4
Tetrahedron
G.; Dada, R. Tetrahedron Lett. 2016, 57, 591; (g) Yaragorla, S.;
Dada, R.; Pareek, A. Singh, G. RSC Adv. 2016, 6, 28865.
Rokade, B. V.; Prabhu, K. R. J. Org. Chem. 2012, 77, 5364.
In summary, we have developed a facile method for the
sequential one-pot Schmidt-Ritter reaction from the easily
available aldehydes, sodium azide and alcohols with TfOH. For
the first time we developed a new method for the synthesis of N-
acylimides through Schmidt reaction and proved that this imides
are also the intermediates in the Ritter reaction to form the
amides. This method ensures the wide substrate scope with
excellent yields and the products were isolated by simple
filtration.
15.
16.
17.
Refer to supporting information for optimization table.
(a) Habibi, Z.; Salehi, P.; Zolfigol, M.A.; Yousefi, M. Synlett. 2007,
5, 812; (b) Ogawa, T.; Miyazaki, K.; Suzuki, H. Chem. Lett. 1990, 19,
1651; (c) Davidson, D.; Skovronek, H. J. Am. Chem. Soc. 1958, 80,
376; (d) Zilberman, E. N. Russ. Chem. Rev. 1960, 29, 331; (e)
Durrell, W. S.; Young, J. A.; Dresdner, R. D. J. Org. Chem. 1963, 28,
831; (f) Bowser, J. R.; Williams, P. J.; Kurz, K. J. Org. Chem. 1983,
48, 4111; (g) Wheeler, O. H.; Rosado, O. In The Chemistry of
Amides; Zabicky, J., Ed.; J. Wiley and Sons: New York, 1970, 335;
(h) Challis, B. C.; Challis, J. The Chemistry of Amides; Zabicky, J.,
Ed.; J. Wiley and Sons: New York, 1970, 759.
Acknowledgements
GS and RD thank Central University of Rajasthan for the fellowship and SY
thank Council of Scientific and Industrial Research (CSIR)-India for the
financial support under Extramural Research Grant -No. 02(0200)/14/EMR-II
18.
19.
For copies of 1H NMR and 13C NMR, see the supporting information.
Jiang, H. Org. Lett. 2011, 13, 1028; (d) Shi, F. Tetrahedron Lett.
2010, 51, 6049; (e) Kalkhambkar, R. G. Tetrahedron Lett. 2011, 52,
867; (f) Barbero, M. Eur.Org. Chem. 2009, 3, 430; (g) Bellamy, E.;
Chem. Lett. 2012, 23, 293; (i) Bai, C.; Yao, X.; Li, Y. ACS
Catalysis 2015, 5, 884; (j) Huang, P.-Q.; Geng, H. Org. Chem. Front.
2015, 2, 150.
General experimental procedure for the synthesis Amides 4: To a
magnetically stirred solution of benzaldehyde (1 mmol) and NaN3
(1.5 mmol) in AcOH (0.2 mL), TfOH (2 mmol) was added and the
reaction mixture was heated at 40 oC for 1-2 h. On the complete
conversion of aldehyde (monitored by TLC), alcohol (1 mmol) was
added along with TfOH (1 mmol). The reaction was continued to
heating at 90 oC (in the case of t-butanol the reaction temperature was
40 oC) for another 3-5 h. After the completion, the reaction was
cooled to 0 oC and saturated aq. NaHCO3 was added slowly. The
precipitate formed was filtered and washed with plenty of cold water
and dried to obtain the desired secondary benzamide as white solid in
98% yield. (Compounds obtained were pure hence, no further
References
1.
2.
3.
4.
Boonen, J.; Bronselaer, A.; Nielandt, J.; Veryser, L.; De Tré, G.; De,
B. S. J. Ethnopharmacol. 2012, 142, 563.
Stryer, L. In Biochemistry, 4th ed.; W.H. Freeman: New York, 1995,
17.
(a) Forsyth, C. J. Nat. Chem. 2010, 2, 252; (b) Um S., Pyee, Y. ; Kim
E.-H.; Lee, S. K.; Shin, J.; Oh, D.-C. Mar. Drugs 2013, 11, 611.
Ghose, A. K.; Viswanadhan, V. N.; Wendoloski, J. J. J. Comb.
Chem. 1999, 1, 55.
20.
5.
6.
Termistoteles, D. D. J. Appl. 1983, 509, 442.
(a) Humphrey, J. M.; Chamberlin, A. R. Chem. Rev. 1997, 97, 2243;
(b) Bode, J. W. Curr. Opin. Drug Discov. Dev. 2006, 9, 765; (c)
Cupido, T. ; Tulla-Puche, J.; Spengler, J.; Albericio, F. Curr.
Opin.Drug Discov. Dev. 2007, 10, 768.
7.
8.
Wieland, T. ; Bodanszky, M. Springer, 1991.
Constable, D. J. C. ; Dunn, P. J.; Hayler, J. D.; Humphrey, G. R.;
Leazer Jr. J. L.; Linderman, R. J.; Lorenz, K.; Manley, J.; Pearlman,
B. A.; Wells, A.; Zaks, A.; Zhang, T. Y. Green Chem. 2007, 9, 411.
(a) Marcelli, T. Angew. Chem. Int. Edn. 2010, 49, 6840; (b) Ishihara,
K. Tetrahedron 2009, 65, 1085; (c) Ishihara, K.; Ohara, S.;
Yamamoto, H. J. Org. Chem. 1996, 61, 4196; (d) Tang, P. Org.
Synth. 2005, 81, 262; (e) Al-Zoubi, R. M.; Marion, O.; Hall, D. G.
Angew. Chem. Int. Edn, 2008, 47, 2876; (f) Charville, H.; Jackson,
D.; Hodges, G.; Whiting, A. Chem. Commun. 2010, 46, 1813; (g)
Lanigan, R.M.; Starkov, P.; Sheppard, T. D. J .Org. Chem. 2013, 78,
4512. For reviews on amide bond formation, see: (h) Pattabiraman, B.
R.; Bode, J. W. Nature 2011, 480, 471; (i) Montalbetti, C. A. G. N.;
Falque, V. Tetrahedron 2005, 61, 10827; (j) Valeur, E.; Bradley, M.
Chem. Soc. Rev. 2009, 38, 606; (k) Kim, J.-G.; Jang, D. O. Bull.
Korean Chem. Soc. 2009, 30, 1435.
(a) Ritter, J. J.; Minieri, P. P. J. Am. Chem. Soc. 1948, 70, 4045; (b)
Densonand, F. R.; Ritter, J. J. J. Am. Chem. Soc. 1949, 71, 4128; (c)
Krimen, L. I.; Cota, D. J. Org. React. 1969, 17, 213; (d) Guérinot,
A.; Reymond, S.; Cossy, J. Eur. J. Org. Chem. 2012, 19; (e) Jiang,
D.; He, T.; Ma, L.; Wang, Z. RSC Adv. 2014, 4, 64936; (e) Karimian,
E.; Akhlaghinia, B.; Ghodsinia, S. S. E. J. Chem. Sci. 2016, 128,
429.
9.
purification
or
recrystallisation
was
required).
N-(tert-
butyl)benzamide (4a).10a,19 White solid; MP: 132-134 C; Yield: 96%;
IR (KBr): 3334, 2980, 2933, 1634 cm-1; 1H NMR (500 MHz, CDCl3):
δ 7.75-7.74 (d, J = 7 Hz, 2H), 7.51-7.48 (m, 1H); 7.45-7.42 (m, 2H),
5.98 (s, 1H), 105 (s, 9H); 13C NMR (125 MHz, CDCl3): δ 166.9,
135.9, 131.1, 128.4, 126.7, 51.6, 28.8 ppm; HRMS: calcd. for
[M+H]+ C11H15NO: 177.1153, found: 177.1155. General procedure
o
for the syntheses of N-(tert-butyl)amides (6).
To a
magnetically stirred solution of aldehyde (1 mmol) and NaN3 (1.5
mmol) in AcOH (0.2 mL), TfOH (1 mmol) was added and the
reaction mixture was heated at 40 oC for 1-2 hrs. On the complete
conversion of aldehyde (monitored by TLC) tert-butyl acetate was
added alongwith TfOH (1 mmol).The reaction was continued to
heating at 40 oC for another 3-5 hrs. After the completion, the
reaction was brought to room temperature and ice-cooled aq. sat.
NaHCO3 was added to the reaction mixture. The precipitate formed
was filtered and washed with plenty of cold water and dried to obtain
the desired benzamide as white solid in 96% yield. (Compounds
obtained were pure hence, no further purification or recrystallisation
was required). Methyl 4-(tert-butylcarbamoyl)benzoate (6a).10a,19
10.
11.
12.
(a) Yadav, J. S.; Reddy, B. V. S.; Kumar, G. G. K. S. N.; Reddy, G.
M. Tetrahedron Lett. 2007, 48, 7155; (b) Yadav, J. S.; Reddy, B. V.
S.; Kumar, G. G. K. S. N.; Reddy, G. M. Tetrahedron Lett. 2007, 48,
4903.
(a) Epstein, O. L.; Rovis, T. J. Am. Chem. Soc. 2006, 128, 16480; (b)
Sabhitha, G.; Bhikshapathi, M.; Nayak, S.; Yadav, J. S.; Ravi, R.
Tetrahedron Lett. 2008, 49, 5727.
o
Yellow solid; MP: 128-130 C; Yield: 93%; IR (KBr): ν 3415, 3051,
2952, 1638, 1564 cm-1; 1H NMR (500 MHz, CDCl3): δ 8.1 (d, J = 8.5
Hz, 2H), 7.79 (d, J = 8.5 Hz, 2H), 6.01 (s, 1H), 3.96 (s, 3H), 1.48 (s,
9H); 13C NMR (125 MHz, CDCl3): δ 166.3, 166.0, 139.8, 132.5,
129.8, 126.8, 52.4, 51.9, 28.8 ppm; HRMS: calcd. for [M+H]+
C13H17NO3: 235.1208 , found: 235.1210. General procedure for the
syntheses of N-acylimides (5): To a magnetically stirred solution of
benzaldehyde (1 mmol), NaN3 (1.5 mmol) and AcOH (0.2 mL),
TfOH (1 mmol) was added and the reaction mixture was heated at 40
oC for 8-10 hrs. On completion (monitored by TLC) reaction was
brought to 0 oC and sat. solution of NaHCO3 was added to the
resultant reaction mixture and the precipitate formed was filtered and
dried to obtain desired N-acetylbenzamide in 95% yield. N-
acetylbenzamide (5).17a White solid; MP: 110-112 oC; Yield: 95%; IR
13.
14.
(a) Hazarika, N.; Baishya, G. Eur. J. Org. Chem. 2014, 5686; (b)
Hazarika, N.; Baishya, G.; Phukan, P. Synthesis 2015, 47, 2851.
(a) Yaragorla, S.; Singh, G.; Saini, P. L.; Reddy, M. K. Tetrahedron
Lett. 2014, 55, 4657; (b) Yaragorla, S.; Pareek, A.; Dada, R.
Tetrahedron Lett. 2015, 56, 4770; (c) Yaragorla, S.; Saini, P. L.;
Singh, G. Tetrahedron Lett. 2015, 56, 1649; (d) Yaragorla, S.; Singh,
G.; Dada, R. Tetrahedron Lett. 2015, 56, 5924; (e) Yaragorla, S.;
Dada, R.; Singh, G. Synlett. 2016, 27, 912; (f) Yaragorla, S.; Singh,