Copper-catalyzed tandem synthesis of tetrasubstituted pyrimidines from alkynes, sulfonyl azides, trichloroacetonitrile, and tetramethylguanidine

Article abstract of DOI:10.1055/s-0032-1317951

The synthesis of a novel class of pyrimidine derivatives via a copper-catalyzed tandem reaction of trichloroacetonitrile, 1,1,3,3- tetramethylguanidine, sulfonyl azides, and terminal alkynes is described. Georg Thieme Verlag Stuttgart New York.

Full text of DOI:10.1055/s-0032-1317951

LETTER
▌165
lCettoerpper-Catalyzed Tandem Synthesis of Tetrasubstituted Pyrimidines from
Alkynes, Sulfonyl Azides, Trichloroacetonitrile, and Tetramethylguanidine
Synthesis of Tetrasubstituted Pyrimidines
Issa Yavari,* Manijeh Nematpour
Department of Chemistry, Tarbiat Modares University, PO Box 14115-175, Tehran, Iran
Fax +98(21)82883455; E-mail: yavarisa@modares.ac.ir
Received: 27.10.2012; Accepted after revision: 05.12.2012
eral catalysts such as CuI, CuBr, CuCl, and copper pow-
Abstract: The synthesis of a novel class of pyrimidine derivatives
der were tested with CuI giving the best results. Among
via a copper-catalyzed tandem reaction of trichloroacetonitrile,
several solvents screened, MeCN was the best. When the
1,1,3,3-tetramethylguanidine, sulfonyl azides, and terminal alkynes
reaction was performed in MeCN in the presence of one
equivalent of Et3N at room temperature for eight hours, it
was found that the desired product 5a was indeed obtained
in 83% yield (Table 1). Thus, the optimized reaction con-
ditions used were 10 mol% of CuI, 1 mmol of alkyne, 1.2
mmol of sulfonyl azide, 1 mmol of 3, and 1 mmol of 4 in
MeCN at room temperature.
is described.
Keywords: pyrimidine, ketenimines, tandem reaction, sulfonyl
azide, terminal alkyne, trichloroacetonitrile, 1,1,3,3-tetramethyl-
guanidine
In recent years, intensive studies in medicinal chemistry
with regard to the structure–activity relationships of com-
pounds being used in clinical praxis have revealed the ex-
ceptional position of heterocycles. Moreover, a large
number of bioactive natural products contain a heteroat-
om. Therefore, the development of reliable and efficient
methods for constructing heterocyclic frameworks is of
major importance. Pyrimidine derivatives exhibit impor-
tant biological activities and are widely used as key build-
ing blocks for pharmaceutical agents.1–3 The pyrimidine
skeleton has also been found in several marine natural
products with interesting bioactivities.4 Consequently,
several methods have been developed for construction of
this heterocyclic system.5–7 This biological and synthetic
significance places this scaffold in a prestigious position
in medicinal chemistry research.
Ketenimines8 have attracted much attention due to their
diverse chemical reactivity.9–12 One of the attractive meth-
ods for the generation of ketenimines is the copper-cata-
lyzed azide–alkyne cycloaddition (Table 1).13,14 The
formation of ketenimine intermediates from terminal
alkynes and sulfonyl azides, in the presence of Et3N
and copper catalysts,15 has encouraged us to trap these
intermediates using various nucleophilic addition reac-
tions.16–18
Phenylacetylene readily participates in the coupling reac-
tion to furnish the corresponding N-[6-(dimethylamino)-
5-phenyl-2-(trichloromethyl)pyrimidin-4-yl]-4-aryl(al-
kyl)sulfonamides 5a–c in good yields (Table 1). Aliphatic
acetylenes served as low-yielding substrates compared to
phenylacetylene. Aromatic and aliphatic sulfonyl azides
reacted efficiently, and the corresponding products were
obtained in good yields.
1
Structures of compounds 5a–i were assigned by IR, H
1
NMR, 13C NMR, and mass spectral data. The H NMR
spectrum of 5a exhibited three singlets for methyl (δ =
2.87 ppm), dimethyl amino (δ = 2.95 ppm), and NH (δ =
8.03 ppm) protons, along with characteristic multiplets for
the phenyl protons. The 13C NMR spectrum of 5a exhibits
15 signals in agreement with the proposed structure. The
mass spectrum of 5a displayed the molecular ion peak at
m/z = 484. The NMR spectra of compounds 5b–i are sim-
ilar to those of 5a, except for the substituents, which
showed characteristic signals in the appropriate regions of
the spectra.
A plausible mechanism for the formation of compounds 5
is given in Scheme 1. The yellow copper acetylide 7,
formed from 1 and CuI, undergoes a 1,3-dipolar cycload-
dition reaction with sulfonyl azide 2, to generate the tri-
azole derivative 8.20 This intermediate can then react by
ring opening leading to the formation of α-diazoimino
species 9 and thereafter ketenimine 10 by loss of nitrogen
gas.21,22 Intermediate 6, formed from 3 and 4, undergoes a
nucleophilic addition reaction with ketenimine 10 to af-
ford 11. This intermediate is converted into 5 by ring-
formation reaction, loss of dimethylamine, and tautomer-
ization.
Herein, we report a simple and efficient procedure for the
synthesis of N-[6-(dimethylamino)-5-aryl(alkyl)-2-(tri-
chloromethyl)pyrimidin-4-yl]-4-aryl(alkyl)sulfonamide
via the copper-catalyzed four-component coupling reac-
tion of terminal alkynes 1, sulfonyl azides 2, trichloro-
acetonitrile (3), and 1,1,3,3-tetramethylguanidine (4,
Table 1).19
Initially, phenylacetylene (1a), p-toluenesulfonyl azide
(2a), 3, and 4 were selected as the model substrates. Sev-
In conclusion, we have developed a multicomponent reac-
tion involving ketenimine intermediates, 1,1,3,3-tetra-
methylguanidine, and trichloroacetonitrile, which
provides a new route to the synthesis of functionalized
pyrimidine derivatives in moderate to good yields.
SYNLETT 2013, 24, 0165–0168
Advanced online publication: 04.01.2013
DOI: 10.1055/s-0032-1317951; Art ID: ST-2012-D0909-L
© Georg Thieme Verlag Stuttgart · New York
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6

166
I. Yavari, M. Nematpour
LETTER
Table 1 Copper-Catalyzed Azide–Alkyne Cycloaddition for the Synthesis of 5
NH
+
CCl3CN
Me2N
NMe2
3
4
MeCN, r.t.
O
O
NH NMe2
S
N
HN
R2
O
O
R1
R1
Cl3C
N
NMe2
CuI (10 mol%)
Et3N, MeCN
S
N
R2
1
+
C
O
O
r.t., 8 h
Me2N
N
CCl3
S
R1
5
R2
N3
2
Entry
1, 2, 5
R1
R2
Yield of 5 (%)
1
2
3
4
5
6
7
8
9
a
b
c
d
e
f
Ph
4-Tol
Ph
83
87
79
65
63
60
60
57
52
Ph
Ph
Me
n-Pr
n-Pr
n-Pr
n-Bu
n-Bu
n-Bu
4-Tol
Ph
Me
g
h
i
4-Tol
Ph
Me
SO2R2
R1
N
Cu
N2
R1
N
H+
2
R1
Cu
CuI
1 +
N
SO2R2
– N2
Cu
N
7
8
9
3 + 4
NH NMe2
SO2R2
SO2R2
SO2R2
N
N
N
C
Cl3C
N
NMe2
R1
R1
– NHMe2
tautomerization
cyclization
CCl3
NH
NH
–
6
5
Me2N
+
Me2N
R1
Me2N
Me2N
N
CCl3
N
10
11
12
Scheme 1
(5) Rewcastle, G. W. Comprehensive Heterocyclic Chemistry
III: Pyrimidines and their Benzo Derivatives; Vol. 8;
Elsevier: Oxford, 2008, 117–272.
(6) von Angerer, S. Six-Membered Hetarenes with Two
Identical Heteroatoms: Pyrimidines, In Science of Synthesis;
Vol. 16; Thieme: Stuttgart, 2003, 379–572.
(7) Brown, D. J.; Evans, R. F.; Cowden, W. B.; Fenn, M. D. The
Pyrimidines, In Chemistry of Heterocyclic Compounds; Vol.
52; Taylor, E. C., Ed.; Wiley: New York, 1994, 1.
(8) Bae, I.; Han, H.; Chang, S. J. Am. Chem. Soc. 2005, 127,
2038.
References and Notes
(1) Sasada, T.; Kobayashi, F.; Sakai, N.; Konakahara, T. Org.
Lett. 2009, 11, 2161.
(2) Ahmad, O. K.; Hill, M. D.; Movassaghi, M. J. Org. Chem.
2009, 74, 8460.
(3) Barthakur, M. G.; Borthakur, M.; Devi, P.; Saikia, C. J.;
Saikia, A.; Bora, U.; Chetia, A.; Boruah, R. C. Synlett 2007,
223.
(4) Heys, L.; Moore, C. G.; Murphy, P. J. Chem. Soc. Rev. 2000,
29, 57.
(9) Staudinger, H.; Hauser, E. Helv. Chim. Acta 1921, 4, 887.
Synlett 2013, 24, 165–168
© Georg Thieme Verlag Stuttgart · New York

LETTER
Synthesis of Tetrasubstituted Pyrimidines
167
(10) Lu, P.; Wang, Y. G. Synlett 2010, 166.
MHz, CDCl3): δ = 33.0 (Me), 37.8 (NMe2), 90.4 (CCl3),
110.1 (C), 122.6 (C), 128.7 (2 CH), 129.2 (CH), 132.5 (2
CH), 163.0 (C), 167.0 (C), 170.0 (C). MS: m/z (%) = 409 (1)
[M+], 363 (11), 330 (14), 329 (18), 314 (17), 116 (31), 94
(100), 78 (54), 77 (32), 44 (22). Anal. Calcd (%) for
C14H15Cl3N4O2S (409.72): C, 41.04; H, 3.69; N, 13.67.
Found: C, 41.42; H, 3.76; N, 13.52.
(11) Hein, J. E.; Fokin, V. V. Chem. Soc. Rev. 2010, 39, 1302.
(12) Yoo, E. J.; Chang, S. Curr. Org. Chem. 2009, 13, 1766.
(13) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K.
B. Angew. Chem. Int. Ed. 2002, 41, 2596.
(14) Tornøe, C. W.; Christensen, C.; Meldal, M. J. Org. Chem.
2002, 67, 3057.
(15) Jin, H.; Zhou, B.; Wu, Z.; Shen, Y.; Wang, Y. Tetrahedron
2011, 67, 1178.
(16) Yavari, I.; Nematpour, M. Synlett 2012, 23, 2215.
(17) Yavari, I.; Nematpour, M.; Yavari, S.; Sadeghizadeh, F.
Tetrahedron Lett. 2012, 53, 1889.
N-[6-(Dimethylamino)-5-propyl-2-(trichloromethyl)-
pyrimidin-4-yl]-4-methylbenzenesulfonamide (5d)
Cream powder; mp 113–115 °C; yield 0.29 g (65%). IR
(KBr): νmax = 3039, 1633, 1590, 1368, 1218, 1018, 751 cm–
1. 1H NMR (500 MHz, CDCl3): δ = 0.96 (3 H, t, 3J = 6.8 Hz,
Me), 1.48–1.55 (2 H, m, CH2), 2.13 (2 H, t, 3J = 6.8 Hz,
CH2), 2.45 (3 H, s, Me), 3.07 (6 H, s, NMe2), 7.38 (2 H, d, 3J
= 7.9 Hz, Ar), 7.89 (2 H, d, 3J = 7.9 Hz, Ar), 8.21 (1 H, s,
NH). 13C NMR (125.7 MHz, CDCl3): δ = 13.7 (Me), 20.8
(CH2), 22.3 (CH2), 33.3 (Me), 38.6 (NMe2), 90.4 (CCl3),
111.0 (C), 127.4 (2 CH), 129.6 (2 CH), 142.1 (C), 147.3 (C),
164.7 (C), 168.6 (C), 170.0 (C). MS: m/z (%) = 450 (1) [M+],
406 (11), 391 (8), 343 (14), 280 (17), 170 (21), 155 (100),
116 (31), 91 (45), 44 (20), 43 (30). Anal. Calcd (%) for
C17H21Cl3N4O2S (450.05): C, 45.19; H, 4.68; N, 12.40.
Found: C, 45.54; H, 4.55; N, 12.51.
(18) Yavari, I.; Nematpour, M. Mol. Diversity 2012, 16, 651.
(19) Typical Procedure for the Preparation of Compounds 5
Compounds 3 (1 mmol) and 4 (1 mmol) were dissolved in
MeCN (2 mL) and stirred for 30 min. Then, a mixture of
sulfonyl azide 2 (1.2 mmol), alkyne 1 (1 mmol), CuI (0.1
mmol), and Et3N (1 mmol) in MeCN (3 mL) was slowly
added to the mixture and stirred at r.t. under N2 atmosphere.
After completion of the reaction [about 8 h; TLC (EtOAc–
hexane = 1:5) monitoring], the mixture was diluted with
CH2Cl2 (2 mL) and aq NH4Cl solution (3 mL), stirred for 30
min, and the layers were separated. The aqueous layer was
extracted with CH2Cl2 (3 × 3 mL). The combined organic
fractions were dried (Na2SO4) and concentrated under
reduced pressure. The residue was purified by flash column
chromatography [silica gel (230–400 mesh; Merck),
hexane–EtOAc = 5:1] to give the product.
N-[6-(Dimethylamino)-5-propyl-2-(trichloromethyl)-
pyrimidin-4-yl]benzenesulfonamide (5e)
Cream powder; mp 100–103 °C; yield 0.27 g (63%). IR
(KBr): νmax = 3061, 1680, 1571, 1435, 1377, 1235, 1163,
1075, 748 cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.97 (3 H,
t, 3J = 6.8 Hz, Me), 1.48–1.56 (2 H, m, CH2), 2.12 (2 H, t, 3J
= 6.8 Hz, CH2), 3.10 (6 H, s, NMe2), 7.60 (2 H, t, 3J = 7.8 Hz,
Ar), 7.74 (1 H, t, 3J = 7.8 Hz, Ar), 8.00 (2 H, d, 3J = 7.8 Hz,
Ar), 8.24 (1 H, s, NH). 13C NMR (125.7 MHz, CDCl3): δ =
13.7 (Me), 20.8 (CH2), 22.4 (CH2), 38.7 (NMe2), 91.0
(CCl3), 110.6 (C), 127.3 (2 CH), 130.1 (2 CH), 135.7 (CH),
144.8 (C), 164.8 (C), 168.9 (C), 171.0 (C). MS: m/z (%) =
436 (1) [M+], 392 (15), 319 (13), 296 (21), 280 (17), 156
(45), 144 (100), 116 (35), 77 (49), 44 (25), 43 (22). Anal.
Calcd (%) for C16H19Cl3N4O2S (436.03): C, 43.90; H, 4.37;
N, 12.80. Found: C, 44.21; H, 4.48; N, 12.91.
N-[6-(Dimethylamino)-5-phenyl-2-(trichloromethyl)-
pyrimidin-4-yl]-4-methylbenzenesulfonamide (5a)
Cream powder; mp 159–161 °C; yield 0.40 g (83%). IR
(KBr): νmax = 3061, 1682, 1590, 1445, 1375, 1172, 1071, 754
cm–1. 1H NMR (500 MHz, CDCl3): δ = 2.87 (3 H, s, Me),
2.95 (6 H, s, NMe2), 7.07 (2 H, d, 3J = 7.4 Hz, Ar), 7.18 (1
H, t, 3J = 7.4 Hz, Ar), 7.28 (2 H, t, 3J = 7.4 Hz, Ar), 7.39 (2
H, d, 3J = 7.9 Hz, Ar), 7.91 (2 H, d, 3J = 7.9 Hz, Ar), 8.03 (1
H, s, NH). 13C NMR (125.7 MHz, CDCl3): δ = 32.4 (Me),
37.5 (NMe2), 90.4 (CCl3), 110.0 (C), 122.5 (C), 127.4 (2
CH), 128.7 (2 CH), 129.2 (CH), 130.7 (2 CH), 132.5 (2 CH),
142.1 (C), 147.3 (C), 163.6 (C), 168.9 (C), 171.0 (C). MS:
m/z (%) = 484 (1) [M+], 439 (6), 406 (12), 392 (16), 367 (21),
170 (23), 155 (100), 116 (43), 91 (70), 77 (51), 44 (31). Anal.
Calcd (%) for C20H19Cl3N4O2S (484.03): C, 49.45; H, 3.94;
N, 11.53. Found: C, 49.68; H, 4.02; N, 11.62.
N-[6-(Dimethylamino)-5-propyl-2-(trichloromethyl)-
pyrimidin-4-yl]methanesulfonamide (5f)
Cream powder; mp 90–93 °C; yield 0.22 g (60%). IR (KBr):
ν
max = 3064, 1679, 1565, 1459, 1370, 1271, 1180, 1049, 749
cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.99 (3 H, t, 3J = 6.8
Hz, Me), 1.49–1.57 (2 H, m, CH2), 2.14 (2 H, t, 3J = 6.8 Hz,
CH2), 2.96 (6 H, s, NMe2), 3.56 (3 H, s, Me), 8.28 (1 H, s,
NH). 13C NMR (125.7 MHz, CDCl3): δ = 13.7 (Me), 20.8
(CH2), 22.3 (CH2), 33.0 (Me), 39.7 (NMe2), 90.4 (CCl3),
111.0 (C), 165.6 (C), 167.7 (C), 170.0 (C). MS: m/z (%) =
374 (1) [M+], 330 (11), 329 (9), 295 (25), 280 (13), 116 (30),
94 (100), 78 (39), 44 (29), 43 (26). Anal. Calcd (%) for
C11H17Cl3N4O2S (374.01): C, 35.17; H, 4.56; N, 14.91.
Found: C, 35.40; H, 4.63; N, 15.03.
N-[6-(Dimethylamino)-5-phenyl-2-(trichloromethyl)-
pyrimidin-4-yl]benzenesulfonamide (5b)
Cream powder; mp 167–170 °C; yield 0.40 g (87%). IR
(KBr): νmax = 3060, 1681, 1595, 1441, 1373, 1270, 1182,
1072, 750 cm–1. 1H NMR (500 MHz, CDCl3): δ = 2.96 (6 H,
s, NMe2), 7.25–7.31 (3 H, m, Ph), 7.45 (2 H, d, 3J = 7.4 Hz,
Ar), 7.58 (2 H, t, 3J = 7.4 Hz, Ar), 7.69 (1 H, t, 3J = 7.9 Hz,
Ar), 8.00 (2 H, d, 3J = 7.9 Hz, Ar), 8.07 (1 H, s, NH). 13
C
NMR (125.7 MHz, CDCl3): δ = 37.5 (NMe2), 90.4 (CCl3),
110.3 (C), 122.5 (C), 127.4 (2 CH), 128.7 (2 CH), 129.2
(CH), 130.2 (2 CH), 132.5 (2 CH), 135.7 (CH), 144.8 (C),
163.6 (C), 167.8 (C), 171.1 (C). MS: m/z (%) = 470 (1) [M+],
425 (3), 392 (21), 314 (17), 156 (31), 141 (100), 91 (71), 77
(50), 44 (31). Anal. Calcd (%) for C19H17Cl3N4O2S (470.01):
C, 48.37; H, 3.63; N, 11.88. Found: C, 48.63; H, 3.69; N,
12.01.
N-[5-Butyl-6-(dimethylamino)-2-(trichloromethyl)-
pyrimidin-4-yl]-4-methylbenzenesulfonamide (5g)
Cream powder; mp 119–122 °C; yield 0.28 g (60%). IR
(KBr): νmax = 3032, 1627, 1551, 1450, 1365, 1222, 1177,
1079, 739 cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.92 (3 H,
t, 3J = 6.8 Hz, Me), 1.36–1.43 (2 H, m, CH2), 1.46–1.51 (2
H, m, CH2), 2.14 (2 H, t, 3J = 6.8 Hz, CH2), 2.50 (3 H, s, Me),
3.00 (6 H, s, NMe2), 7.39 (2 H, d, 3J = 8.0 Hz, Ar), 7.92 (2
H, d, 3J = 8.0 Hz, Ar), 8.30 (1 H, s, NH). 13C NMR (125.7
MHz, CDCl3): δ = 13.9 (Me), 18.5 (CH2), 21.8 (CH2), 22.2
(CH2), 33.8 (Me), 39.3 (NMe2), 90.4 (CCl3), 110.1 (C),
127.5 (2 CH), 129.6 (2 CH), 142.0 (C), 147.3 (C), 163.7 (C),
169.0 (C), 172.0 (C). MS: m/z (%) = 464 (1) [M+], 420 (8),
406 (11), 347 (13), 170 (21), 155 (100), 116 (50), 91 (42), 57
N-[6-(Dimethylamino)-5-phenyl-2-(trichloromethyl)-
pyrimidin-4-yl]methanesulfonamide (5c)
Cream powder; mp 123–125 °C; yield 0.32 g (79%). IR
(KBr): νmax = 3031, 1684, 1592, 1446, 1361, 1278, 1170,
1073, 757 cm–1. 1H NMR (500 MHz, CDCl3): δ = 2.93 (6 H,
s, NMe2), 3.65 (3 H, s, Me), 7.25–7.35 (3 H, m, Ph), 7.48 (2
H, d, 3J = 7.4 Hz, Ar), 8.11 (1 H, s, NH). 13C NMR (125.7
© Georg Thieme Verlag Stuttgart · New York
Synlett 2013, 24, 165–168

168
I. Yavari, M. Nematpour
LETTER
N-[5-Butyl-6-(dimethylamino)-2-(trichloromethyl)-
(44), 44 (45). Anal. Calcd (%) for C18H23Cl3N4O2S (464.06):
C, 46.41; H, 4.98; N, 12.03. Found: C, 46.67; H, 5.07; N,
12.16.
N-[5-Butyl-6-(dimethylamino)-2-(trichloromethyl)-
pyrimidin-4-yl]benzenesulfonamide (5h)
pyrimidin-4-yl]methanesulfonamide (5i)
Cream powder; mp 95–98 °C; yield 0.20 g (52%). IR (KBr):
ν
max = 3030, 1669, 1582, 1451, 1376, 1179, 1078, 741 cm–1.
1H NMR (500 MHz, CDCl3): δ = 0.89 (3 H, t, 3J = 6.8 Hz,
Me), 1.34–1.40 (2 H, m, CH2), 1.44–1.52 (2 H, m, CH2),
2.14 (2 H, t, 3J = 6.8 Hz, CH2), 2.96 (6 H, s, NMe2), 3.46 (3
H, s, Me), 8.24 (1 H, s, NH). 13C NMR (125.7 MHz, CDCl3):
δ = 13.9 (Me), 18.4 (CH2), 20.8 (CH2), 22.7 (CH2), 33.6
(Me), 38.3 (NMe2), 90.1 (CCl3), 111.0 (C), 165.8 (C), 167.9
(C), 171.3 (C). MS: m/z (%) = 388 (1) [M+], 343 (8), 315
(10), 294 (22), 279 (25), 116 (23), 94 (100), 78 (23), 44 (43).
Anal. Calcd (%) for C12H19Cl3N4O2S (388.03): C, 36.98; H,
4.91; N, 14.38. Found: C, 37.29; H, 4.85; N, 14.47.
(20) Yoo, E. J.; Ahlquist, M.; Kim, S. H.; Bae, I.; Fokin, V. V.;
Sharpless, K. B.; Chang, S. Angew. Chem. Int. Ed. 2007, 46,
1730.
Cream powder; mp 111–114 °C; yield 0.26 g (57%). IR
(KBr): νmax = 3031, 1613, 1592, 1451, 1376, 1220, 1177,
1079, 743 cm–1. 1H NMR (500 MHz, CDCl3): δ = 0.88 (3 H,
t, 3J = 6.8 Hz, Me), 1.35–1.41 (2 H, m, CH2), 1.43–1.50 (2
H, m, CH2), 2.13 (2 H, t, 3J = 6.8 Hz, CH2), 2.96 (6 H, s,
NMe2), 7.61 (2 H, t, 3J = 7.8 Hz, Ar), 7.71 (1 H, t, 3J = 7.8
Hz, Ar), 7.99 (2 H, d, 3J = 7.8 Hz, Ar), 8.18 (1 H, s, NH). 13
C
NMR (125.7 MHz, CDCl3): δ = 13.9 (Me), 18.4 (CH2), 20.8
(CH2), 22.2 (CH2), 38.3 (NMe2), 90.1 (CCl3), 111.4 (C),
127.3 (2 CH), 130.2 (2 CH), 135.7 (CH), 144.8 (C), 164.3
(C), 169.0 (C), 171.0 (C). MS: m/z (%) = 450 (1) [M+], 406
(6), 392 (10), 373 (22), 294 (25), 156 (100), 141 (23), 116
(50), 57 (41), 44 (22). Anal. Calcd (%) for C17H21Cl3N4O2S
(450.05): C, 45.19; H, 4.68; N, 12.40. Found: C, 45.52; H,
4.71; N, 12.52.
(21) Cassidy, M. P.; Raushel, J.; Fokin, V. V. Angew. Chem. Int.
Ed. 2006, 45, 3154.
(22) Yoo, E. J.; Ahlquist, M.; Bae, I.; Sharpless, K. B.; Fokin, V.
V.; Chang, S. J. Org. Chem. 2008, 73, 5520.
Synlett 2013, 24, 165–168
© Georg Thieme Verlag Stuttgart · New York