Synthesis and oxidation of vinyl derivatives of N-methyl[60]fullereno[c] pyrrolidine

Article abstract of DOI:10.1007/s11172-010-0340-8

Novel organometallic derivatives of N-methyl[60]fullereno[c]pyrrolidine bearing the vinyl fragment at the position 2 of the pyrrolidine ring were synthesized. Their oxidation with 3-chloroperoxybenzoic acid to give N-oxides and epoxides was studied in det

Full text of DOI:10.1007/s11172-010-0340-8

Russian Chemical Bulletin, International Edition, Vol. 59, No. 10, pp. 1964—1966, October, 2010
1964
Synthesis and oxidation of vinyl derivatives of
Nꢀmethyl[60]fullereno[c]pyrrolidine
N. V. Abramova, A. G. Ginzburg, and V. I. Sokolov
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (499) 135 5085. Eꢀmail: stemos@ineos.ac.ru; sokol@ineos.ac.ru
Novel organometallic derivatives of Nꢀmethyl[60]fullereno[c]pyrrolidine bearing the vinyl
fragment at the position 2 of the pyrrolidine ring were synthesized. Their oxidation with
3ꢀchloroperoxybenzoic acid to give Nꢀoxides and epoxides was studied in detail.
Key words: Nꢀmethyl[60]fullereno[c]pyrrolidine, chlorovinylcymantrene, chlorovinylꢀ
ferrocene, cymantrene, cyclopentadienylrhenium tricarbonyl, Nꢀoxides, 3ꢀchloroperoxybenꢀ
zoic acid, Prato reaction.
It is known from the numerous publications on fulꢀ
hydes 2a—e, we synthesized the corresponding fullerenoꢀ
pyrrolidines 3a—e (Scheme 1).
lerenes that [60]fullerene can be modified by 1,3ꢀdipolar
cycloaddition of azomethine ylides (the Prato reaction),
which led to various fullerenopyrrolidines.1,2
Oxidation of organometallic derivatives of fullerenoꢀ
pyrrolidines 3a,b with equimolar amount of 3ꢀchloroperꢀ
oxybenzoic acid (mCPBA) resulted in compounds 4a,b in
Oxidation of fullerenopyrrolidine derivatives at the
nitrogen atom to give fullerenopyrrolidine Nꢀoxides3 could
be regarded as one of the promising methods for further
functionalization of this class of compounds. Studying this
reaction is of interest because the Nꢀoxides are used to
protect an amino group during subsequent transformaꢀ
tions of the molecule. A number of Nꢀoxides bearing orꢀ
ganic substituents at the position 2 of the pyrrolidine ring
were synthesized.3 Organometallic derivatives of fullerenoꢀ
pyrrolidines are of interest due to the effect of the metal
atom on the oxidation. Besides, fullerene derivatives bearꢀ
ing double bond are promising because in their case both
the oxidation of the nitrogen atom and the formation of an
epoxide could occur. In the present work with the aim at
studying this process, from Nꢀmethylglycine 1 and aldeꢀ
1
the yields of 34 and 44%, respectively. In the H NMR
spectra of the synthesized compounds, all signals shifted
downfield by 0.6—1.0 ppm with respect to the starting
fullerenopyrrolidines. This fact is consistent with the pubꢀ
lished data3 suggesting that the oxidation occurred at the
nitrogen atom of the pyrrolidine fragment. The downfield
shift of the signal for the NMe group is the most characꢀ
teristic. Thus, these shifts are 0.5 and 0.8 ppm for comꢀ
pounds 4a and 4b, respectively. No paramagnetism was
observed in the NMR spectra of the compounds syntheꢀ
sized indicating that the metal atom in the organometallic
fragment of the molecule does not oxidized, i.e., the presꢀ
ence of the metal atom does not affect the oxidation of the
fullerenopyrrolidine with mCPBA.
Scheme 1
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1914—1916, October, 2010.
1066ꢀ5285/10/5910ꢀ1964 © 2010 Springer Science+Business Media, Inc.

Oxidation of fullerenopyrrolidines
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 10, October, 2010
1965
Scheme 2
Oxidation of 3c with twofold excess of mCPBA yieldꢀ
ed compound 5 (see Scheme 3). In the 1H NMR spectrum
of 5, the signal for the protons of the Nꢀmethyl group
shifted downfield by 1.3 ppm (with respect to 3c) suggestꢀ
ing formation of the Nꢀoxide. Therefore, no signals for the
double bond were observed, while the multiplets at δ 3.50
and 3.75 were attributed to the protons of the epoxide ring.
These data suggest that the second equivalent of mCPBA
reacts with 3c giving epoxide 5. Thus, oxidation of 3c with
twofold excess of mCPBA involves both the nitrogen atom
and the double bond and does not affect the double bonds
of the fullerene cage; it is of note that the Nꢀoxide is the
first product formed upon oxidation. Like many other
fullerene derivatives, the compounds synthesized are diffiꢀ
cult for an elemental analysis; the content of carbon could
be very low due to insufficient combustion. In this series,
acceptable results of elemental analyses were obtained for
compounds 3d,e.
i. mCPBA (1 eqiuv.), CHCl , 1 h
3
Oxidation of fullerenopyrrolidine 3c was carried out
stepwise (Scheme 3). Since compound 3c contains two reacꢀ
tive centers (the nitrogen atom and the double bond), the
oxidation of 3c could result in both epoxide and Nꢀoxide.
An attempt to prepare compounds 4d,e by oxidation of
chlorovinyl fullerenopyrrolidine derivatives 3d,e failed even
when threefold excess of mCPBA was used (Scheme 4).
Thus, the electronꢀwithdrawing chlorine atom prevents
oxidation of not only the double bond, but also of the
remote tertiary nitrogen atom.
Scheme 3
Scheme 4
i. mCPBA (3 equiv.), CHCl3, 1 h
Experimental
Commercially available [60]fullerene (99.9% pure, G. A.
Razuvaev Institute of Organometallic Chemistry, Russian Acadꢀ
emy of Sciences, Nizhny Novgorod) was used. Formylcycloꢀ
pentadienylrhenium tricarbonyl (2a)4 formylcyclopentadienylꢀ
manganese tricarbohyl (2b)5 were synthesized by the known
methods. 3ꢀFerrocenylacrolein was synthesized from acetylferꢀ
rocene according to the known procedure6, acetylcymantrene
was prepared by published method.7 NꢀMethylꢀ2ꢀ(cycloꢀ
pentadienyl)tricarbonylrhenium[60]fullereno[c]pyrrolidine (3a),
Nꢀmethylꢀ2ꢀ(cyclopentadienyl)tricarbonylmanganese[60]fullerꢀ
eno[c]pyrrolidine (3b), and Nꢀmethylꢀ2ꢀstyryl[60]fullerenoꢀ
[c]pyrrolidine (3c) were synthesized and characterized in our
laboratory earlier.8,9 1H and 13C NMR spectra were recorded on
a Bruker 400 HX spectrometer; chemical shifts were determined
relative to the residual solvent signal and refined to Me4Si. Electroꢀ
spray ionization mass spectrum was recorded on a Agilent 1100
i. mCPBA (1 equiv.), CHCl3, 1 h; ii. mCPBA (2 equiv.), CHCl3, 1 h.
Oxidation of 3c with 1 equivalent of mCPBA afforded
compound 4c. The changes in the chemical shifts in the
1H NMR spectrum, namely, downfield shift of the signal
for the protons of the Nꢀmethyl group by 0.68 ppm (δ 3.36
with respect to δ 2.68 for compound 3c), confirm the
formation of the Nꢀoxide. Other signals also shifted downꢀ
field compared with the signals for the starting compound
by an average of 0.6—1.0 ppm. The 1H NMR spectrum of
4c exhibited signals for the CH=CH group suggesting no
epoxidation.

1966
Russ.Chem.Bull., Int.Ed., Vol. 59, No. 10, October, 2010
Abramova et al.
Series LC/MSD Trap mass spectrometer operating in both the
positive and negative ion modes.
NꢀMethylꢀ2ꢀstyryl[60]fullereno[c]pyrrolidine Nꢀoxide (4c).
To a solution of fullerene 3c (0.02 g, 0.0228 mmol) in CHCl3
(100 mL), a solution of mCPBA (0.0031 g, 0.018 mmol) in CHCl3
(15 mL) was added dropwise over a period of 1 h and stirring was
continued for 30 min. The reaction progress was monitored by
TLC. Purification by column chromatography (SiO2, elution
with CH2Cl2—EtOH, 10 : 1) afforded compound 4c (9 mg, 44%).
1H NMR (CDCl3), δ: 3.36 (s, 3 H, NMe); 5.37 (m, 1 H, CH2);
5.62 (d, 1 H, CH); 5.71 (m, 1 H, CH2); 6.75 (m, 1 H, CH=CH);
7.10 (d, 1 H, CH=CH); 7.39 (m, 3 H, C6H5); 7.60 (m, 2 H,
C6H5).
NꢀMethylꢀ2ꢀepoxystyryl[60]fullereno[c]pyrrolidine Nꢀoxide
(5). To a solution of fullerene 3c (0.04 g, 0.045 mmol) in CHCl3
(150 mL), a solution of mCPBA (0.0062 g, 0.036 mmol) was added
dropwise over a period of 1 h and stirring was continued for 30 min.
The reaction progress was monitored by TLC. Purification by
column chromatography (SiO2, elution with CH2Cl2—EtOH,
10 : 1) afforded compound 5 (16.08 mg, 39%). IR, ν/cm–1: 1085
(NO). 1H NMR (CDCl3), δ: 3.50, 3.75 (m, 2 H, epoxide); 4.10
(s, 3 H, NMe); 5.35, 5.67 (both d, 2 H, CH2); 6.50 (d, 2 H, CH);
8.02 (m, 3 H, Ph); 8.15 (m, 2 H, Ph).
3ꢀChloroꢀ3ꢀcymantrenyl acrolein (2d). To a solution of aceꢀ
tylcymantrene (1 g, 0.004 mol) in anhydrous DMF (6 mL),
a freshly prepared solution of POCl3 (1.25 mL, 2.09 g, 0.013 mol)
in anhydrous DMF (4 mL) was added under argon at 0 °C. The
reaction mixture was stirred at 0 °C for 15 min and 2 h at room
temperature. Then 10% aqueous solution of AcONa (30 mL)
was added and stirring was continued for 1.5 h. The mixture was
extracted with CH2Cl2 (3×50 mL), the organic phases were
washed twice with water, and dried with Na2SO4. The crude
product was purified by column chromatography (SiO2, elution
with hexane—ethyl acetate, 5 : 1) to give 2d (0.75 g, 72%).
1H NMR (CDCl3), δ: 4.95 (br.m, 2 H, Cp); 5.5 (br.m, 2 H, Cp);
6.48 (br.s, 1 H, CCl=CH); 10.14 (br.s, 1 H, CHO).
NꢀMethylꢀ2ꢀ(3ꢀchlorovinylꢀ3ꢀcymantrenyl)[60]fullerenoꢀ
[c]pyrrolidin (3d). A mixture of [60]fullerene (0.1 g, 0.138 mmol),
aldehyde 2d (0.048 g, 0.153 mmol), and Nꢀmethylglycine
(0.0245 g, 0.275 mmol) in toluene (100 mL) was refluxed for 3 h
under argon. The column chromatography (SiO2, elution with
hexane—toluene, 1 : 1) afforded 3d (25.8 mg, 18%). Found (%):
C, 79.87; H, 1.40; N, 1.23. C73H11ClMnNO3. Calculated (%):
The authors are grateful to A. S. Peregudov for the 1H
and 13C NMR spectroscopy and Prof. Cui Xiuling (Zhengꢀ
zhou University, Public´s Republic of China) for the mass
spectrometry.
1
C, 84.28; H, 1.07; N, 1.35. H NMR (CDCl3), δ: 2.89 (s, 3 H,
NMe); 4.19, 4.85 (both d, 1 H, CH2, J = 9.5 Hz); 4.68, 4.80,
5.23, 5.25 (all m, 1 H, Cp); 5.08 (d, 1 H, CH, J = 9.2 Hz); 6.5
(d, 1 H, CH=CCl, J = 8.9 Hz). MS (ESI), m/z: 1042.4 [M+];
896 [M – 3 CO – ClC=CH]+.
NꢀMethylꢀ2ꢀ(3ꢀchlorovinylꢀ3ꢀferrocenyl)[60]fullereno[c]ꢀ
pyrrolidine (3e). A mixture of [60]fullerene (0.1 g, 0.138 mmol),
aldehyde 2e (0.042 g, 0.153 mmol), and Nꢀmethylglycine
(0.0245 g, 0.275 mmol) in toluene (100 mL) was refluxed for 5 h
under argon. Purification by column chromatography (SiO2, eluꢀ
tion with hexane—toluene, 1 : 1) yielded compound 3e (22.6 mg,
16%). Found (%): C, 88.38; H, 1.52; N, 1.23. C75H16ClFeN.
Calculated (%): C, 88.11; H, 1.57; N, 1.37. 1H NMR (CDCl3),
δ: 2.92 (s, 3 H, NMe); 4.05 (s, 5 H, C5H5); 4.21 (d, 1 H, CH2,
J = 9.5 Hz); 4.31, 4.34, 4.55, 4.67 (all m, 1 H, C5H4); 4.90 (d, 1 H,
CH, J = 9.7 Hz); 5.18 (d, 1 H, CH2, J = 9.0 Hz); 6.42 (d, 1 H,
CH=CCl, J = 9.0 Hz). 13C NMR (CDCl3), δ: 40.2 (NMe); 66.7 (C);
68.0 (CH2); 69.6 (CH=CCl); 70.0 (Cp); 140.3—147.3 (C60).
NꢀMethylꢀ2ꢀ(cyclopentadienyl)tricarbonylrhenium[60]ꢀ
fullereno[c]pyrrolidine Nꢀoxide (4a). To a stirred solution of
fullerene 3a (0.02 g, 0.018 mmol) in CHCl3 (100 mL), a solution
of mCPBA (0.0031 g, 0.018 mmol) in CHCl3 (15 mL) was added
dropwise over a period of 1 h and stirring was continued for 30 min.
The reaction progress was monitored by TLC. Purification by
column chromatography (SiO2, elution with CH2Cl2—EtOH,
10 : 1) afforded compound 4a (7 mg, 34%). IR, ν/cm–1: 2040,
1965 (CO); 1075 (NO). 1H NMR (CDCl3) δ: 3.30 (s, 3 H, NMe);
3.40—3.60 (m, 3 H, CH, CH2); 4.10—4.50 (m, 4 H, C5H4).
NꢀMethylꢀ2ꢀ(cyclopentadienyl)tricarbonylmanganese[60]ꢀ
fullereno[c]pyrrolidine Nꢀoxide (4b). To a solution of fullerene
3b (0.02 g, 0.0204 mmol) in CHCl3 (100 mL), a solution of
mCPBA (0.0031 g, 0.018 mmol) in CHCl3 (15 mL) was added
dropwise over a period of 1 h and stirring was continued
for 30 min. The reaction progress was monitored by TLC.
Purification by column chromatography (SiO2, elution with
CH2Cl2—EtOH, 10 : 1) afforded compound 4b (9 mg, 44%). IR,
ν/cm–1: 2020, 1955 (CO); 1070 (NO). 1H NMR (CDCl3), δ:
3.98 (s, 3 H, NMe); 4.26—4.32 (m, 3 H, CH, CH2); 4.34, 4.57,
4.40, 4.42 (all m, 1 H, C5H4).
This work was financially supported by the Russian
Foundation for Basic Research (Project No. 08ꢀ03ꢀ00169).
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Received February 27, 2010;
in revised form July 21, 2010