Reactions of fluoroalkanesulfonyl azides with pyrrole and its derivatives

Article abstract of DOI:10.1016/j.jfluchem.2010.05.005

The reactions of fluoroalkanesulfonyl azides with pyrrole and its derivatives were studied. The reaction proceeded smoothly under mild conditions to give the 3-(fluoroalkanesulfonamido) pyrroles in good yield. The electron donating groups on the pyrrole core accelerated the reaction, while the electron withdrawing groups decelerated it. All the products were fully characterized by spectrum methods, and one of the products was further confirmed by X-ray diffraction analysis. A possible reaction mechanism for these reactions was proposed.

Full text of DOI:10.1016/j.jfluchem.2010.05.005

Journal of Fluorine Chemistry 131 (2010) 867–872
Contents lists available at ScienceDirect
Journal of Fluorine Chemistry
journal homepage: www.elsevier.com/locate/fluor
Reactions of fluoroalkanesulfonyl azides with pyrrole and its derivatives
*
Wanting Xiong, Yong Xin, Jianwei Han, Shizheng Zhu
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, PR China
A R T I C L E I N F O
A B S T R A C T
Article history:
The reactions of fluoroalkanesulfonyl azides with pyrrole and its derivatives were studied. The reaction
proceeded smoothly under mild conditions to give the 3-(fluoroalkanesulfonamido) pyrroles in good
yield. The electron donating groups on the pyrrole core accelerated the reaction, while the electron
withdrawing groups decelerated it. All the products were fully characterized by spectrum methods, and
one of the products was further confirmed by X-ray diffraction analysis. A possible reaction mechanism
for these reactions was proposed.
Received 7 April 2010
Received in revised form 27 April 2010
Accepted 18 May 2010
Available online 25 May 2010
Keywords:
Published by Elsevier B.V.
Fluoroalkanesulfonyl azide
Pyrrole
Dipolar cycloaddition
Fluoroalkanesulfonyl amide
1. Introduction
(10 mL) in a 25 mL three-necked flask. The reaction mixture turned
pale yellow slowly and the nitrogen gas released. After addition,
Many azides, such as phenyl azide, alkane- or arene-sulfonyl
azide and azidoformates, when heated or irradiated, undergo
decomposition and react via a nitrene intermediate [1]. Due to the
1,3-dipolar property of the azide group, they are also readily
reacted with many unsaturated compounds, especially with the
electron-rich olefins via 1,3-dipolar cycloaddition process [2].
However, it was noticed that the reactions of azides with
pyrrole and its derivatives have not been reported up to now.
During our systematical study on the chemical transformation of
fluoroalkanesulfonyl azides 1, we found that numerous aza-
heterocyclic compounds reacted with 1 smoothly. For instance, the
indoles reacted readily with 1 and gave many different products
according to the substituent groups of indoles (Scheme 1) [3].
Considering about the structure similarity between pyrrole and
indole, recently, we investigated the reactions of fluoroalkanesulfo-
nyl azides 1 with pyrrole and its derivatives 2 in detail. All the
reactions proceeded through a [2 + 3] cycloaddition process via a
1,2,3-triazole intermediate. It was also foundthat electronic effect of
the substituent of pyrrole on the reaction process was obvious.
Herein, we report these results and discuss the reaction mechanism.
the reaction temperature was increased to 80 8C, the reaction
mixture turned blue-black. After stirring for 2 h, the reaction was
finished according to TLC analysis. After removing the solvent, the
residue was subjected to flash column chromatography using
petroleum ether–ethyl acetate = 1:1 as eluant, to give the pure
product 3aa as blue oil in a yield of 86%.
Product 3aa was fully characterized by spectroscopic and
elemental analysis. Its 1H NMR spectrum was composed of five
peaks, which are 8.26 (br s), 6.62 (br s), 6.85 (dd), 6.68 (dd) and 6.17
(d) ppm. Two broad singlets could be assigned to two active NHs
(8.26 for SO2NH and 6.62 for pyrrole NH). Comparing with the
standard 1H NMR spectrum of pyrrole (2,5-H at 6.62 ppm, 3,4-H at
6.05 ppm), the two peaks at 6.85 and 6.68 ppm should be 2,5-H of
thepyrrolecore. Theremainedpeakat6.17 ppmwasassignedto4-H
of 3aa. Thus, the RfSO2NH group should be substituted at 3-possition
of the pyrrole ring. A typical broad absorption at 3435 cmÀ1 and
3299 cmÀ1 in its FT-IR spectrum also confirmed the existence of
RfSO2NH group and pyrrole core NH. In addition, the Rf (ICF2C-
F2OCF2CF2) group remained unchanged, because the 19F NMR of 3aa
(À65.5, À82.3, À86.0 and À114.7 ppm) was nearly the same as 1a
(À65.1, À81.7, À86.7 and À113.8). ESI-MS showed that the
molecular weight of 3aa was 488. Together with elemental analysis
and previous literature works, the structure was determined as
3-(3-oxa-5-iodo-octafluoropentanesulfonamido) pyrrole.
2. Results and discussion
The reaction of fluoroalkanesulfonyl azide 1a with pyrrole 2a
was first investigated. At room temperature, 1a (2.2 mmol) was
added dropwise to a solution of pyrrole 2a (2.0 mmol) and MeCN
Under the same reaction conditions, other azides 1(b-d) reacted
with pyrrole 2a smoothly and all gave the 3-(fluoroalkanesulfo-
nylamido) pyrroles in yields of 75–91% (Table 1, Entry 1–4).
Product 3da gave a fine crystal when it was recrystallized in a
solution of petroleum ether and ethyl acetate. Its X-ray diffraction
analysis further confirmed the 3-subsituted structure (Fig. 1) and
* Corresponding author. Tel.: +86 21 54925185; fax: +86 21 64166128.
E-mail address: zhusz@mail.sioc.ac.cn (S. Zhu).
0022-1139/$ – see front matter. Published by Elsevier B.V.
doi:10.1016/j.jfluchem.2010.05.005

[
W. Xiong et al. / Journal of Fluorine Chemistry 131 (2010) 867–872
Scheme 1. Reactions of fluoroalkanesulfonyl azides with indoles.
also showed there were strong intermolecular hydrogen bonds
the product was formed immediately (Table 1, Entry 9–12). It is
clearly that, the electron donating group increased the electron
density of the pyrrole cycle, which accelerated the reaction and
made the reaction process much easier. In contrast to the methyl
substituted pyrroles 2b and 2c, N-phenyl pyrrole 2d reacted with
azides very slowly. After refluxing in CH3CN for 30 h, there was still
more than 10% of 2d remained (Table 1, Entry 13–16). While
˚
between C55O. . .H–N (d OÁ Á ÁH–N 2.047 A) and SO2Á Á ÁH–N (d OÁ Á ÁH–
˚
N 2.471 A) (Fig. 2).
It was noticed that the reaction of N-methyl pyrrole 2b with
azides was finished within 0.5 h (Table 1, Entry 5–9). In the case of
1,2,5-trimethyl pyrrole 2c, when the azide was added dropwise to
the solution of 2c in CH3CN, the nitrogen gas released violently, and
Table 1
Results of reactions of fluoroalkanylsulfonyl azides with indole derivatives
.
Entry
Azide
Pyrrole
Molar ratio of 1:2
Conditions
Time
Product
Yield (%)a
Temperature (8C)
1
2
3
4
1a
1b
1c
1d
]
3aa
3ba
3ca
3da
86
90
91
75
1.1:1
2 h
80
[
3ab
89
5
6
7
8
1a
1b
1c
1d
3bb
3cb
3db
92
90
78
1.1:1
1.1:1
0.5 h
5 min
80
25
]
3ac
81
9
10
11
12
1a
1b
1c
1e
3bc
3cc
3ec
85
88
79

W. Xiong et al. / Journal of Fluorine Chemistry 131 (2010) 867–872
869
Table 1 (Continued )
Entry
Azide
Pyrrole
Molar ratio of 1:2
Conditions
Time
Product
Yield (%)a
Temperature (8C)
13
14
15
16
1a
1b
1c
1e
T
3ad
3bd
3cd
3ed
76(10)b
83(11)b
85(10)b
82(17)b
1.1:1
30 h
32 h
80
17
1c
1c
[1,0]1.1:1
80
80
–
–
–
–
18
2 d
a
Isolated yield based on 2.
Recover of 2.
b
[(Fig._1)TD$FIG]
dipolar cycloaddition process. To the best of our knowledge, the
former proceeded at high temperature (usually above 110 8C for
fluoroalkanesulfonyl azides 1) and the latter occurred at lower
temperature [4]. Thus, the reaction pathway for these reactions is
proposed as shown in Scheme 2.
In this reaction, the emission of gas was observed from rt to
80 8C. So the probable pathway is a dipolar cycloaddition
followed by a ring-opening process. The [2 + 3] cycloaddition
Fig. 1. Molecular structure of 3da.
process gave two 1,2,3-triazole intermediates
A and B.
Considering about the charge distribution of azide 1 and pyrrole
2, triazole A should be the major intermediate. Due to the strong
electron withdrawing property of RfSO2NH group, they are
unstable and ready to release nitrogen gas to form aziridine
intermediate D, with subsequent ring-opening and H-shift
process gave the final product 3 [5]. On the other hand,
when the N–N bond breaking of the triazole intermediate A
2-acetyl pyrrole and N-t-butoxycarbonyl pyrrole both have an
electron withdrawing group on the pyrrole cycle, they did not react
with the azide even refluxing in CH3CN for 32 h or even 2d (Table 1,
Entry 17, 18).
Generally speaking, there are two types of mechanism for the
r[(Fig._2)TD$FIG] eactions of azide compounds, which are nitrene intermediate and
Fig. 2. Packing map of compound 3da.
[(Scheme_2)TD$FIG]
Scheme 2. Probable mechanism of the reaction of fluoroalkanesulfonyl azides with pyrrole.

870
W. Xiong et al. / Journal of Fluorine Chemistry 131 (2010) 867–872
occurred, the zwitterion intermediate C was formed, which
was also ready to lose N2 and finally form the product 3. But
5.2. 3-(3-Oxa-octafluoropentanesulfonamido) pyrrole 3ba
the similar zwitterion intermediate
E
did not afford the
Blue oil. IR (KBr) cmÀ1: 3438, 3299, 1560, 1419, 1330, 1284,
1144. 1H NMR (CDCl3, 300 MHz):
d = 8.25 (1H, br s, NH), 6.84 (1H,
unfavored amidine product G. Thus, compound 3 were obtained
exclusively [6].
d, J = 2.4 Hz), 6.68 (1H, quart, J = 3.0 Hz), 6.56 (1H, br s, NH), 6.16
(1H, d, J = 1.5 Hz), 5.80 (1H, tt, J = 3.0, 51.2 Hz, HCF2). 19F NMR
(CDCl3, 282 MHz):
d
= À81.4 (2F, t, J = 12.4 Hz, CF2O), À88.4 (2F, m,
3. Conclusion
OCF2), À114.2 (2F, s, CF2S), À137.3 (2F, td, J = 4.2, 52.5 Hz, CF2H).
MS (EI) m/z: 362 (M+, 8), 81 (M-RfSO2, 100). HRMS (EI) m/z calcd.
for C8H6F8N2O3S: 361.9971; Found: 361.9982. Anal. Calcd for
C8H6F8N2O3S: C, 26.53; H, 1.67; N, 7.73%. Found: C, 26.74; H, 1.75;
N, 7.99%.
We conducted a detailed investigation on the reactions of
fluoroalkanesulfonyl azides with pyrrole and its derivatives and
found that the reaction could proceed smoothly under mild
conditions and in good yield to give the 3-(fluoroalkanesulfony-
lamido) pyrroles as the exclusive products. It was found that
electron donating groups on the pyrrole core accelerated the
reaction, while the electron withdrawing groups decelerated it.
The structure of the product was further confirmed by X-ray
diffraction analysis. The probable mechanism was proposed as a
[2 + 3] dipolar cycloaddition process followed by ring-opening
process.
5.3. 3-(Perfluorobutanesulfonamido) pyrrole 3ca
Blue solid. Mp = 107–109 8C. IR (KBr) cmÀ1: 3410, 3265, 1556,
1417, 1364, 1237, 1185, 1141. 1H NMR (acetone-d6, 300 MHz):
d
= 6.90 (1H, d, J = 1.8 Hz), 6.75 (1H, d, J = 1.8 Hz), 6.11 (1H, s). 19F
NMR (acetone-d6, 282 MHz):
d
= À82.1 (3F, t, J = 9.6 Hz, CF3),
À112.4 (2F, t, J = 14.2 Hz, CF2S), À122.3 (2F, s, CF2), À127.1 (2F, dt,
J = 7.1, 13.8 Hz, CF2). MS (ESI) m/z: 365.1 ([M + H]+). HRMS (ESI) m/z
364.9991 ([M + H]+, C8H6F9N2O2S required 365.0001). Anal. Calcd
for C8H5F9N2O2S: C, 26.38; H, 1.38; N, 7.69%. Found: C, 26.67; H,
1.19; N, 7.82%.
4. Experimental
Melting points are measured on a Temp-Melt apparatus and are
uncorrected. 1H (300 MHz), 13C NMR (75 MHz) and 19F NMR
(282 MHz) spectra were recorded on a Bruker AM-300 ultra shield,
300 MHz, high performance digital FT-NMR spectrometer with
Me4Si and CFCl3 as the internal and external standards, respec-
5.4. 3-(Isopropoxycarbonyldifluoromethenesulfonamido) pyrrole 3da
Blue solid. Mp = 89–91 8C. IR (KBr) cmÀ1: 3421, 3297, 1757,
1560, 1429, 1398, 1173, 1093. 1H NMR (CDCl3, 300 MHz):
d = 8.21
tively. FT-IR spectra were obtained with
a Nicolet AV-360
(1H, br s, NH), 6.87 (1H, s), 6.68 (1H, quart, J = 2.7 Hz), 6.44 (1H, br s,
NH), 6.20 (1H, s), 5.22 (1H, quart, J = 6.0 Hz, OCH), 1.36 (6H, d,
spectrophotometer. Low resolution mass spectra (LRMS) and high
resolution mass spectra (HRMS) were obtained on a Finnigan GC–
MS 4021 and a Finnigan MAT-8430 instrument using the electron
impact ionization technique (70 eV) or Electrospray Ionization.
Elemental analyses were performed by this Institute. Single crystal
X-ray structure analysis was performed on a Bruker P4 instrument.
All solvents and reagents were used without further purification
unless otherwise stated.
J = 6.0 Hz, 2CH3). 19F NMR (CDCl3, 282 MHz):
d
= À106.8 (s, CF2S).
MS (ESI) m/z: 283.1 ([M + H]+). HRMS (EI) m/z calcd. for
C9H12F2N2O4S: 282.0486; Found: 282.0484.
Crystal data for C9H12F2N2O4S: MW = 282.27, triclinic, space
˚
group PÀ1, a = 7.1451 (6), b = 8.6746(7), c = 11.0128(10) A,
3
˚
a
= 70.000(8), ( = 71.190(8),
g
= 87.162(7), V = 605.74(9) A , Z = 2,
Dc = 1.548 mg/m3,
F
(0 0 0) = 292,
crystal
dimension
˚
0.26 mm  0.22 mm  0.17 mm, radiation, Mo Ka (
l
= 0.711 A),
5.30 ꢀ 2( ꢀ 50.48, intensity data were collected at 293 K with a
Bruker axs D8 diffractometer, and employing (/2( scanning
technique, in the range of À8 ꢀ h ꢀ 8, À10 ꢀ k ꢀ 10,
À13 ꢀ l ꢀ 13; The structure was solved by a direct method, all
non-hydrogen atoms were positioned and anisotropic thermal
5. General procedure
To a solution of pyrrole 2a (0.14 mL, 2.0 mmol) and MeCN
10 mL in a 25 mL three-necked flask, 1a (998 mg, 2.2 mmol) was
added dropwise at room temperature. After addition, the mixture
was heated to 80 8C for 2 h. TLC analysis showed the reaction was
finished. Then the solvent was removed using rotary evaporator
under vacuum. The product 3aa (839 mg, 86%) was obtained by
flash column chromatography (using petroleum ether–ethyl
acetate = 1:1 as eluant).
parameters refined from 2158 observed reflections with
(int) = 0.0344 by a full-matrix least-squares technique converged
to R = 0.0629 and Rw = 0.0757.
R
CCDC reference number is 771792.
5.5. N-Methyl-3-(3-oxa-5-iodo-octafluoropentanesulfonamido)
5.1. 3-(3-Oxa-5-iodo-octafluoropentanesulfonamido) pyrrole 3aa
pyrrole 3ab
Blue oil. IR (KBr) cmÀ1: 3435, 3299, 2962, 1591, 1419, 1336,
Orange oil. IR (KBr) cmÀ1: 3297, 2953, 1515, 1421, 1336, 1294,
1295, 1141. 1H NMR (CDCl3, 300 MHz):
d
= 8.26 (1H, br s, NH), 6.85
(1H, quart, J = 2.4 Hz), 6.68 (1H, quart, J = 2.7 Hz), 6.62 (1H, br s,
NH), 6.17 (1H, d, J = 1.8 Hz). 13C NMR (CDCl3, 75 MHz):
= 128.2,
1092. 1H NMR (CDCl3, 300 MHz):
d
= 6.62 (1H, s), 6.41 (1H, t,
J = 2.4 Hz), 6.38 (1H, br s, NH), 6.00 (1H, s), 3.55 (3H, s, NCH3). 19
NMR (CDCl3, 282 MHz):
F
d
d
= À65.3 (2F, t, J = 5.6 Hz, ICF2), À82.2 (2F, t,
115.8 (tt, J = 286.8 Hz, 44 Hz), 114.8 (tt, J = 286.8 Hz, 44 Hz), 113.0
(tt, J = 286.8 Hz, 44 Hz), 117.6, 116.7, 115.4, 106.8, 87.8 (tt,
J = 317.8 Hz, 44 Hz). (Due to the complicated couplings, the
chemical shifts of Rf are not supplied, similarly hereinafter.) 19F
J = 13.3 Hz, CF2O), À85.9 (2F, m, OCF2), À114.6 (2F, s, CF2S). MS (ESI)
m/z: 502.8 ([M + H]+), 524.8 ([M + Na]+). Anal. Calcd for C9H7F8I-
N2O3S: C, 21.53; H, 1.41; N, 5.58%. Found: C, 21.90; H, 1.74; N, 5.61%.
NMR (CDCl3, 282 MHz):
d
= À65.5 (2F, t, J = 6.5 Hz, ICF2), À82.3
5.6. N-Methyl-3-(3-oxa-octafluoropentanesulfonamido) pyrrole 3bb
(2F, t, J = 12.7 Hz, CF2O), À86.0 (2F, m, OCF2), À114.7 (2F, s, CF2S).
MS (ESI) m/z: 489.0 ([M + H]+). HRMS (EI) m/z calcd. for
C8H5F8IN2O3S: 487.8938; Found: 487.8929. Anal. Calcd for
C8H5F8IN2O3S: C, 19.69; H, 1.03; N, 5.74%. Found: C, 19.98; H,
0.92; N, 5.49%.
Yellow oil. IR (KBr) cmÀ1: 3299, 2962, 1516, 1421, 1329, 1285,
1136, 1010. 1H NMR (CDCl3, 300 MHz):
d
= 6.61 (1H, s), 6.41 (1H, s),
6.38 (1H, br s, NH), 5.99 (1H, s), 5.73 (1H, tt, J = 3.0, 52.8 Hz, HCF2),
3.55 (3H, s, NCH3). 19F NMR (CDCl3, 282 MHz):
= À81.9 (2F, t,
d

W. Xiong et al. / Journal of Fluorine Chemistry 131 (2010) 867–872
871
J = 10.7 Hz, CF2O), À88.9 (2F, m, OCF2), À114.7 (2F, s, CF2S), À137.8
(2F, td, J = 5.6, 53.6 Hz, CF2H). MS (ESI) m/z: 377.0 ([M + H]+), 399.0
([M + Na]+).Anal. Calcd for C9H8F8N2O3S: C, 28.73; H, 2.14; N,
7.45%. Found: C, 29.04; H, 2.46; N, 7.43%.
2.17 (3H, s, CH3), 2.14 (3H, s, CH3). 19F NMR (CDCl3, 282 MHz):
d
= À107.0 (2F, s, CF2S). MS (ESI) m/z: 297.0 ([M + H]+), 319.0
([M + Na]+). Anal. Calcd for C10H14F2N2O4S: C, 40.54; H, 4.76; N,
9.45%. Found: C, 40.41; H, 4.78; N, 9.11%.
5.7. N-Methyl-3-(perfluorobutanesulfonamido) pyrrole 3cb
5.13. N-Phenyl-3-(3-oxa-5-iodo-octafluoropentanesulfonamido)
pyrrole 3ad
White solid. Mp = 42–44 8C. IR (KBr) cmÀ1: 3301, 2955, 1516,
1422, 1352, 1189, 1141, 1035. 1H NMR (CDCl3, 300 MHz):
d
= 6.63
(1H, s), 6.42 (1H, t, J = 2.7 Hz), 6.40 (1H, br s, NH), 6.00 (1H, s), 3.56
(3H, s, NCH3). 19F NMR (CDCl3, 282 MHz):
Red solid. Mp = 74–76 8C. IR (KBr) cmÀ1: 3275, 1600, 1519, 1451,
1399, 1330, 1291, 1121. 1H NMR (CDCl3, 300 MHz):
d = 7.41–7.36
d
= À81.3 (3F, t,
(2H, m), 7.30 À 7.21 (3H, m), 7.08 (1H, s), 6.90 (1H, t, J = 2.7 Hz), 6.41
J = 10.2 Hz, CF3), À111.0 (2F, t, J = 13.5 Hz, CF2S), À121.5 (2F, m,
CF2), 126.4 (2F dt, J = 6.2, 13.0 Hz, CF2). MS (ESI) m/z: 379.0
([M + H]+), 401.0 ([M + Na]+) Anal. Calcd for C9H7F9N2O2S: C, 28.58;
H, 1.87; N, 7.41%. Found: C, 28.95; H, 2.18; N, 7.26%.
(1H, br s, NH), 6.22 (1H, t, J = 2.7 Hz). 19F NMR (CDCl3, 282 MHz):
d
= À65.4 (2F, t, J = 5.9 Hz, ICF2), À82.1 (2F, t, J = 12.7 Hz, CF2O),
À86.0 (2F, m, OCF2), À114.5 (2F, s, CF2S). MS (ESI) m/z: 565.0
([M + H]+), 587.0 ([M + Na]+). Anal. Calcd for C14H9F8IN2O3S: C,
29.80; H, 1.61; N, 4.97%. Found: C, 29.94; H, 1.88; N, 5.04%.
5.8. N-Methyl-3-(isopropoxycarbonyldifluoromethenesulfonamido)
pyrrole 3db
5.14. N-Phenyl-3-(3-oxa-octafluoropentanesulfonamido) pyrrole
3bd
Orange solid. Mp = 55–57 8C. IR (KBr) cmÀ1: 3296, 2988, 2942,
1766, 1515, 1379, 1304, 1189, 1097. 1H NMR (CDCl3, 300 MHz):
Red oil. IR (KBr) cmÀ1: 3307, 1703, 1601, 1513, 1426, 1109,
d
= 6.69 (1H, s), 6.47 (1H, s), 6.34 (1H, br s, NH), 6.08 (1H, s), 5.22
(1H, quint, J = 6.3 Hz, OCH), 3.60 (3H, s, NCH3), 1.35 (6H, d,
J = 6.0 Hz, 2CH3). 19F NMR (CDCl3, 282 MHz):
1008. 1H NMR (CDCl3, 300 MHz):
d = 7.46–7.41 (2H, m), 7.35–7.25
(3H, m), 7.13 (1H, s), 6.95 (1H, t, J = 3.0 Hz), 6.57 (1H, br s, NH), 6.27
(1H, t, J = 3.0 Hz), 5.83 (1H, tt, J = 3.0, 52.5 Hz, HCF2). 19F NMR
d
= À106.7 (2F, s,
CF2S). MS (ESI) m/z: 297.1 ([M + H]+), 319.0 ([M + Na]+). Anal. Calcd
for C10H14F2N2O4S: C, 40.54; H, 4.76; N, 9.45%. Found: C, 40.61; H,
4.72; N, 9.22%.
(CDCl3, 282 MHz):
d
= À81.9 (2F, t, J = 12.0 Hz, CF2O), À88.8 (2F, m,
OCF2), À114.6 (2F, s, CF2S), À137.7 (2F, td, J = 4.9, 50.8 Hz, CF2H).
MS (ESI) m/z: 439.0 ([M + H]+). Anal. Calcd for C14H10F8N2O3S: C,
38.36; H, 2.30; N, 6.39%. Found: C, 38.60; H, 2.38; N, 6.50%.
5.9. 1,2,5-Trimethyl-3-(3-oxa-5-iodo-
octafluoropentanesulfonamido) pyrrole 3ac
5.15. N-Phenyl-3-(perfluorobutanesulfonamido) pyrrole 3cd
Red solid. Mp = 95–97 8C. IR (KBr) cmÀ1: 3269, 1512, 1413, 1332,
Red solid. Mp = 59–61 8C. IR (KBr) cmÀ1: 3304, 2927, 1705,
1292, 1175, 1151, 1092. 1HNMR(CDCl3, 300 MHz):
d
= 6.18(1H, brs,
NH), 5.78 (1H, s), 3.35 (3H, s, NCH3), 2.17 (3H, s, CH3), 2.15 (3H, s,
CH3). 19F NMR (CDCl3, 282 MHz):
1601, 1513, 1402, 1351, 1240, 1140, 1034. 1H NMR (CDCl3,
300 MHz):
6.90 (1H, t, J = 2.4 Hz), 6.47 (1H, br s, NH), 6.22 (1H, t, J = 2.4 Hz). 19
NMR (CDCl3, 282 MHz):
d = 7.41–7.36 (2H, m), 7.31–7.21 (3H, m), 7.09 (1H, s),
d
= À65.3 (2F, t, J = 5.6 Hz, ICF2),
F
À82.1 (2F, t, J = 13.3 Hz, CF2O), À86.0 (2F, m, OCF2), À115.1 (2F, s,
CF2S). MS(ESI)m/z:531.0([M + H]+).Anal. CalcdforC11H11F8IN2O3S:
C, 24.92; H, 2.09; N, 5.28%. Found: C, 25.18; H, 2.42; N, 5.44%.
d
= À81.1(3F, t, J = 9.3 Hz, CF3), À110.9 (2F,
t, J = 13.0 Hz, CF2S), À121.4 (2F, s, CF2), À126.4 (2F, dt, J = 4.8,
13.9 Hz, CF2). MS (ESI) m/z: 441.0 ([M + H]+), 463.0 ([M + Na]+).
Anal. Calcd for C14H9F9N2O2S: C, 38.19; H, 2.06; N, 6.36%. Found: C,
38.51; H, 2.40; N, 6.36%.
5.10. 1,2,5-Trimethyl-3-(3-oxa-octafluoropentanesulfonamido)
pyrrole 3bc
5.16. N-Phenyl-3-(methoxycarbonyldifluoromethenesulfonamido)
Red oil. IR (KBr) cmÀ1: 3226, 2928, 1614, 1525, 1412, 1333,
pyrrole 3ed
1219. 1H NMR (CDCl3, 300 MHz):
d
= 6.25 (1H, br s, NH), 5.82 (1H,
tt, J = 3.0, 51.2 Hz, HCF2), 5.77 (1H, s), 3.35 (3H, s, NCH3), 2.16 (3H, s,
CH3), 2.14 (3H, s, CH3). 19F NMR (CDCl3, 282 MHz):
Red solid. Mp = 78–80 8C. IR (KBr) cmÀ1: 3286, 1766, 1598,
d
= À81.8 (2F, t,
1509, 1440, 1318, 1134. 1H NMR (CDCl3, 300 MHz):
d = 7.46–7.40
J = 13.4 Hz, CF2O), À89.0 (2F, m, OCF2), À115.3 (2F, s, CF2S), À137.8
(2F, td, J = 5.1, 51.0 Hz, CF2H). MS (ESI) m/z: 405.0 ([M + H]+). Anal.
Calcd for C11H12F8N2O3S: C, 32.68; H, 2.99; N, 6.93%. Found: C,
32.70; H, 3.02; N, 7.20%.
(2H, m), 7.35 À 7.28 (3H, m), 7.15 (1H, s), 6.95 (1H, quart,
J = 2.7 Hz), 6.40 (1H, br s, NH), 6.29 (1H, t, J = 2.7 Hz), 3.96 (3H, s,
OCH3). 19F NMR (CDCl3, 282 MHz):
d
= À106.5 (2F, s, CF2S). MS (ESI)
m/z: 331.0([M + H]+), 353.0 ([M + Na]+). Anal. Calcd for
13H12F2N2O4S: C, 47.27; H, 3.66; N, 8.48%. Found: C, 47.28; H,
C
5.11. 1,2,5-Trimethyl-3-(perfluorobutanesulfonamido) pyrrole 3cc
Red solid. Mp = 53–55 8C. IR (KBr) cmÀ1: 3251, 1520, 1335, 1136,
3.80; N, 8.41%.
Acknowledgements
1030, 1009. 1H NMR (CDCl3, 300 MHz):
d
= 6.25 (1H, br s, NH), 5.77
(1H, s), 3.35 (3H, s, NCH3), 2.17 (3H, s, ArCH3), 2.15 (3H, s, ArCH3). 19
NMR(CDCl3,282 MHz):
F
This work is financially supported by the National Natural
Science Foundation of China (NNSFC) (No. 20972178). We express
our gratitude to Professor Yuepeng Cai from South China Normal
Universityforhis helponthesinglecrystalX-raydiffractionanalysis.
d
= À81.1(3F,t,J = 9.6 Hz,CF3),À115.5(2F,t,
J = 13.3 Hz, CF2S), À121.4 (2F, m, CF2), À126.4 (2F, tt, J = 5.6, 14.4 Hz,
CF2).MS(ESI)m/z:407.0([M + H]+).Anal.CalcdforC11H11F9N2O2S:C,
32.52; H, 2.73; N, 6.90%. Found: C, 32.49; H, 2.98; N, 7.11%.
References
5.12. 1,2,5-Trimethyl-3-
[1] (a) W. Lwowski, T.W. Mattingly, Tetrahedron Lett. 3 (1962) 277–280;
(b) M.F. Sloan, T.J. Prosser, N.R. Newburg, D.S. Breslow, Tetrahedron Lett. 6 (1964)
2945–2949;
(methoxycarbonyldifluoromethenesulfonamido) pyrrole 3ec
Red solid, Mp = 91–93 8C. 1H NMR (CDCl3, 300 MHz):
(1H, br s, NH), 5.81 (1H, br s), 3.97 (3H, s, OCH3), 3.35 (3H, s, NCH3),
d = 6.12
(c) W. Lwowski, T.J. Maricich, J. Am. Chem. Soc. 87 (1965) 3630–3637;
(d) R.A. Abramovitch, G.N. Knaus, V. Uma, J. Am. Chem. Soc. 91 (1969) 7532–7533;

872
W. Xiong et al. / Journal of Fluorine Chemistry 131 (2010) 867–872
(e) R. Poe, J. Grayzar, M.J.T. Young, E. Leyva, K.A. Schnapp, M.S. Platz, J. Am. Chem.
[4] S.Z. Zhu, P. He, J.W. Zhao, X. Cai, J. Fluorine Chem. 125 (2004) 445–450.
Soc. 113 (1991) 3209–3211;
[5] (a) A. Padwa, 1,3-Dipolarcycloaddition Chemistry, Wiley, New York, 1985(Chapter
(f) S.Z. Zhu, J. Chem. Soc., Perkin Trans. I 12 (1994) 2077–2081.
5);
[2] (a) R. Huisgen, L. Mobius, G. Szeimies, Chem. Ber. 98 (1965) 1138–1152;
(b) W.M. Peng, S.Z. Zhu, J. Fluorine Chem. 116 (2002) 81–86.
[3] (a) S.Z. Zhu, Y. Xu, Tetrahedron 55 (1999) 13725–13734;
(b) S.Z. Zhu, P. He, J. Fluorine Chem. 125 (2004) 1529–1536;
(c) S.Z. Zhu, P. He, J. Fluorine Chem. 126 (2005) 113–120.
(b) J. Bourgois, A. Mathieu, F. Texier, J. Heterocycl. Chem. 21 (1984) 513–
515.
[6] R. Fusco, G. Bianchetti, S. Rossi, Gazz. Chim. Ital. 91 (1961) 933–957.