrogen atom.
The reactivity of ureas 3i−l linked with an aryl group was
also investigated (Table 3). For substrate 3i, using NMI as the
base gave a very low conversion to 4i as detected by TLC,
probably because of the lower nucleophilicity of the aryl amine
compared with alkyl amines. Replacing NMI by DMAP
afforded the desired product 4i in 47% yield because DMAP
entry
catalyst
molar ratio
T (°C)
time (h)
yield (%)
1
2
3
4
5
6
7
8
BF3·Et2O
Sn(OTf)2
Sc(OTf)3
DMAP
1:2:5
1:2:1
1:2:1
1:2:0.2
1:2:1
1:2:1
1:2:1
1:2:1
rt
2
12
12
8
0
20
15
76
17
83
84
70
120
120
120
120
120
120
90
2,6-lutidine
DABCO
NMI
12
11
7
NMI
12
4). Other Lewis acids such as Sn(OTf)2 and Sc(OTf)3
exhibited low catalytic activity (Table 1, entries 2 and 3).
The organic bases DABCO and N-methylimidazole (NMI)
gave better results than DMAP because only a trace of
azafulleroid 2 was observed (Table 1, entries 6 and 7). In
contrast to DABCO, NMI provided a comparative yield within
a shorter reaction time. 2,6-Lutidine furnished only a 17% yield
of the product (Table 1, entry 5). Reducing the reaction
B
dx.doi.org/10.1021/jo5022772 | J. Org. Chem. XXXX, XXX, XXX−XXX

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Table 3. DMAP-Catalyzed Reaction of Aziridinofullerene 1
with N-Tosyl-N′-arylureas
Scheme 3. Reaction of N-Tosylaziridinofullerene 1 with
Benzoyl- and Ethoxycarbonyl-Substituted Ureas 5
has a stronger basicity than NMI.17 An electron-donating or
-withdrawing group on the phenyl ring did not show obvious
differences. A naphthyl group also provided the product 4l in
49% yield. Overall, aromatic substituents on the nitrogen atom
gave worse results than alkyl substituents.
We next studied the applicability of ureas with different
sulfonyl substituents in this reaction (Table 4). 4-Methox-
ybenzenesulfonyl, 4-nitrobenzenesulfonyl, and methylsulfonyl
all worked well to give the corresponding products 4m−o in
excellent yields.
The benzoyl group gave results similar to those for the sulfonyl
group. Ureas 5a and 5b connected to either an alkyl group or
an aryl group, respectively, reacted with 1 to provide the
desired products 6a (68%) and 6b (36%), although a larger
amount of base and longer reaction times were needed.
Unfortunately, the ethoxycarbonyl-substituted urea 5c failed to
give the product 6c with either NMI or DMAP, probably
because of the weaker acidity of the N−H in 5c than in 5a and
5b.
The known products 4i−l were confirmed through
comparison of their spectral data to those reported in the
literature.3 All of the new compounds 4a−h, 4m−o, 6a, and 6b
Table 4. Study of the Reaction Scope by Variation of the
Sulfonyl Group on the Urea
1
were unambiguously characterized by their HRMS, H NMR,
13C NMR, and UV−vis spectra (see the Supporting
Information).
In summary, a new method for the synthesis of full-
eroimidazolidinones via a Lewis base-catalyzed double
nucleophilic reaction of N-tosylaziridinofullerene with ureas
has been developed. This method shows a high degree of
functional group tolerance. The influence of the substituent
linked with the nitrogen atom on the reaction was investigated
carefully. The exploration of the reactivity of N-tosylaziridino-
fullerene for the preparation of not easily available fullerene
derivatives is ongoing in our laboratory.
EXPERIMENTAL SECTION
■
Preparation of the Starting Materials. Compounds 3a−l were
prepared from tosyl isocyanate and the corresponding amines.18
Compounds 3m−o were prepared from butyl isocyanate and the
correspongding sulfonamides catalyzed by CuCl.19 Compounds 5a
and 5b were synthesized according to the method described in the
literature.20
As can be seen from the above results, the sulfonyl group was
indispensable to the success of the reaction. This could be
explained by the fact that the electron-withdrawing character of
the sulfonyl group enhances the adicity of the N−H, which is
beneficial to the formation of a more nuceophilic nitrogen
anion under basic conditions. To further investigate the effect
of other electron-withdrawing groups such as benzoyl and
ethoxycarbonyl, we prepared ureas 5a−c and treated them with
aziridinofullerene 1 under the standard conditions (Scheme 3).
Preparation of 5c. Ethoxycarbonyl isocyanate (460 mg, 4 mmol)
was added slowly to a solution of benzylamine (514 mg, 4.8 mmol) in
dichloromethane (10 mL) in an ice bath with magnetic stirring. After
completion of the addition, the mixture was allowed to warm to room
temperature and stirred for 1 h. Dichloromethane (30 mL) was added,
and the mixture was washed with 1 mol/L hydrochloric acid (2 × 10
mL) and saturated sodium bicarbonate (10 mL). The organic layer
C
dx.doi.org/10.1021/jo5022772 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
was dried with anhydrous Na2SO4. Removal of the solvent and
recrystallization of the residue with ethanol afforded the final product
5c (480 mg, 54%).
4e (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.10 (d, J = 8.3 Hz, 2H), 7.40 (d, J = 8.1 Hz, 2H), 6.08 (ddt, J = 17.1,
10.3, 6.0 Hz, 1H), 5.32 (dd, J = 17.1, 1.0 Hz, 1H), 5.25 (dd, J = 10.2,
1.0 Hz, 1H), 4.70 (d, J = 6.0 Hz, 2H), 2.52 (s, 3H); 13C NMR (125
MHz, CDCl3/CS2) δ 152.05 (CO), 148.12, 148.04, 146.82, 146.61,
146.60, 146.42, 146.33, 146.21, 146.08, 145.59, 145.25, 145.20, 145.17,
144.95, 144.84, 144.69, 144.42, 143.88, 142.98, 142.91, 142.85, 142.70,
142.21, 142.09, 142.04, 141.63, 141.35, 139.74, 138.46, 136.58, 136.54,
136.51, 132.90, 129.59, 128.97, 119.48, 79.93 (C(sp3) of C60), 79.04
(C(sp3) of C60), 45.45, 21.92; UV−vis (CHCl3) λmax/nm 256, 317,
417, 453, 682; HRMS (MALDI-TOF MS) m/z [M + H]+ calcd for
C71H13N2O3S 973.0647, found 973.0642.
5c (colorless solid, mp 104−105 °C): 1H NMR (300 MHz, CDCl3)
δ 8.12 (br, 1H), 7.23−7.38 (m, 5H), 7.08 (br, 1H), 4.50 (d, J = 5.8 Hz,
2H), 4.20 (q, J = 7.1 Hz, 2H), 1.30 (t, J = 7.1 Hz, 3H); 13C NMR (75
MHz, CDCl3) δ 154.53, 153.72, 138.24, 128.75, 127.67, 127.53, 62.38,
43.88, 14.35.
General Procedure for the Lewis Base-Catalyzed Reaction of
Aziridinofullerene 1 with Ureas. A mixture of aziridinofullerene 1
(17.8 mg, 0.02 mmol), urea 3a−o (0.04 mmol), and base (for 3a−h
and 3m−o, NMI (0.02 mmol, 50 μL of 0.4 mol/L NMI solution in
chlorobenzene); for 3i−l, DMAP (0.004 mmol, 40 μL of 0.1 mol/L
DMAP solution in chlorobenzene) in 3 mL of dry chlorobenzene was
stirred at 120 °C for the designated time until completion of the
reaction as determined by TLC. The solvent was removed in vacuo,
and the residue was purified on a silica gel column using CS2/toluene
as the eluent to give the product 4a−o (4a: 16.5 mg, 84%; 4b: 17.3
mg, 85%; 4c: 10.2 mg, 50%; 4d: 18.8 mg, 92%; 4e: 17.1 mg, 88%; 4f:
16.9 mg, 87%; 4g: 17.4 mg, 85%; 4h: 18.5 mg, 88%; 4i: 9.5 mg, 47%;
4j: 12.1 mg, 58%; 4k: 10.7 mg, 52%; 4l: 10.3 mg, 49%; 4m: 18.1 mg,
90%; 4n: 18.6 mg, 91%; 4o: 16 mg, 88%).
4f (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2) δ
8.10 (d, J = 8.3 Hz, 2H), 7.40 (d, J = 8.1 Hz, 2H), 4.87 (d, J = 2.5 Hz,
2H), 2.52 (s, 3H), 2.28 (t, J = 2.5 Hz, 1H); 13C NMR (125 MHz,
CDCl3/CS2) δ 151.56 (CO), 148.15, 148.04, 146.78, 146.64,
146.62, 146.43, 146.36, 146.23, 146.18, 145.56, 145.35, 145.26, 145.21,
144.72, 144.66, 144.45, 144.37, 143.96, 142.98, 142.93, 142.85, 142.68,
142.26, 142.16, 142.05, 141.55, 141.35, 139.75, 138.46, 136.68, 136.52,
136.35, 129.64, 129.05, 79.56 (C(sp3) of C60), 79.16 (C(sp3) of C60),
78.57, 74.67, 32.10, 21.93; UV−vis (CHCl3) λmax/nm 257, 318, 417,
453, 682; HRMS (MALDI-TOF MS) m/z [M + H]+ calcd for
C71H11N2O3S 971.0490, found 971.0484, [M + Na]+ calcd for
C71H10N2NaO3S 993.0310, found 993.0304.
4a (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.09 (d, J = 8.3 Hz, 2H), 7.39 (d, J = 8.1 Hz, 2H), 4.03 (t, J = 7.8 Hz,
2H), 2.51 (s, 3H), 1.93 (quint, J = 7.6 Hz, 2H), 1.46 (sextet, J = 7.3
Hz, 2H), 0.96 (t, J = 7.3 Hz, 3H); 13C NMR (125 MHz, CDCl3/CS2)
δ 152.23 (CO), 148.13, 148.05, 146.80, 146.61, 146.58, 146.42,
146.32, 146.20, 146.05, 145.60, 145.25, 145.19, 145.08, 144.98, 144.72,
144.41, 143.66, 142.98, 142.91, 142.87, 142.72, 142.16, 142.08, 142.03,
141.67, 141.37, 139.91, 138.44, 136.60, 136.55, 136.47, 129.56, 128.94,
79.99 (C(sp3) of C60), 79.01 (C(sp3) of C60), 43.16, 31.69, 21.91,
20.61, 13.99; UV−vis (CHCl3) λmax/nm 257, 319, 419, 453, 683;
HRMS (MALDI-TOF MS) m/z [M + H]+ calcd for C72H17N2O3S
989.0960, found 989.0954.
4g (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.09 (d, J = 8.3 Hz, 2H), 7.39 (d, J = 8.1 Hz, 2H), 4.95 (t, J = 5.4 Hz,
1H), 4.10 (d, J = 5.4 Hz, 2H), 3.42 (s, 6H), 2.51 (s, 3H); 13C NMR
(125 MHz, CDCl3/CS2) δ 152.81 (CO), 148.16, 148.05, 146.76,
146.61, 146.40, 146.33, 146.21, 146.01, 145.63, 145.24, 145.18, 145.16,
145.13, 144.81, 144.65, 144.49, 144.03, 142.96, 142.92, 142.85, 142.68,
142.27, 142.11, 142.00, 141.62, 141.35, 139.77, 138.37, 136.64, 136.53,
135.98, 129.57, 128.93, 102.42, 80.23 (C(sp3) of C60), 79.19 (C(sp3)
of C60), 55.16, 45.48, 21.91; UV−vis (CHCl3) λmax/nm 256, 318, 417,
453, 682; HRMS (MALDI-TOF MS) m/z [M + Na]+ calcd for
C72H16N2NaO5S 1043.0678, found 1043.0672.
4b (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.14 (d, J = 8.3 Hz, 2H), 7.42 (d, J = 8.2 Hz, 2H), 7.40 (d, J = 7.1
Hz, 2H), 7.23 (t, J = 7.2 Hz, 2H), 7.19 (t, J = 7.2 Hz, 1H), 5.27 (s,
2H), 2.54 (s, 3H); 13C NMR (125 MHz, CDCl3/CS2) δ 152.77 (C
O), 148.08, 148.00, 146.83, 146.57, 146.39, 146.31, 146.16, 145.98,
145.53, 145.22, 145.17, 144.96, 144.80, 144.64, 144.37, 143.73, 142.96,
142.88, 142.81, 142.66, 142.19, 142.04, 142.00, 141.50, 141.29, 139.48,
138.43, 136.60, 136.58, 136.31, 136.21, 129.61, 129.00, 128.74, 128.47,
128.05, 79.95 (C(sp3) of C60), 79.07 (C(sp3) of C60), 46.78, 21.94;
UV−vis (CHCl3) λmax/nm 257, 319, 419, 453, 682; HRMS (MALDI-
TOF MS) m/z [M + Na]+ calcd for C75H14N2NaO3S 1045.0623,
found 1045.0617.
1
4h (brown solid, mp >300 °C): H NMR (500 MHz, DMSO-d6/
CS2) δ 8.62 (s, 1H), 8.01 (d, J = 8.3 Hz, 2H), 7.42 (d, J = 8.1 Hz, 2H),
6.66 (d, J = 8.4 Hz, 2H), 6.40 (d, J = 8.4 Hz, 2H), 4.10 (t, J = 6.9 Hz,
2H), 3.09 (t, J = 6.9 Hz, 2H), 2.56 (s, 3H); 13C NMR (125 MHz,
DMSO-d6/CS2) δ 156.32, 150.61 (CO), 147.20, 147.07, 146.03,
145.64, 145.57, 145.43, 145.25, 145.21, 144.93, 144.82, 144.33, 144.18,
144.17, 143.93, 143.77, 143.57, 143.30, 143.11, 142.00, 141.90, 141.84,
141.81, 141.35, 141.24, 141.10, 141.00, 140.49, 138.70, 137.25, 136.08,
136.05, 135.21, 129.26, 128.59, 128.27, 126.67, 115.09, 78.97 (C(sp3)
of C60), 77.89 (C(sp3) of C60), 43.57, 32.59, 21.19; UV−vis (CHCl3)
λmax/nm 257, 318, 417, 453, 682; HRMS (MALDI-TOF MS) m/z [M
+ H]+ calcd for C76H17N2O4S 1053.0909, found 1053.0902, [M +
Na]+ calcd for C76H16N2NaO4S 1075.0728, found 1075.0725.
4i (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2) δ
8.11 (d, J = 8.4 Hz, 2H), 7.58−7.61 (m, 2H), 7.45 (tt, J = 7.4, 1.5 Hz,
2H), 7.37−7.42 (m, 3H), 2.52 (s, 3H); 13C NMR (125 MHz, CDCl3/
CS2) δ 151.84 (CO), 148.10, 148.01, 146.77, 146.58, 146.37,
146.34, 146.17, 145.99, 145.59, 145.22, 145.19, 145.15, 144.74, 144.65,
144.38, 144.07, 142.94, 142.83, 142.78, 142.69, 142.09, 142.01, 141.94,
141.55, 141.40, 139.69, 138.41, 136.59, 136.44, 136.20, 134.34, 130.80,
129.66, 129.55, 129.46, 129.16, 81.40 (C(sp3) of C60), 79.00 (C(sp3)
of C60), 21.90.
4c (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.08 (d, J = 8.3 Hz, 2H), 7.39 (d, J = 8.1 Hz, 2H), 4.24 (tt, J = 12.0,
4.0 Hz, 1H), 2.57−2.69 (m, 2H), 2.52 (s, 3H), 1.95−2.03 (m, 2H),
1.85−1.95 (m, 2H), 1.62−1.70 (m, 1H), 1.25−1.36 (m, 3H); 13C
NMR (125 MHz, CDCl3/CS2) δ 151.49 (CO), 148.15, 148.08,
146.75, 146.68, 146.64, 146.43, 146.32, 146.23, 146.09, 145.72, 145.26,
145.21, 145.18, 145.00, 144.96, 144.82, 144.44, 143.90, 143.03, 142.94,
142.92, 142.82, 142.17, 142.07, 142.03, 141.71, 141.41, 139.91, 138.38,
136.87, 136.68, 136.53, 129.59, 128.85, 80.21 (C(sp3) of C60), 78.98
(C(sp3) of C60), 55.93, 29.97, 26.68, 25.22, 21.92; UV−vis (CHCl3)
λmax/nm 256, 317, 417, 453, 682; HRMS (MALDI-TOF MS) m/z [M
+ Na]+ calcd for C74H18N2NaO3S 1037.0936, found 1037.0930.
4d (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.10 (d, J = 8.3 Hz, 2H), 7.40 (d, J = 8.1 Hz, 2H), 4.76 (s, 2H), 4.17
(q, J = 7.1 Hz, 2H), 2.51 (s, 3H), 1.20 (t, J = 7.1 Hz, 3H); 13C NMR
(125 MHz, CDCl3/CS2) δ 167.64 (CO), 152.54 (CO), 148.17,
148.07, 146.73, 146.62, 146.61, 146.42, 146.37, 146.18, 146.11, 145.58,
145.26, 145.25, 145.19, 144.73, 144.65, 144.41, 144.24, 143.27, 142.97,
142.90, 142.86, 142.71, 142.12, 142.07, 141.96, 141.61, 141.36, 139.98,
138.39, 136.77, 136.73, 136.45, 129.61, 128.87, 79.55 (C(sp3) of C60),
79.25 (C(sp3) of C60), 61.90, 43.76, 21.90, 14.11; UV−vis (CHCl3)
λmax/nm 257, 318, 417, 453, 682; HRMS (MALDI-TOF MS) m/z [M
+ Na]+ calcd for C72H14N2NaO5S 1041.0521, found 1041.0517.
4j (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2) δ
8.11 (d, J = 8.4 Hz, 2H), 7.56 (d, J = 8.8 Hz, 2H), 7.42 (d, J = 8.7 Hz,
2H), 7.40 (d, J = 8.4 Hz, 2H), 2.52 (s, 3H).
4k (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.13 (d, J = 8.4 Hz, 2H), 7.50 (d, J = 8.9 Hz, 2H), 7.39 (d, J = 8.4
Hz, 2H), 6.93 (d, J = 9.0 Hz, 2H), 3.78 (s, 3H), 2.52 (s, 3H).
4l (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2) δ
8.14−8.20 (m, 3H), 7.91 (d, J = 8.3 Hz, 1H), 7.87 (d, J = 8.0 Hz, 1H),
7.78 (dd, J = 7.4, 0.8 Hz, 1H), 7.56 (ddd, J = 8.3, 7.1, 1.3 Hz, 1H),
7.47−7.53 (m, 2H), 7.41 (d, J = 8.2 Hz, 2H), 2.54 (s, 3H).
4m (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.13 (d, J = 9.0 Hz, 2H), 7.03 (d, J = 9.0 Hz, 2H), 4.03 (t, J = 7.8 Hz,
2H), 3.92 (s, 3H), 1.93 (quint, J = 7.6 Hz, 2H), 1.45 (sextet, J = 7.5
D
dx.doi.org/10.1021/jo5022772 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
Hz, 2H), 0.96 (t, J = 7.4 Hz, 3H); 13C NMR (125 MHz, CDCl3/CS2)
δ 163.95, 152.27 (CO), 148.11, 148.03, 146.84, 146.60, 146.56,
146.40, 146.29, 146.18, 146.03, 145.60, 145.23, 145.17, 145.14, 145.06,
144.71, 144.40, 143.66, 142.97, 142.90, 142.86, 142.71, 142.15, 142.08,
142.01, 141.66, 141.37, 139.89, 138.41, 136.52, 136.47, 131.20, 131.03,
114.00, 79.96 (C(sp3) of C60), 78.99 (C(sp3) of C60), 55.54, 43.12,
31.71, 20.63, 14.00; UV−vis (CHCl3) λmax/nm 256, 318, 418, 452,
680; HRMS (MALDI-TOF MS) m/z [M + H]+ calcd for
C72H17N2O4S 1005.0909, found 1005.0899, [M + Na]+ calcd for
C72H16N2NaO4S 1027.0728, found 1027.0727.
ASSOCIATED CONTENT
■
S
* Supporting Information
UV−vis spectra of 4b and 6a and 1H and 13C NMR spectra of
the products. This material is available free of charge via the
Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: yht898@yahoo.com.
Notes
■
4n (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 8.44 (s, 4H), 4.04 (t, J = 7.8 Hz, 2H), 1.93 (quint, J = 7.7 Hz, 2H),
1.46 (sextet, J = 7.5 Hz, 2H), 0.96 (t, J = 7.4 Hz, 3H); 13C NMR (125
MHz, CDCl3/CS2) δ 151.86 (CO), 150.78, 148.20, 148.09, 146.67,
146.48, 146.43, 146.28, 146.14, 145.52, 145.32, 145.24, 144.68, 144.62,
144.56, 144.45, 144.24, 143.50, 143.06, 143.00, 142.95, 142.69, 142.21,
142.13, 142.07, 141.62, 141.30, 140.03, 138.57, 136.72, 136.36, 130.26,
124.09, 80.12 (C(sp3) of C60), 79.06 (C(sp3) of C60), 43.33, 31.62,
20.59, 13.95; UV−vis (CHCl3) λmax/nm 257, 318, 418, 453, 680;
HRMS (MALDI-TOF MS) m/z [M + H]+ calcd for C71H14N3O5S
1020.0654, found 1020.0649.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We are grateful for financial support from the National Natural
Science Foundation of China (21202011 and 21272236), the
Natural Science Foundation of Jiangsu Province
(BK20141171), the Priority Academic Program Development
of Jiangsu Higher Education Institutions (PAPD), and the
Jiangsu Key Laboratory of Advanced Catalytic Materials and
Technology (BM2012110).
4o (brown solid, mp >300 °C): 1H NMR (500 MHz, CDCl3/CS2)
δ 4.16 (t, J = 7.8 Hz, 2H), 3.72 (s, 3H), 2.02 (quint, J = 7.7 Hz, 2H),
1.54 (sextet, J = 7.5 Hz, 2H), 1.02 (t, J = 7.4 Hz, 3H); 13C NMR (125
MHz, CDCl3/CS2) δ 153.04 (CO), 148.13, 148.07, 146.65, 146.59,
146.43, 146.37, 146.22, 146.10, 145.59, 145.27, 145.19, 144.84, 144.70,
144.61, 144.40, 143.64, 142.97, 142.93, 142.87, 142.69, 142.17, 142.10,
141.98, 141.67, 141.38, 139.97, 138.45, 136.66, 136.49, 80.23 (C(sp3)
of C60), 78.76 (C(sp3) of C60), 43.25, 43.09, 31.75, 20.64, 14.01; UV−
vis (CHCl3) λmax/nm 256, 318, 417, 453, 680; HRMS (MALDI-TOF
MS) m/z [M + H]+ calcd for C66H13N2O3S 913.0647, found 913.0639,
[M + Na]+ calcd for C66H12N2NaO3S 935.0466, found 935.0463.
NMI-Catalyzed Reaction of Aziridinofullerene 1 with
Benzoyl- and Ester-Substituted Ureas 5a and 5b. A mixture of
aziridinofullerene 1 (for 5a, 17.8 mg, 0.02 mmol; for 5b, 35.6 mg, 0.04
mmol), urea 5a or 5b (2 equiv), and NMI (for 5a, 0.1 mmol, 100 μL
of 1 mol/L NMI solution in chlorobenzene; for 5b, 0.2 mmol, 200 μL
of 1 mol/L NMI solution in chlorobenzene) in 3 mL of dry
chlorobenzene was stirred at 120 °C for the designated time until
completion of the reaction as determined by TLC. The solvent was
removed in vacuo, and the residue was purified on a silica gel column
using CS2/toluene as the eluent to give the product 6a (13.3 mg, 68%)
or 6b (13.9 mg, 36%)
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