Direct Michael addition to electron-deficient alkenes using diorganyl dichalcogenides (Te/S) and NaBH4/PEG-400

Article abstract of DOI:10.1016/j.tetlet.2014.08.101

Nucleophilic species of tellurium and sulfur were generated in situ from the reaction of the respective diorganyl dichalcogenides with NaBH₄in PEG-400 as solvent and selectively added to electron-deficient alkenes. Chalcogenolate anions were directly added at mild conditions by this simple procedure and in all cases furnished the respective Michael adducts in short reaction times and good yields.

Full text of DOI:10.1016/j.tetlet.2014.08.101

Tetrahedron Letters 55 (2014) 5652–5655
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Tetrahedron Letters
journal homepage: www.elsevier.com/locate/tetlet
Direct Michael addition to electron-deficient alkenes using diorganyl
dichalcogenides (Te/S) and NaBH4/PEG-400
⇑
Gelson Perin , Elton L. Borges, Thiago J. Peglow, Eder J. Lenardão
LASOL, CCQFA, Universidade Federal de Pelotas—UFPel, PO Box 354, 96010-900 Pelotas, RS, Brazil
a r t i c l e i n f o
a b s t r a c t
Article history:
Nucleophilic species of tellurium and sulfur were generated in situ from the reaction of the respective
diorganyl dichalcogenides with NaBH4 in PEG-400 as solvent and selectively added to electron-deficient
alkenes. Chalcogenolate anions were directly added at mild conditions by this simple procedure and in all
cases furnished the respective Michael adducts in short reaction times and good yields.
Ó 2014 Elsevier Ltd. All rights reserved.
Received 13 June 2014
Revised 25 August 2014
Accepted 26 August 2014
Available online 1 September 2014
Keywords:
Organotellurium compounds
PEG-400
Organosulfur compounds
Michael adduct
a,b-Unsaturated carbonyl compounds
The addition of nucleophilic species of tellurium and sulfur to
efficient methods to prepare b-organyltellurocarbonyl compounds
is justifiable.
electron-deficient alkenes represents a very useful method for
the formation of new carbon–chalcogenium bond in organic syn-
thesis. Regarding organosulfur compounds, several methods were
described using readily available thiols in thia-Michael additions
to form C–S bonds.1 On the other hand, the formation of C–Te bond
via Te-Michael addition was scarcely studied, because the genera-
tion and use of the analog organyltellurol are not trivial. Both
adducts, b-organylthio- and b-organyltellurocarbonyl compounds,
are interesting intermediates in organic synthesis, for example, in
the synthesis of sulfones and sulfoxides,2 in the total synthesis of
geralcin A,3 and in the preparation of tetrazoles with antifungal
activity.4
Among the methods included for the formation of C–Te bonds
via telluro-Michael addition is the use of nucleophilic species gen-
erated in situ from C6H5TeSiMe3/SmI2,5 (ArTe)2/Sm/ZrCl4,6 BuLi/Te/
EtOH,7 (ArTe)2/Zn/ZrCl4,8 and Te/BuLi/H2O.9 However, most of
these methods present some drawbacks like the use of strong base,
addition of stoichiometric quantities of tBuOH or BuOH, acidic
extraction, and expensive reagents. In others cases, the preparation
of the nucleophilic species involves several steps, making them
time consuming and costly protocols. Besides scarce, these meth-
ods make intensive use of Volatile Organic Compounds (VOCs) as
solvent. In this sense, the development of practical, selective, and
Recently, we developed a new method for the in situ generation
of chalcogenolate anions by using the system (RY)2/NaBH4/PEG-
400 (Y = S, Se, Te). The nucleophilic species were successfully
added to alkynes to prepare selectively bis-chalcogen alkenes.10
More recently, we describe the direct Michael-type addition of
nucleophilic species of selenium generated in situ, using diorganyl
diselenide and NaBH4.11
However, to our knowledge, the direct hydrotelluration of
a,b-carbonyl compounds using diorganyl ditelluride and NaBH4
to afford Michael adducts was not yet described. In continuation
to our studies on the formation of carbon–chalcogenium bonds,
here we describe the addition of nucleophilic species of tellurium
and sulfur generated in situ using NaBH4/PEG-400 to electron-defi-
cient alkenes (Scheme 1).12,13
Initially, we chose as standard starting materials methyl acry-
late 1a and diphenyl ditelluride 2a to perform the optimization
studies under N2 atmosphere (Table 1). We studied the tempera-
ture, amounts of methyl acrylate, diphenyl ditelluride, reaction
time, and the nature of the solvent. When the nucleophilic tellu-
rium species was generated using 0.25 mmol of the ditelluride 2a
in PEG-400 (3.5 mL) in the presence of 0.5 mmol of acrylate 1a at
room temperature, the desired product 3a was obtained in 42%
yield after 1 h (Table 1, entry 1). To our surprise, by increasing
the temperature to 50 °C, a decrease in the yield of the desired
product 3a was observed (Table 1, entry 2). Next, experiments
were carried out varying the amount of 1a and 2a at room
⇑
Corresponding author. Tel./fax: +55 5332757533.
E-mail address: gelson_perin@ufpel.edu.br (G. Perin).
http://dx.doi.org/10.1016/j.tetlet.2014.08.101
0040-4039/Ó 2014 Elsevier Ltd. All rights reserved.

G. Perin et al. / Tetrahedron Letters 55 (2014) 5652–5655
5653
EWG
PEG-400, NaBH4
r.t. or 50 oC, N2
was used, methyl 3-(4-chlorophenytellanyl)propanoate 3c and
3-(4-chlorophenyltellanyl)propanenitrile 3g were obtained,
respectively, in 51% and 60% yields respectively (Table 2, entries
3 and 7). In contrast, the presence of electron-donors in the
aromatic ring of the ditelluride favors the reaction. Thus, when
4-methoxyphenylditelluride 2b and 4-methylphenylditelluride
2d were used, the desired products 3b, 3d, and 3h were obtained
in 80%, 69%, and 71% yields, respectively, (Table 2, entries 2, 4,
and 8). We observed that our new protocol is also suitable for dial-
kyl ditelluride 2e. Methyl 3-butyltelluropropanoate 3e and methyl
3-butyltelluro propanonitrile 3i were obtained in 80% and 95%
yields under our conditions (Table 2, entries 5 and 9). However,
when 1,2-disubstituted alkene was used, such as aryl acrylate, no
adduct was formed, with the starting material being recovered
even after 24 h of reaction.
We also tested the system NaBH4/PEG-400 using diorganyl
disulfide as chalcogenium source in the thia-Michael addition to
electron-deficient alkenes. To generate the nucleophilic species,
NaBH4 (0.6 mmol) was added to a mixture of diphenyl disulfide
2f or didodecyl disulfide 2g (0.6 mmol) in PEG-400 (3.5 mL) and
the mixture was stirred for 40 min at 50 °C under N2. Differently
to the ditelluride analog, in this case it was not possible to observe
a change in the color of the reaction mixture due the cleavage of
the S–S bond. Then, methyl acrylate 1a (0.5 mmol) was added
and the mixture was stirred for additional 2 h at 50 °C, affording
methyl 3-phenylthiopropanoate 3j in 87% yield (Table 2, entry
10). When a smaller amount of 2f (0.25 mmol) was used, 3j was
obtained only in 35% yield. The yield of 3j increased to 55% when
0.5 mmol of 2f was used. Thus the use of an excess of the nucleo-
philic species was necessary to prepare the sulfur analogs. The best
R
EWG
Y
R
Y
RY
2a g
-
1a d
-
3a-n
Scheme 1. General scheme of the reaction.
temperature (Table 1, entries 3–5). When an excess of ditelluride
2a was used (0.5 mmol) there was no increase in the yield of 3a
(Table 1, entry 3). However, in another experiment, it was observed
that by using 1.0 mmol of alkene 1a, the product 3a was obtained
in 75% yield (Table 1, entry 4). Similar result was obtained by fur-
ther increasing the amount of acrylate 1a to 1.5 mmol (Table 1,
entry 5).
Subsequently, we studied the influence of the reaction time and
it was observed that the yield of 3a decreased both, when 1a and
2a reacted for 0.5 h (Table 1, entry 6) and for 1.5 h (entry 7). When
the reaction mixture was stirred for a longer reaction time, its color
turned reddish and a large amount of diphenyl ditelluride was
recovered. Aiming to verify the influence of the solvent, the
reaction was performed also using ethanol, glycerol, and a mixture
ethanol/THF (Table 1, entries 8–10). The best result was obtained
using a 1:1 mixture of ethanol/THF (Table 1, entry 10); however,
the yields of 3a were inferior to that obtained using PEG-400
(entry 4).
In an optimized reaction, NaBH4 was added to a reddish mixture
of diphenyl ditelluride 2a and PEG-400. The heterogeneous reac-
tion mixture was stirred for 40 min at room temperature under
N2 atmosphere. After that, the color turned white, indicating the
cleavage of the Te–Te bond. Then, methyl acrylate 1a was added
and the mixture was stirred for additional 1.0 h, affording methyl
3-phenyltellanylpropanoate 3a in 75% yield. A plausible mecha-
nism for this reaction is similar to that proposed for the hydroch-
alcogenation of terminal alkynes using PEG-400, with the solvent
acting as a proton-donor in the reaction.14
Extending the scope of our methodology, the possibility of
performing the reaction with other ditellurides was investigated
and, in most cases, the reaction proceeded smoothly to give the
respective 3-organyltellurium esters 3a–e and nitrile 3f–i in good
yields (Table 2, entries 2–9). It was observed that the presence of
electron-withdrawing and electron-donating groups in the aryl
ditelluride affects the reactivity of the tellurium species (Table 2,
entries 2–4 and 7–8). Thus, when 4-chlorophenylditelluride 2c
reaction conditions were extended to other
a,b-unsaturated
alkenes and, except for acrylic acid 1c, in all the tested examples
the products were obtained in good yields (Table 2, entries
11–13). Besides, using dialkyl disulfide 2g, the product methyl
3-dodecylthiopropanoate 3n was obtained in 82% yield (Table 2,
entry 14).
Due to our interest in the synthetic applications of organochal-
cogen compounds, we performed the synthesis of the thiofunction-
alized hydrazide 4a,15 a member of a class of compounds that have
gained importance because of their biological and pharmacological
activities (Scheme 2).16 More recently, hydrazides containing the
group organo-sulfur or tellurium, were used for the synthesis of
vinyl-substituted 1,3,4-oxadiazoles,17 and of Cy-NTe, a reversible
Table 1
Optimization of the synthesis of methyl 3-phenyltellanylpropanoate 3aa
O
O
NaBH4, N2, solvent
temperature
Te
Te
Te
OMe
OMe
+
3a
1a
2a
Entry
1a (mmol)
2a (mmol)
Solvent
Time (h)
Yieldb (%)
1
2
3
4
5
6
7
8
9
0.5
0.5
0.5
1.0
1.5
1.0
1.0
1.0
1.0
1.0
0.25
0.25
0.5
0.25
0.25
0.25
0.25
0.25
0.25
0.25
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
PEG-400
Ethanol
1.0
1.0
1.0
1.0
1.0
0.5
1.5
1.0
1.0
1.0
42
30c
32d
75
76
60
50
45
Traces
65
Glycerol
Ethanol/THF
10
a
b
c
Reactions performed in the presence of 1a, 2a, NaBH4 (0.6 mmol), and solvent (3.5 mL) under N2 atmosphere at room temperature.
Yields are given for isolated product 3a.
Reaction performed at 50 °C.
1.2 mmol of NaBH4 was used.
d

5654
G. Perin et al. / Tetrahedron Letters 55 (2014) 5652–5655
Table 2
Addition of organyltellurolate and organylthiolate anions to electron-deficient alkenes
Entry
Alkenes 1
(RY)2
2
Product 3
Yielda (%)
75
O
O
Te
O
1
Te
2a
Te
O
1a
3a
OMe
Cl
MeO
Cl
O
Te
2
3
4
1a
1a
80
51
69
Te
2b
Te
O
3b
MeO
Cl
O
Te
Te
2c
Te
O
3c
O
Te
Te
1a
1a
Te
2d
Te
Te
Te
O
3d
O
5
6
80
73
2e
O
3e
CN
CN
2a
2c
1b
Te
3f
Cl
7
1b
60
CN
Te
3g
8
9
1b
1b
2d
2e
71
95
CN
CN
Te
3h
Te
3i
O
S
10
1a
87
S
S
O
S
3j
2f
CN
11
12
13
14
1b
2f
2f
2f
98
45
75
82
3k
3l
O
O
OH
S
OH
1c
S
O
1d
O
3m
10
O
S
S
10
1a
2g
S
O
10
3n
a
Yields are given for isolated products based on the formation of 0.5 mmol of 3.
additional 2.5 h at 50 °C, affording 3-phenylthiopropanehydrazide
4a in 86% yield (Scheme 2).
1. NaBH4/PEG-400
O
1a
2. methyl acrylate
3. NH2.NH2.H2O
S
NH2
In summary, by using the system (RTe)2 or (C6H5S)2/NaBH4/
PEG-400 to generate the nucleophilic species of chalcogenium, sev-
eral Te- and S-functionalized Michael adducts were easily and
selectively obtained. By this new protocol, a range of b-tellanyl
esters and nitrile and b-thio esters, nitrile, ketone, and acid were
directly prepared, without the need to use any additive. Methyl
3-phenylthiopropanoate 3j derived from methyl acrylate was
transformed into the respective hydrazide 4a in one pot, with
excellent yield.
S
S
N
H
4a
2f
Scheme 2. Synthesis of 3-phenylthiopropanehydrazide.
near-infrared fluorescent probe used to evaluate the ONOOÀ/GSH
redox status in cells and in vivo.18
Thus, after the synthesis of methyl 3-phenylsulfonylpropanoate
3j, hydrazine hydrate was added and the mixture stirred for

G. Perin et al. / Tetrahedron Letters 55 (2014) 5652–5655
5655
274.0211. 3-Phenyltellanylpropanenitrile 3f: Yield: 0.095 g (73%); Orangish oil;
1H NMR (CDCl3, 300 MHz): d 7.81–7.77 (m, 2H), 7.38–7.33 (m, 1H), 7.28–7.22
(m, 2H), 2.96–3.01 (m, 2H), 2.77–2.83 (m, 2H). 13C NMR (75 MHz, CDCl3); d
(ppm): 139.4, 129.5, 128.6, 119.9, 109.9, 20.5, À0.60. MS: m/z (rel. int.) 261
(44.7), 207 (53.0), 77 (100.0), 51 (48.4). HRMS (ESI): m/z calcld for C9H9NTe
[M]+: 260.9797; found: 260.9795. 3-(4-Chlorophenyltellanyl)propanenitrile 3g:
Acknowledgments
The authors are grateful to FAPERGS and CNPq (PRONEM 11/
2026-4), CAPES and FINEP for the financial support.
Yield: 0.089 g (60%); Orangish oil; 1H NMR (CDCl3, 400 MHz):
d 7.72 (d,
J = 8.4 Hz, 2H), 7.22 (d, J = 8.4 Hz, 2H), 2.98 (t, J = 7.4 Hz, 2H), 2.82 (t, J = 7.4 Hz,
2H). 13C NMR (100 MHz, CDCl3); d (ppm): 140.9, 135.3, 129.8, 119.7, 107.4,
20.5, À0.07. MS: m/z (rel. int.) 295 (35.1), 241 (82.4), 111 (53.5), 75 (100.0), 50
(38.6). HRMS (ESI): m/z calcld for C9H8ClNTe [M]+: 294.9407; found: 294.9402.
3-(4-Methylphenyltellanyl)propanenitrile 3h:6 Yield: 0.098 g (71%); Orangish oil;
1H NMR (CDCl3, 300 MHz): d 7.70–7.66 (m, 2H), 7.08–7.05 (m, 2H), 2.96–2.90
(m, 2H), 2.80–2.74 (m, 2H), 2.36 (s, 3H). 13C NMR (75 MHz, CDCl3); d (ppm):
139.8, 138.8, 130.4, 120.0, 105.8, 21.2, 20.4, À0.73. MS: m/z (rel. int.) 275
(36.8), 221 (54.8), 91 (100.0). 3-Butyltellanylpropanenitrile 3i:9 Yield: 0.114 g
(95%). Yellowish oil; 1H NMR (CDCl3, 400 MHz): d 2.92–2.88 (m, 2H), 2.81–2.77
(m, 4H), 1.76 (quint, J = 7.6 Hz, 2H), 1.40 (sext, J = 7.6 Hz, 2H), 0.93 (t, J = 7.3 Hz,
3H). 13C NMR (100 MHz, CDCl3); d (ppm): 119.9, 34.0, 24.9, 21.4, 13.3, 4.2,
À7.0. MS: m/z (rel. int.) 241 (31.5), 185 (24.0), 157 (22.3), 57 (100.0), 54 (43.6),
41 (97.1).
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2014.08.
101.
References and notes
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2109; (b) Chu, C.-M.; Gao, S.; Sastry, M. N. V.; Yao, C.-F. Tetrahedron Lett. 2005,
46, 4971; (c) Chu, C.-M.; Huang, W.-J.; Lu, C.; Wu, P.; Liu, J.-T.; Yao, C.-F.
Tetrahedron Lett. 2006, 47, 7375; (d) Chu, C.-M.; Gao, S.; Sastry, M. N. V.; Kuo,
C.-W.; Lu, C.; Liu, J.-T.; Yao, C.-F. Tetrahedron 2007, 63, 1863; (e) Khatik, G. L.;
Sharma, G.; Kumar, R.; Chakraborti, A. K. Tetrahedron 2007, 63, 1200; (f) Azizi,
N.; Khajeh-Amiri, A.; Ghafuri, H.; Bolourtchian, M. Green Chem. Lett. Rev. 2009,
2, 43; (g) Sharma, G.; Kumar, R.; Chakraborti, A. K. Tetrahedron Lett. 2008, 49,
4272; (h) Lenardão, E. J.; Ferreira, P. C.; Jacob, R. G.; Perin, G.; Leite, F. P. L.
Tetrahedron Lett. 2007, 48, 6763; (i) Lenardão, E. J.; Trecha, D. O.; Ferreira, P. C.;
Jacob, R. G.; Perin, G. J. Braz. Chem. Soc. 2009, 20, 93; (j) Gaggero, N.; Albanese,
D. C. M.; Celentano, G.; Banfi, S.; Aresi, A. Tetrahedron: Asymmetry 2011, 22,
1231; (k) Peng, A.; Rosenblatt, R.; Nolin, K. Tetrahedron Lett. 2012, 53, 2712.
2. (a) Hussain, S.; Bharadwaj, S. K.; Pandey, R.; Chaudhuri, M. K. Eur. J. Org. Chem.
2009, 3319; (b) Reddy, C. V.; Verkade, J. G. J. Mol. Catal. A: Chem. 2007, 272, 233.
3. Goff, G. L.; Roulland, E.; Ouazzani, J. Tetrahedron Lett. 2013, 54, 5299.
4. Líbero, F. M.; Xavier, M. C. D.; Victoria, F. N.; Nascente, P. S.; Savegnago, L.;
Perin, G.; Alves, D. Tetrahedron Lett. 2012, 53, 3091.
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6. Zhang, S.; Zhang, Y. Synth. Commum. 2000, 30, 285.
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9. Comasseto, J. V.; Gariani, R. A.; Princival, J. L.; Santos, A. A.; Zinn, F. K. J.
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10. Perin, G.; Borges, E. L.; Alves, D. Tetrahedron Lett. 2012, 53, 2066.
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12. General procedure for the direct synthesis of b-organyltellanylcarbonyl compounds
3a–i: To a mixture of diorganyl ditelluride 2a–e (0.25 mmol) in PEG-400
(3.5 mL) under N2 atmosphere, NaBH4 (0.023 g, 0.6 mmol) was added at room
temperature and the mixture was stirred for 40 min. Then, the appropriate
13. General procedure for the direct synthesis of b-organylthiocarbonyl compounds 3j–
n: To a mixture of diorganyl disulfide 2f–g (0.6 mmol) in PEG-400 (3.5 mL)
under N2 atmosphere, NaBH4 (0.023 g, 0.6 mmol) was added at room
temperature and the mixture was stirred at 50 °C for 40 min. Then, the
appropriate alkene 1 (0.5 mmol) was added and the mixture was stirred at
50 °C for additional 2 h. After, the solution was cooled to room temperature,
diluted with ethyl acetate (10.0 mL), and washed with water (3x 10.0 mL). The
organic phase was separated, dried over MgSO4, and the solvent was
evaporated under reduced pressure. The product was isolated by column
chromatography using hexanes or hexanes/ethyl acetate as eluent. All the
compounds were characterized and the spectral data are listed below: Methyl
3-phenylthiopropanoate 3j: Yield: 0.085 g (87%); Colorless oil; 1H NMR (CDCl3,
400 MHz): d 7.37–7.34 (m, 2H), 7.30–7.25 (m, 3H), 7.21–7.17 (m, 1H), 3.66 (s,
3H), 3.16 (t, J = 7.3 Hz, 2H), 2.62 (t, J = 7.5 Hz, 2H). 13C NMR (100 MHz, CDCl3); d
(ppm): 172.0, 135.1, 130.0, 128.9, 126.5, 51.7, 34.1, 29.0. MS: m/z (rel. int.) 196
(100.0), 136 (58.5), 123 (62.3), 109 (36.3), 87 (19.4), 77 (13.8). HRMS (ESI): m/z
calcd
for
C10H12O2S
[M+H]+:
197.0636;
found:
197.0633.
3-
Phenylthiopropanenitrile 3k:19,1i Yield: 0.080 g (98%); Colorless oil; 1H NMR
(CDCl3, 400 MHz): d 7.42–7.39 (m, 2H), 7.35–7.25 (m, 3H), 3.10 (t, J = 7.2 Hz,
2H), 2.57 (t, J = 7.3 Hz, 2H) 13C NMR (100 MHz, CDCl3); d (ppm): 133.1, 131.3,
129.3, 127.6, 117.8, 30.1, 18.1. MS: m/z (rel. int.) 163 (65.2), 123 (100.0), 109
(15.0), 77.0 (14.3). 3-Phenylthiopropanoic acid 3l:20 Yield: 0.041 g (45%); White
solid; 1H NMR (CDCl3, 400 MHz): d 10.5 (br s, 1H), 7.38–7.36 (m, 2H), 7.31–7.27
(m, 2H), 7.24–7.19 (m, 1H), 3.15 (t, J = 7.3 Hz, 2H), 2.67 (t, J = 7.4 Hz, 2H). 13C
NMR (100 MHz, CDCl3); d (ppm): 178.0, 134.9, 130.3, 129.0, 126.7, 34.2, 28.8.
MS: m/z (rel. int.) 182 (100.0), 123 (92.5), 109 (33.7), 77 (16.4). 3-Phenylthio-
cyclohexanone 3m:21 Yield: 0.077 g (75%). Colorless oil. 1H NMR (CDCl3,
400 MHz): d 7.42–7.40 (m, 2H), 7.32–7.24 (m, 3H), 3.46–3.39 (m, 1H), 2.69–
2.64 (m, 1H), 2.39–2.24 (m, 3H), 2.15–2.09 (m, 2H), 1.77–1.66 (m, 2H). 13C
NMR (100 MHz, CDCl3); d (ppm): 208.4, 133.0, 132.9, 128.9, 127.5, 47.5, 45.9,
40.6, 31.0, 23.8. MS: m/z (rel. int.) 208 (M++2; 38.5), 110 (100.0), 81 (39.3).
Methyl 3-dodecylthiopropanoate 3n:22 Yield: 0.118 g (82%). Colorless oil. 1H
NMR (CDCl3, 400 MHz): d 3.69 (s, 3H), 2.77 (t, J = 7.5 Hz, 2H), 2.60 (t, J = 7.5 Hz,
2H), 2.52 (t, J = 7.5 Hz, 2H), 1.58 (quint, J = 7.3 Hz, 2H), 1.39–1.25 (m, 18H), 0.88
(t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3); d (ppm): 172.3, 51.6, 34.8, 32.3,
31.9, 29.6 (2C), 29.59, 29.56, 29.5, 29.3, 29.2, 28.9, 27.1, 22.6, 14.0. MS: m/z (rel.
int.) 288 (21.0), 201 (100.0), 87 (25.3).
alkene
1 (1.0 mmol) was added and the mixture was stirred at room
temperature for additional 1 h. After, the mixture was diluted with ethyl
acetate (10.0 mL) and washed with water (3 Â 10.0 mL). The organic phase was
separated, dried over MgSO4, and the solvent was evaporated under reduced
pressure. The product was isolated by preparative TLC on silica gel using
hexane or hexane/ethyl acetate as eluent. All the compounds were
characterized and the spectral data are listed below: Methyl 3-
phenyltellanylpropanoate 3a: Yield: 0.110 g (75%); Orangish oil; 1H NMR
(CDCl3, 300 MHz): d 7.77–7.73 (m, 2H), 7.33–7.18 (m, 3H), 3.66 (s, 3H), 3.05–
3.00 (m, 2H), 2.94–2.89 (m, 2H). 13C NMR (100 MHz, CDCl3); d (ppm): 173.6,
138.8, 129.2, 127.9, 111.5, 51.8, 36.6, 0.44. MS: m/z (rel. int.) 294 (30.6), 207
(26.3), 87 (100.0), 77 (85.8). HRMS (ESI): m/z calcd for C10H12O2Te [M+H]+:
294.9978; found: 294.9972. Methyl 3-(4-methoxyphenyltellanyl)propanoate 3b:
Yield: 0.130 g (80%); Orangish oil; 1H NMR (CDCl3, 400 MHz): d 7.72–7.68 (m,
2H), 6.78–6.75 (m, 2H), 3.79 (s, 3H), 3.66 (s, 3H), 2.96–2.92 (m, 2H), 2.87–2.83
(m, 2H). 13C NMR (100 MHz, CDCl3); d (ppm): 173.5, 160.0, 141.4, 115.3, 100.4,
55.1, 51.7, 36.6, 0.54. MS: m/z (rel. int.) 324 (85.3), 237 (99.5), 108 (86.0), 87.0
14. Lenardão, E. J.; Silva, M. S.; Sachini, M.; Lara, R. G.; Jacob, R. G.; Perin, G.
ARKIVOC 2009, xi, 221.
15. General procedure for the one pot synthesis of 3-phenylthiopropanehydrazide 4a:
After preparation of 3j (0.5 mmol) according to the method described above,
hydrazine hydrate (0.6 mL) was added and the mixture was stirred for
additional 2.5 h at 50 °C. Then, the solution was cooled to room temperature,
diluted with ethyl acetate (10.0 mL), and washed with water (3 Â 10.0 mL).
The organic phase was separated, dried over MgSO4, and the solvent was
evaporated under reduced pressure. The product was purified by re-
crystallization from hexanes. The compound was fully characterized and the
spectral data are listed below: 3-phenylthiopropanehydrazide 4a: Yield: 0.084 g
(86%). 1H NMR (DMSO-d6, 300 MHz): d 9.04 (br s, 1H), 7.35–7.14 (m, 5H), 4.19
(br s, 2H), 3.14 (t, J = 7.3 Hz, 2H), 2.35 (t, J = 7.3 Hz, 2H). 13C NMR (75 MHz,
DMSO-d6); d (ppm): 169.8, 136.1, 129.3, 128.3, 125.9, 33.4, 28.3. MS: m/z (rel.
int.) 196 (47.9), 123 (100.0), 109 (57.1), 87 (20.0).
16. Kumar, L. V.; Naik, P. J.; Khan, P. S.; Reddy, A. B.; Sekhar, T. C.; Der Swamy, G. N.
Pharm. Chem. 2011, 3, 317.
17. Pardeshi, S. P.; Patil, S. S.; Patil, A. A.; Bobade, V. D. Res. Chem. Intermed. 2013,
39, 3399.
18. Yu, F.; Li, P.; Wang, B.; Han, K. J. Am. Chem. Soc. 2013, 135, 7674.
19. Adams, H.; Anderson, J. C.; Bell, R.; Jones, D. N.; Peel, M. R.; Tomkinson, N. C. O.
J. Chem. Soc., Perkin Trans. 1 1998, 3967.
20. Gao, S.; Tseng, C.; Tsai, C. H.; Yao, C.-F. Tetrahedron 2008, 64, 1955.
21. Yang, Y.; Rioux, R. M. Green Chem. 2014, 16, 3916.
(100.0). HRMS (ESI): m/z calcd for
C
11H14O3Te [M]+: 324.0005; found:
324.0000. Methyl 3-(4-chlorophenyltellanyl)propanoate 3c: Yield: 0.084 g
(51%); Orangish oil; 1H NMR (CDCl3, 400 MHz): d 7.68–7.65 (m, 2H), 7.19–
7.16 (m, 2H), 3.67 (s, 3H), 3.03–2.99 (m, 2H), 2.92–2.88 (m, 2H). 13C NMR
(100 MHz, CDCl3); d (ppm): 173.4, 140.3, 134.5, 129.5, 109.1, 51.8, 36.5, 0.94.
MS: m/z (rel. int.) 328 (27.4), 241 (25.4), 111.0 (20.3), 87.0 (100.0). HRMS (ESI):
m/z calcd for C10H11ClO2Te [M+H]+: 328.9588; found: 328.9583. Methyl 3-(4-
Methylphenyltellanyl)propanoate 3d:6 Yield: 0.106 g (69%); Orangish oil; 1H
NMR (CDCl3, 300 MHz): d 7.64 (d, J = 8.0 Hz, 2H), 7.03 (d, J = 8.0 Hz, 2H), 3.66 (s,
3H), 3.00–2.95 (m, 2H), 2.91–2.85 (m, 2H), 2.34 (s, 3H). 13C NMR (75 MHz,
CDCl3); d (ppm): 173.6, 139.2, 137.9, 130.1, 107.2, 51.7, 36.6, 21.2, 0.35. MS: m/
z (rel. int.) 308 (44.6), 221 (32.8), 91 (100.0), 87 (79.7). Methyl 3-butyltellanyl-
propanoate 3e: Yield: 0.110 g (80%); Orangish oil; 1H NMR (CDCl3, 400 MHz): d
3.69 (s, 3H), 2.90–2.86 (m, 2H), 2.81–2.77 (m, 2H), 2.68 (t, J = 7.5 Hz, 2H), 1.73
(quint, J = 7.4 Hz, 2H), 1.39 (sext, J = 7.4 Hz, 2H), 0.92 (t, J = 7.3 Hz, 3H). 13C
NMR (100 MHz, CDCl3); d (ppm): 173.5, 51.6, 37.2, 34.2, 25.0, 13.2, 3.3, À6.0.
MS: m/z (rel. int.) 274 (32.6), 215 (27.4), 186 (33.9), 158 (27.8), 87 (28.0), 57
(100.0). HRMS (ESI): m/z calcld for C8H16O2Te [M]+: 274.0213; found:
22. Chaudhuri, M. K.; Hussain, S. J. Mol. Catal A: Chem. 2007, 269, 214.