Novel Catalytic Three-Component Reaction between a Terminal Alkyne, Sulfonyl Azide, and O -Methyl Oxime

Article abstract of DOI:10.1055/s-0036-1588989

O -Methyl oximes have been employed as nucleophiles in reactions with ketenimines derived from sulfonyl azides and terminal alkynes to form N -alkylidene N ′-tosylacetimidamide derivatives. The optimized conditions involved the use of CuPF ₆ and i -Pr ₂ NEt in MeCN at 65 °C. Both O -methyl aldoximes and ketoximes were tolerated under the optimum conditions.

Full text of DOI:10.1055/s-0036-1588989

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© Georg Thieme Verlag Stuttgart · New York
2017, 28, A–D
letter
A
en
M. Khalaj et al.
Letter
Synlett
Novel Catalytic Three-Component Reaction between a Terminal
Alkyne, Sulfonyl Azide, and O-Methyl Oxime
Mehdi Khalaj*a
R2
R1
N
O
Majid Ghazanfarpour-Darjania
Forugh Barat-Seftejanib
Azita Nourib
OMe
N
1. CuPF6, MeCN, DIEA
R1
R2N3
+
R3
+
N
H
2. B(C6F5)3, KOH
5–75 °C, 24–28 h
R3
12 examples
Yield: 65–90%
a Department of Chemistry, Buinzahra Branch, Islamic Azad
University, Buinzahra, Iran
b Department of Chemistry, Shahr-e-Qods Branch, Islamic Azad
University, Tehran, Iran
khalaj_mehdi@yahoo.com
Received: 27.01.2017
Accepted after revision: 08.03.2017
Published online: 10.04.2017
the preparation of α-sulfonylimino carboxamides.20 On the
basis of these findings and in continuation of our interest in
catalytic methodologies,21–23 we have examined the effica-
cy of O-methyl oximes as potential nucleophiles in reac-
tions with ketenimines. Here, we describe a novel pathway
DOI: 10.1055/s-0036-1588989; Art ID: st-2017-d0070-l
Abstract O-Methyl oximes have been employed as nucleophiles in re-
actions with ketenimines derived from sulfonyl azides and terminal
alkynes to form N-alkylidene N′-tosylacetimidamide derivatives. The
optimized conditions involved the use of CuPF6 and i-Pr2NEt in MeCN at
65 °C. Both O-methyl aldoximes and ketoximes were tolerated under
the optimum conditions.
Table 1 Optimization of the Reaction Conditionsa
Ts
Ph
OMe
N
O
1. catalyst, base, solvent
N
Ph
+
+
TsN3
N
Ph
Ph
Key words ketenimines, alkynes, sulfonyl azides, oximes, multicom-
ponent reactions, copper catalysis
2. B(C6F5)3, KOH
65 °C, 24 h
H
1a
2a
4a
3a
Entry
Catalyst
Solvent
Yield (%)
Transition-metal-catalyzed multicomponent reactions
have attracted much attention because they exhibit excel-
lent catalytic efficiency in most cases.1,2 Since the introduc-
tion of the term ‘click chemistry’ by Sharpless, Meldal, and
their respective co-workers,3,4 Huisgen’s terminal alkyne–
azide 1,3-cycloaddition has been well developed, and hun-
dreds of papers having appeared describing the use of this
simple click method.5–8 Copper-catalyzed reactions involv-
ing the use of electron-deficient azides and alkynes to gen-
erate ketenimine intermediates have drawn special interest
because such intermediates are useful in the preparation of
a range of functionalities and heterocyclic compounds.9–13
It should be noted that ketenimine itself was first described
and prepared by Staudinger and Hauser in 1921.14 Chang
and co-workers reported several CuI-catalyzed multicom-
ponent reactions of sulfonyl azides with alkynes, amines,
water, or imines to give N-sulfonylamidines and N-sulfo-
nylazetidin-2-imines.15–18 Yavari et al. reported a novel syn-
thesis of substituted N-tosylacetoyloxyimines through a
CuI-catalyzed multicomponent reaction of sulfonyl azides
with alkynes and oximes.19 They also described an interest-
ing reaction between sulfonyl azides, alkynes, and isocya-
nides in the presence of CuI, providing a useful method for
1
2
CuPF6
CuBr
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
DMF
79
14
3
CuCl
42
4
CuI
37
5
CuCl2
Cu2O
Cu(OAc)2
CuBF4
CuOTf
CuPF6
CuPF6
CuPF6
CuPF6
CuPF6
CuPF6
CuPF6
trace
25
6
7
–
8
49
9
54
10
11
12
13
14
15
16
71
DMSO
CHCl3
1,4-dioxane
THF
65
11
43
49
toluene
MeCN
trace
trace
a Reaction conditions: 1a (1.0 mmol), 2a (1.2 mmol), 3a (4.0 mmol), i-Pr2NEt
(1.0 mmol), catalyst (0.1 mmol), solvent (3 mL), stirring, 65 °C, 18 h, then
B(C6F5)3 (1.0 mmol), KOH (2.0 mmol), 4:1 H2O–1,4-dioxane (5 mL), 75 °C,
6 h, under N2, sealed tube.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–D

B
M. Khalaj et al.
Letter
Synlett
for the synthesis of α-sulfonylimino amide derivatives
through a copper-catalyzed three-component reaction of
sulfonyl azides, 1-alkynes, and O-methyl oximes.
solvents gave the desired product in moderate yields (en-
tries 13 and 14). The apolar solvent toluene was not effi-
cient (entry 15). Inorganic bases such as K3PO4 and K2CO3 or
conventional monodentate nitrogen bases such as Et3N or
pyridine failed to improve the yield of the product.
We initially examined the reaction of ethynylbenzene
(1a) with p-toluenesulfonyl azide (2a) and benzaldehyde O-
methyl oxime (3a) in the presence of CuI and i-Pr2NEt as a
model reaction to assess the reaction efficiency. The reac-
tion mixture was stirred in THF at 65 °C for 18 hours. When
the reaction was complete [TLC, hexane–EtOAc (2:1)], the
solvent was removed under reduced pressure and the crude
mixture was treated with B(C6F5)3 and KOH in aqueous 1,4-
dioxane at 75 °C in a sealed tube. After six hours, N-(2-phe-
nyl-N-tosylethanimidoyl)benzamide (4a) was formed in
21% yield.
To improve this yield, a variety of catalysts and solvents
were examined (Table 1). The catalyst screen showed that
CuPF6 gave the best result (Table 1, entry 1); other copper
salts also promoted the reaction, but with lower yields (en-
tries 2–6). Cu(I) prepared in situ from Cu(OAc)2 and sodium
ascorbate in t-BuOH–H2O did not promote the desired
transformation, but instead gave 2-phenyl-N-tosylacet-
amide in high yield (entry 7). Reactions conducted with
CuOTf or CuBF4 led to moderate conversions (entries 8 and
9). Among the solvents examined, MeCN was superior to
other solvents (entry 1). Reactions conducted in polar
aprotic solvents such as DMF or DMSO proceeded in accept-
able yields (entries 10 and 11), but a chlorinated solvent
gave the desired product in low yield (entry 12), and ether
We next sought to explore the scope of the reaction (Ta-
ble 2).24 The reactions of electron-neutral oximes such as 3a
proceeded in acceptable yields (Table 2, entries 1 and 2).
Reactions conducted with 4-methoxy and 4- or 3-methyl-
benzaldehyde O-methyl oximes proceeded in good yields,
but required longer reaction times (entries 3–5). Notably,
the tolerance to bromo or chloro substituents on the aro-
matic ring (entries 6 and 7) provides an opportunity for
subsequent cross-coupling reactions. Electron-deficient
substrates afforded lower yields of product (entries 8 and 9)
than did electron-neutral or electron-rich substrates, prob-
ably due to the lower nucleophilicity of the oxime moiety.
Aliphatic terminal alkynes afforded the desired products in
lower yields than did ethynylbenzene, probably due to the
lower acidities of these substrates (entries 10–12). Aliphatic
oximes were not compatible with this transformation.
A mechanistic rationalization for the reaction is given in
Scheme 1. The initial event is the formation of a copper
acetylide, which undergoes a 1,3-dipolar cycloaddition
with the sulfonyl azide 2. The resulting intermediate is con-
verted into the ketenimine 5, which is subsequently trans-
formed into intermediate 6 through attack by oxime 3. Pro-
Table 2 Reaction Scopea
R2
R1
OMe
N
O
N
1. CuPF6, MeCN, DIEA
R1
R2N3
2
+
R3
+
N
R3
H
2. B(C6F5)3, KOH, 65 °C
24 h
1
4
3
Entry
Alkyne
R1
Ph
Azide
R2
Ts
Oxime
R3
Product
Yield (%)
1
2
1a
1a
1a
1a
1a
1a
1a
1a
1a
1b
1c
1d
2a
2b
2a
2b
2b
2b
2b
2b
2b
2b
2b
2b
3a
Ph
Ph
4a
4b
4c
4d
4e
4f
79
76
90
85
84
76
79
69b
67b
70
71
65
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Pr
PhSO2
PhSO2
Ts
3a
3b
3c
3d
3e
3e
3f
3
4-MeOC6H4
4-MeC6H4
3-MeC6H4
4-ClC6H4
4-BrC6H4
3-F3CC6H4
4-MeO2CC6H4
Ph
4
5
Ts
6
Ts
7
Ts
4g
4h
4i
8
Ts
9
Ts
3g
3b
3b
3b
10
11
12
Ts
4j
Bu
TMS
Ts
Ph
4k
4l
Ts
Ph
a Reaction conditions: 1 (1.0 mmol), 2 (1.2 mmol), 3 (4.0 mmol), i-Pr2NEt (1.0 mmol), CuPF6 (0.1 mmol), MeCN (3 mL), stirring, 65 °C, 18 h, then B(C6F5)3 (0.3
mmol), KOH (2.0 mL), 4:1 H2O–1,4-dioxane, 75 °C, 6 h, under N2, sealed tube.
b Stirred at 75 °C for 22 h (step 1).
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–D

C
M. Khalaj et al.
Letter
Synlett
ton abstraction from 7 in an E2-like reaction induced by the
action of B(C6F5)3 affords 8. Finally, aqueous workup con-
verts intermediate 8 into product 4.
(20) Yavari, I.; Ghazanfarpour-Darjani, M.; Nematpour, M. Tetrahe-
dron Lett. 2015, 56, 2416.
(21) Khalaj, M.; Ghazanfarpour-Darjani, M. RSC Adv. 2015, 5, 80698.
(22) Ghazanfarpour-Darjani, M.; Babapour-Kooshalshahi, M.;
Mousavi-Safavi, S. M.; Akbari-Neyestani, J.; Khalaj, M. Synlett.
2016, 27, 259.
(23) Ghazanfarpour-Darjani, M.; Khodakarami, A. Monatsh. Chem.
2016, 147, 829.
(24) N-[N-(Arylsulfonyl)imidoyl]benzamides 4a–l; General Proce-
dure
OMe
N
R1
NSO2R2
N
Cu
R1
R3
3
CuPF6, MeCN
DIEA
R1
NR2
⋅
+ R2N3
R3
OMe
6
5
1
2
i-Pr2NEt (1.0 mL) was slowly added to a stirred solution of the
appropriate terminal alkyne (1.0 mmol), sulfonyl azide (1.2
mmol), and CuPF6 (0.10 mmol) in MeCN (3 mL) under N2 at r.t.
After 15 min, the appropriate O-methyl oxime (4.0 mmol) was
added, and the mixture was stirred in a sealed tube for 18 h (see
Table 2) at 65–75 °C. The solvent was removed under vacuum
and the residue was treated with B(C6F5)3 (0.3 mmol) and KOH
(2.0 mmol) in 4:1 H2O–1,4-dioxane (10 mL) at 75 °C for 6 h.
EtOAc (5 mL) and sat. aq NH4Cl (5 mL) were added, the mixture
was stirred for an additional 30 min, and the two layers were
separated. The aqueous layer was further extracted with EtOAc
(3 × 10 mL), and the organic layers were combined, dried (Na2-
SO4), filtered, and concentrated under vacuum. The residue was
purified by chromatography [silica gel, hexane–EtOAc (2:1)]
N-(2-Phenyl-N-tosylethanimidoyl)benzamide (4a)
Colorless solid; yield: 0.31 g (79%); mp 147–149 °C. IR (KBr):
3241, 1671, 1548, 1510, 1432, 1325, 1110 cm–1. 1H NMR (500.1
MHz, CDCl3): δ = 2.47 (s, 3 H, CH3), 3.89 (s, 2 H, CH2), 7.19 (t,
3J = 6.3 Hz, 1 H, CH), 7.26–7.33 (m, 6 H, 6 CH), 7.43–7.67 (m, 5 H,
5 CH), 7.87 (d, 3J = 7.6 Hz, 2 H, 2 CH), 10.78 (s, 1 H, NH). 13C NMR
(125.7 MHz, CDCl3): δ = 21.5 (CH3), 44.9 (CH2), 126.5 (2 CH),
126.8 (CH), 127.4 (2 CH), 128.1 (2 CH), 128.4 (2 CH), 129.4 (2
CH), 130.1 (2 CH), 133.7 (CH), 134.1 (C), 135.1 (C), 140.3 (C),
142.5 (C), 159.1 (CH), 169.3 (C). MS: m/z (%) = 392 (M+, 5), 271
(13), 140 (17), 104 (23), 91 (100), 77 (492), 64 (40). Anal. Calcd
for C22H20N2O3S (392.47): C, 67.33; H, 5.14; N, 7.14; S, 8.17.
Found: C, 67.61; H, 5.37; N, 7.22; S, 8.13.
NR2
OH
R3
NR2
H
B(C6F5)3, KOH
R1
aqueous workup
H2O, NH4Cl
R1
N
N
R3
OMe
8
(C6F5)3B
7
R2
N
O
R1
N
R3
H
4
Scheme 1 Plausible reaction mechanism
In summary, we have developed a new catalytic multi-
component reaction for the synthesis of tosylimino amide
derivatives that uses readily available sulfonyl azides, ter-
minal alkynes, and O-methyl oximes. Further studies are
being conducted to develop the scope of the reaction and to
elucidate its mechanistic pathway.
References and Notes
(1) Hulme, C.; Gore, V. Curr. Med. Chem. 2003, 10, 51.
(2) Tuch, A.; Wallé, S. In Handbook of Combinatorial Chemistry:
Drugs, Catalysts, Materials;
2
V
o.
l
Nicolaou, K. C.; Hanko, R.; Hartwig,
W. Chap. 23; Wiley-VCH: Weinheim, 2002, 685.
(3) Rostovtsev, V. V.; Green, L. G.; Fokin, V. V.; Sharpless, K. B.
Angew. Chem. Int. Ed. 2002, 41, 2596.
N-[2-Phenyl-N-(phenylsulfonyl)ethanimidoyl]benzamide
(4b)
Colorless solid; yield: 0.29 g (76%); mp 140–142 °C. IR (KBr):
3256, 1662, 1541, 1522, 1417, 1331, 1124 cm–1. 1H NMR (500.1
MHz, CDCl3): δ = 3.87 (s, 2 H, CH2), 7.19–7.31 (m, 5 H, 5 CH),
7.51–7.64 (m, 5 H, 5 CH), 7.71–7.78 (m, 3 H, 3 CH), 7.89 (d,
3J = 6.9 Hz, 2 H, 2 CH), 10.71 (s, 1 H, NH). 13C NMR (125.7 MHz,
CDCl3): δ = 45.1 (CH2), 123.3 (CH), 124.9 (2 CH), 126.5 (2 CH),
128.7 (2 CH), 129.1 (2 CH), 129.9 (2 CH), 131.5 (2 CH), 133.6
(CH), 133.9 (C), 134.5 (CH), 136.1 (C), 145.7 (C), 159.4 (C), 170.1
(C). MS: m/z (%) = 378 (M+, 1), 273 (11), 156 (34), 121 (21), 91
(100), 77 (63), 64 (41). Anal. Calcd for C21H18N2O3S (378.45): C,
66.65; H, 4.79; N, 7.40; S, 8.47. Found: C, 66.83; H, 4.91; N, 7.53;
S, 8.59.
(4) Tornøe, C. W.; Christensen, C.; Meldal, M. J. Org. Chem. 2002, 67,
3057.
(5) Amblard, F.; Cho, J. H.; Schinazi, R. F. Chem. Rev. 2009, 109, 4207.
(6) Meldal, M.; Tornøe, C. W. Chem. Rev. 2008, 108, 2952.
(7) Lu, P.; Wang, Y. Synlett 2010, 165.
(8) Boren, B. C.; Narayan, S.; Rasmussen, L. K.; Zhang, L.; Zhao, H.;
Lin, Z.; Jia, G.; Fokin, V. V. J. Am. Chem. Soc. 2008, 130, 8923.
(9) Zhang, D.; Nakamura, I.; Terada, M. Org. Lett. 2014, 16, 5184.
(10) Yao, B.; Shen, C.; Liang, Z.; Zhang, Y. J. Org. Chem. 2014, 79, 936.
(11) Xu, H.-D.; Jia, Z.-H.; Xu, K.; Han, M.; Jiang, S.-N.; Cao, J.; Wang, J.-
C.; Shen, M.-H. Angew. Chem. Int. Ed. 2014, 53, 9284.
(12) Yang, T.; Cui, H.; Zhang, C.; Zhang, L.; Su, C.-Y. Inorg. Chem. 2013,
52, 9053.
(13) Xing, Y.; Cheng, B.; Wang, J.; Lu, P.; Wang, Y. Org. Lett. 2014, 16,
4814.
(14) Staudinger, H.; Hauser, E. Helv. Chim. Acta 1921, 4, 887.
(15) Bae, I.; Han, H.; Chang, S. J. Am. Chem. Soc. 2005, 127, 2038.
(16) Cho, S. H.; Yoo, E. J.; Bae, I.; Chang, S. J. Am. Chem. Soc. 2005, 127,
16046.
(17) Cho, S. H.; Chang, S. Angew. Chem. Int. Ed. 2007, 46, 1897.
(18) Cho, S. H.; Chang, S. Angew. Chem. Int. Ed. 2008, 47, 2836.
(19) Yavari, I.; Ghazanfarpour-Darjani, M.; Bayat, M. J.; Malekafzali,
A. Synlett 2014, 25, 959.
4-Methoxy-N-[2-phenyl-N-(phenylsulfonyl)ethanimi-
doyl]benzamide (4c)
Colorless solid; yield: 0.37 g (90%); mp 170–172 °C. IR (KBr):
3240, 1658, 1560, 1532, 1428, 1320, 1140 cm–1. 1H NMR (500.1
MHz, CDCl3): δ = 3.85 (s, 2 H, CH2), 3.89 (s, 3 H, OCH3), 6.95
(app. d, 3J = 7.5 Hz, 2 H, 2 CH), 7.19–7.27 (m, 5 H, 5 CH), 7.69–
7.76 (m, 5 H, 5 CH), 7.84 (app. d, 3J = 7.5 Hz, 2 H, 2 CH), 10.68 (s,
1 H, NH). 13C NMR (125.7 MHz, CDCl3): δ = 46.2 (CH2), 57.1
(OCH3), 115.1 (2 CH), 125.2 (2 CH), 126.1 (CH), 126.8 (2 CH),
127.1 (C), 129.1 (2 CH), 130.4 (2 CH), 131.2 (2 CH), 134.0 (CH),
136.7 (C), 147.1 (C), 158.1 (C), 161.8 (C), 169.5 (C). MS: m/z
(%) = 408 (M+, 1), 268 (11), 258 (17), 150 (57), 91 (100), 77 (67),
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–D

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M. Khalaj et al.
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64 (35). Anal. Calcd for C22H20N2O4S (408.47): C, 64.69; H, 4.94;
N, 6.86; S, 7.85. Found: C, 64.86; H, 5.31; N, 6.93; S, 7.91.
4-Bromo-N-[2-phenyl-N-(tosyl)ethanimidoyl]benzamide
(4g)
(358.46): C, 63.66; H, 6.19; N, 7.82; S, 8.94. Found: C, 63.85; H,
6.34; N, 7.98; S, 9.17.
N-(N-Tosylhexanimidoyl)benzamide (4k)
Colorless solid; yield: 0.26 g (71%); mp 138–140 °C. IR (KBr):
3273, 1663, 1543, 1458, 1337, 1129 cm–1. 1H NMR (500.1 MHz,
CDCl3): δ = 0.83 (t, 3J = 6.9 Hz, 3 H, CH3), 1.37–1.65 (m, 6 H, 3
CH2), 2.32 (s, 3 H, CH3), 2.61 (t, 3J = 7.6 Hz, 2 H, CH2), 7.27 (d,
3J = 6.9 Hz, 2 H, 2 CH), 7.49 (d, 3J = 6.9 Hz, 2 H, 2 CH), 7.60–7.65
(m, 3 H, 3 CH), 8.02 (d, 3J = 6.5 Hz, 2 H, 2 CH), 10.62 (s, 1 H, NH).
13C NMR (125.7 MHz, CDCl3): δ = 13.2 (CH3), 22.1 (CH2), 22.8
(CH2), 24.0 (CH2), 24.7 (CH3), 33.5 (CH2), 126.2 (2 CH), 128.0 (2
CH), 129.3 (2 CH), 131.1 (2 CH), 133.0 (CH), 134.1 (C), 141.2 (C),
143.6 (C), 159.5 (C), 168.2 (C). MS: m/z (%) = 372 (M+, 1), 252
(16), 172 (59), 120 (68), 105 (100), 77 (60). Anal. Calcd for
Colorless solid; yield: 0.37 g (79%); mp 181–183 °C. IR (KBr):
3236, 1657, 1549, 1532, 1420, 1317, 1140 cm–1. 1H NMR (500.1
MHz, CDCl3): δ = 2.41 (s, 3 H, CH3), 3.82 (s, 2 H, CH2), 7.20–7.31
(m, 7 H, 7 CH), 7.51 (d, 3J = 7.7 Hz, 2 H, 2 CH), 7.76 (d, 3J = 7.8 Hz,
2 H, 2 CH), 7.91 (d, 3J = 7.8 Hz, 2 H, 2 CH), 10.76 (1 H, s, NH). 13
C
NMR (125.7 MHz, CDCl3): δ = 23.9 (CH3), 44.0 (CH2), 125.5 (C),
125.9 (2 CH), 126.1 (CH), 127.5 (2 CH), 128.2 (2 CH), 128.9 (2
CH), 130.3 (2 CH), 132.7 (2 CH), 133.5 (C), 134.9 (C), 140.3 (C),
141.7 (C), 159.2 (C), 169.3 (C). MS: m/z (%) = 473 [M + 2]+ (6),
471 (M+, 6), 272 (13), 197 (57), 182 (68), 171 (39), 91 (100).
Anal. Calcd for C22H19BrN2O3S (471.37): C, 56.06; H, 4.06; N,
5.94; Br, 16.95; S, 6.80. Found: C, 56.34; H, 4.37; N, 6.11; Br,
17.21; S, 6.97.
C
20H24N2O3S (372.48): C, 64.49; H, 6.49; N, 7.52; S, 8.61. Found:
C, 64.63; H, 6.49; N, 7.76; S, 8.81.
N-[N-Tosyl-2-(trimethylsilyl)ethanimidoyl]benzamide (4l)
Colorless solid; yield: 0.25 g (65%); mp 121–123 °C. IR (KBr):
3258, 1654, 1561, 1448, 1337, 1106 cm–1. 1H NMR (500.1 MHz,
CDCl3): δ = 0.08 (s, 9 H, 3 Me), 1.83 (m, 2 H, CH2), 2.36 (s, 3 H,
CH3), 7.26 (d, 3J = 7.2 Hz, 2 H, 2 CH), 7.45 (t, 3J = 6.5 Hz, 2 H, 2
CH), 7.58–7.63 (m, 3 H, 3 CH), 8.03 (d, 3J = 7.0 Hz, 2 H, 2 CH),
10.69 (s, 1 H, NH). 13C NMR (125.7 MHz, CDCl3): δ = 0.62 (3 Me),
23.9 (CH3), 29.2 (CH2), 126.1 (2 CH), 127.4 (2 CH), 128.5 (2 CH),
129.8 (2 CH), 130.1 (CH), 134.5 (C), 140.1 (C), 142.7 (C), 157.3
(C), 168.1 (C). MS: m/z (%) = 388 (M+, 1), 268 (12), 171 (38), 120
(58), 105 (100), 77 (60). Anal. Calcd for C19H24N2O3SSi (388.56):
C, 58.73; H, 6.23; N, 7.21; Si, 7.23; S, 8.25. Found: C, 58.95; H,
6.51; N, 7.32; Si, 7.26; S, 8.34.
N-(N-Tosylpentanimidoyl)benzamide (4j)
Colorless solid; yield: 0.25 g (70%); mp 132–134 °C. IR (KBr):
3261, 1657, 1561, 1437, 1352, 1109 cm–1. 1H NMR (500.1 MHz,
CDCl3): δ = 0.79 (t, 3J = 7.1 Hz, 3 H, CH3), 1.45–1.67 (m, 4 H, 2
CH2), 2.29 (s, 3 H, CH3), 2.68 (t, 3J = 6.3 Hz, 2 H, CH2), 7.29 (d,
3J = 6.7 Hz, 2 H, 2 CH), 7.43 (d, 3J = 6.7 Hz, 2 H, 2 CH), 7.56–7.62
(m, 3 H, 3 CH), 8.05 (d, 3J = 6.9 Hz, 2 H, 2 CH), 10.67 (s, 1 H, NH).
13C NMR (125.7 MHz, CDCl3): δ = 5.9 (CH3), 20.5 (CH2), 24.5
(CH2), 24.8 (CH3), 27.2 (CH2), 126.4 (2 CH), 127.1 (2 CH), 129.5
(2 CH), 131.4 (2 CH), 133.8 (CH), 135.8 (C), 141.1 (C), 143.6 (C),
160.3 (C), 168.3 (C). MS: m/z (%) = 358 (M+, 1), 238 (16), 171
(39), 155 (68), 105 (100), 77 (79). Anal. Calcd for C19H22N2O3S
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–D