10.1002/ejoc.201900563
European Journal of Organic Chemistry
COMMUNICATION
[10] a) M. Lim, W. Y. Ren, R. S. Klein, J. Org. Chem. 1982, 47, 4594; b) H.
Suzuki, H. Tani, S. Takeuchi, Bull. Chem. Soc. Jpn. 1985, 58, 2421, c)
D. S. Bose, B. Jayalakshmi, P. R. Goud, Synthesis 1999, 1724.
[11] M. Avalos, R. Babiano, P. Cintas, C. J. Durán, F. J. Higes, J. L. Jiménez,
I. López, J. C. Palacios, Tetrahedron 1997, 53, 14463.
It is worth mentioning that the Ph3BiCl2-mediated process is
selective as the reaction stopped at the dehydrosulfurization
stage with no further reaction towards dimeric thiadiazoles. The
latter could have been generated in situ by condensation of the
produced nitriles with the starting thioamides, as previously
observed by others.[19]
[12] For example, use of in situ generated formamide chloride as reagent: J.
Liebscher, Synthesis 1982, 1084.
[13] a) For example, use of EDCI as reagent: D. S. Bose, K. S. Sunder, Synth.
Commun. 1999, 29, 4235; b) pyBOP as reagent: D. S. Bose, A.
V. Narsaiah, Synthesis 2001, 373.
Conclusion
We have shown that the dehydrosufurization of thioamides into
the corresponding nitriles can be easily performed using
triphenylbismuth dichloride which acted as a mild, efficient,
selective, and convenient reagent. The procedure described
herein permitted not only access to nitriles but also to cyanamides
and thiocyanates starting from the corresponding thioureas and
dithiocarbamates, respectively. The salient features of the
reported procedure are the smoothness of the operating
conditions (room temperature, no inert atmosphere), the
selectivity of the transformation (no side products), and its fast
kinetics (ca. 15 min). As a reminder, bismuth is the least toxic of
heavy metals.[20]
[14] a) T. Arnauld, D. H. R. Barton, E. Doris, Tetrahedron Lett. 1997, 38, 365;
b) T. Arnauld, D. H. R. Barton, E. Doris, Tetrahedron 1997, 53, 4137; c)
T. Arnauld, D. H. R. Barton, J. F. Normant, E. Doris, J. Org. Chem. 1999,
64, 6915; d) C. Ménard, E. Doris, C. Mioskowski, Tetrahedron Lett. 2003,
44, 6591; e) D. V. Nguyen, P. Prakash, E. Gravel, E. Doris. RSC Adv.
2016, 6, 89238.
[15] a) J. Alliot, E. Gravel, E. Doris, Synthesis 2013, 45, 2861; b) D. Clarisse,
P. Prakash, V. Geertsen, F. Miserque, E. Gravel, E. Doris, Green Chem.
2017, 19, 3112; c) P. Prakash, R. A. Kumar, F. Miserque, V. Geertsen,
E. Gravel, E. Doris. Chem. Commun. 2018, 54, 3644.
[16] For reviews on the use of organobismuth reagents, see: a) J. P. Finet,
Chem. Rev. 1989, 89, 1487; b) Organobismuth Chemistry, H. Suzuki and
Y. Matano Eds, Elsevier Science, 2001; c) Y. Matano, Top. Curr. Chem.
2012, 311, 19; d) S. Shimada, M. L. N. Rao, Top. Curr. Chem. 2012, 311,
199; e) A. Gagnon, J. Dansereau, A. Le Roch, Synthesis 2017, 49, 1707;
f) A. Gagnon, E. Benoit, A. Le Roch, Science of Synthesis Updates 2018,
4, 1.
Experimental Section
[17] D. H. R. Barton, N. Yadav-Bhatnagar, J. C. Blazejewski, B. Charpiot, J.
P. Finet, D. J. Lester, W. B. Motherwell, M. T. Barros Papoula, S. P.
Stanforth, J. Chem. Soc., Perkin Trans. 1 1985, 2657.
General dehydrosulfurization procedure. The transformation of
benzothioamide 1f is given as a typical example: To a solution of thioamide
1f (13.7 mg, 0.1 mmol, 1 equiv.) in CH2Cl2 (1 mL) was added Ph3BiCl2 (61
mg, 1.2 equiv.) and triethylamine (42 µL, 3 equiv.). The reaction was stirred
at room temperature for 15 min and the crude product was directly purified
by preparative thin layer chromatography over silica gel with elution with
hexane/AcOEt 98:2 to afford 2f in 89% yield.
[18] Y. Murata, N. Matsumoto, M. Miyata, Y. Kitamura, N. Kakusawa, M.
Matsumura, S. Yasuike, J. Organomet. Chem. 2018, 859, 18.
[19] a) T. Fukumoto, T. Matsuki, N. X. Hu, Y. Aso, T. Otsubo, F. Ogura, Chem.
Lett. 1990, 19, 2269; b) K. Yajima, K. Yamaguchia, N. Mizuno, Chem.
Commun. 2014, 50, 6748.
[20] R. Mohan, Nat. Chem. 2010, 2, 336.
Acknowledgements
Elumalai Gopi thanks the Enhanced Eurotalents program for
support. Mrs Sabrina Lebrequier is gratefully acknowledged for
technical assistance. The “Service de Chimie Bioorganique et de
Marquage” belongs to the Laboratory of Excellence in Research
on Medication and Innovative Therapeutics (ANR-10-LABX-0033-
LERMIT).
Keywords: thioamides • nitriles • dehydrosulfurization • bismuth
[1]
[2]
R. C. Larock, Comprehensive Organic Transformations, VCH, New-York,
1989.
a) D. T. Mowry, Chem. Rev. 1948, 42, 189; b) G. P. Ellis, T. M. Romney-
Alexander, Chem. Rev. 1987, 87 , 779; c) G. Yan, Y. Zhang, J. Wang,
Adv. Synth. Catal. 2017, 359, 4068.
[3]
[4]
A. M. Nauth, T. Opatz, Org. Biomol. Chem. 2019, 17, 11.
a) S. Enthaler, S. Inoue, Chem. Asian J. 2012, 7, 169 ; b) S. Enthaler,
Eur. J. Org. Chem. 2011, 4760.
[5]
[6]
[7]
[8]
M. K. Singh, M. K. Lakshman, J. Org. Chem. 2009, 74, 3079.
Y. Preger, T. W. Root, S. S. Stahl, ACS Omega 2018, 3, 6091.
V. N. Telvekar, R. A. Rane, Tetrahedron Lett. 2007, 48, 6051.
T. Mineno, Y. Takebe, C. Tanaka, S. Mashimo, Int. J. Org. Chem. 2014,
4, 169.
[9]
K. Yamaguchi, K. Yajima, N. Mizuno, Chem. Commun. 2012, 48, 11247.
This article is protected by copyright. All rights reserved.