Amidation of norbornene with organic nitriles in the presence of water catalyzed by iron compounds

Article abstract of DOI:10.1016/j.tetlet.2015.09.131

The amidation of norbornene with various nitriles was performed in the presence of water under the action of FeCl₃·6H₂O to give N-(exo-2-norbornyl)acylamides in 76-95% yield.

Full text of DOI:10.1016/j.tetlet.2015.09.131

Tetrahedron Letters 56 (2015) 6368–6369
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Amidation of norbornene with organic nitriles in the presence of
water catalyzed by iron compounds
⇑
Ravil I. Khusnutdinov , Tatyana M. Oshnyakova
Institute of Petrochemistry and Catalysis, Russian Academy of Sciences, 141 Prospekt Oktyabrya, Ufa 450075, Russian Federation
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 April 2015
Revised 6 July 2015
Accepted 26 September 2015
Available online 30 September 2015
The amidation of norbornene with various nitriles was performed in the presence of water under the
action of FeCl3Á6H2O to give N-(exo-2-norbornyl)acylamides in 76–95% yield.
Ó 2015 Elsevier Ltd. All rights reserved.
Keywords:
Amidation
Norbornene
Organic nitriles
Water
Iron-containing catalysts
The reaction of nitriles with olefins using the Ritter reaction is
widely used to synthesize N-substituted amides.1–5 For example
the amidation of olefins with acetonitrile has been reported to be
catalyzed by mineral acids such as H2SO4, PhSO3H, HF, and oleum
as well as heteropoly acids.2–5 Specifically, the reaction of nor-
bornene 1 with acetonitrile in the presence of a large excess of
H2SO4 has previously been reported for the formation of
N-(exo-2-norbornyl)acetamide 2 in 70% yield.5
1). Compound 2 could be separated from the mixture of products
in 76% isolated yield.6
Increasing the temperature to 140 °C did not result in an
increase in yield but promoted the norbornene isomerization side
reaction affording tricyclo[2.2.1.02,6]heptane 4 (Table 1, entry 2).
When FeCl3Á6H2O was replaced by anhydrous FeCl3, the total
yield of products 2–4 decreased to 41% (Table 1, entry 3). Other
iron catalysts, namely, Fe(acac)3, Fe(C5H5)2, Fe(OAc)2Á4H2O, and
Fe2(CO)9 were found to catalyze the reaction only upon addition
of an equimolar amount of HBr to give a mixture of products 2
and 3 (Table 1, entries 4–7).
In this Letter we report the amidation of norbornene 1 with
organic nitriles in the presence of water and iron-containing
catalysts.
Initially the reaction was examined using norbornene 1, ace-
tonitrile, and water, stirring at 130 °C for 6 h in the presence of var-
ious iron compounds as the catalyst. The reaction led to a mixture
of three products, namely, N-(exo-2-norbornyl)acetamide 2,
exo-bicyclo[2.2.1]heptan-2-ol 3, and tricyclo[2.2.1.02,6]heptane 4
(Scheme 1) and their yields and the ratios obtained were shown
to be dependent upon the catalyst used (Table 1). The compounds
were all identified using NMR (1H, 13C) spectroscopy and mass-
spectrometry.
The reaction of norbornene with acetonitrile and water in the
presence of FeCl3Á6H2O as the catalyst gave a 10:1 mixture of
N-(exo-2-norbornyl)acetamide 2 and the minor reaction product
exo-bicyclo[2.2.1]heptan-2-ol 3 in 84% total yield (Table 1, entry
Increasing the amount of HBr to 9 mol % (Table 1, entry 8)
resulted in a small increase in the conversion of norbornene 1,
but gave a 1:1 mixture of 2 and tricyclo[2.2.1.02,6]heptane 4 as a
result of the isomerization of 1.
Next the scope of the reaction was examined using other
nitriles such as propionitrile, acrylonitrile, benzonitrile, and
o-tolunitrile which all actively participated in the amidation
reaction (Table 2, entries 1–4).6
Reactions involving these nitriles required higher temperature
(140–145 °C) in comparison with acetonitrile (130 °C), giving the
desired amides 5–8 in isolated yields of 80–95% with by-products
3 and 4 only being formed in trace amounts (Scheme 2).
Other transition and rare earth metal complexes were also
tested as catalysts for the amidation of 1 with organic nitriles
under the optimized reaction conditions. Notably, NiCl2, Ni(acac)2,
RuCl3ÁnH2O, PrCl3, EuCl3Á6H2O, MnCl2, Mn(acac)3, CuCl2Á2H2O,
⇑
Corresponding author. Tel./fax: +7 347 2842750.
E-mail address: khusnutdinovri47@gmail.com (R.I. Khusnutdinov).
http://dx.doi.org/10.1016/j.tetlet.2015.09.131
0040-4039/Ó 2015 Elsevier Ltd. All rights reserved.

R. I. Khusnutdinov, T. M. Oshnyakova / Tetrahedron Letters 56 (2015) 6368–6369
6369
[Fe]
NHCOCH3
OH
+ CH3CN + H2O
+
+
130 °C, 6 h
1
2
3
4
Scheme 1. Amidation of norbornene with acetonitrile catalyzed by iron compounds.
Table 1
References and notes
The effect of the nature of the catalyst on the yield and ratio of the reaction products
in the amidation reaction of norbornene 1 with acetonitrile and water
1. Reddy, B. V. S.; Reddy, N. S.; Madan, Ch.; Yadav, J. S. Tetrahedron Lett. 2010, 51,
4827.
2. Zilberman, E. N. Reactions of Nitriles (in Russian); Khimiya: Moscow, 1972.
Chapter 14.
3. Kazakov, S. A.; Kazantsev, O. A.; Malyshev, A. P. Russ. J. Appl. Chem. 2002, 75,
2029.
4. Kartashov, V. R.; Arkhipova, A. V.; Malkova, K. V.; Sokolova, T. N. Russ. Chem.
Bull., Int. Ed. 2006, 55, 387–389.
Entry
Catalyst
Total yield of 2–4 (%)
Ratio of 2:3:4a
1
2
3
4
5
6
7
8
FeCl3Á6H2O
84
81b
41
20
16
50
38
57
10:1:0
2:1:1
3:0:1
6:1:0
9:1:0
5:1:0
20:1:0
1:0:1
FeCl3Á6H2O
FeCl3
Fe(acac)3–HBr (1:1)
Fe(C5H5)2–HBr (1:1)
Fe(OAc)2Á4H2O–HBr (1:1)
Fe2(CO)9–HBr (1:1)
Fe2(CO)9–HBr (1:3)
5. Bobyleva, A. A.; Petruschenkova, I. A.; Lukovskaya, E. V.; Pehk, T. I.; Dubytskaya,
N. F.; Belikova, N. A. Zhurnal Organicheskoi Khimii 1989, 25, 1428.
6. General procedure for the preparation of N-(exo-2-norbornyl)acylamides: the
amidation of norbornene with organic nitriles was carried out in a 10 mL glass
ampoule. The ampoule was charged with norbornene (0.1 g, 1.06 mmol),
catalyst (0.032 mmol), CH3 CN (8.53 mmol) [or RCN (5.3 mmol)], and water
(0.02 g, 1.06 mmol). The ampoule was sealed, placed into a steel microautoclave,
and heated at 130 °C (140–145 °C for RCN) for 6 h. After reaction completion,
the ampoule was cooled to rt. The reaction mixture was filtered through Al2O3
(eluted with CHCl3), the solvent was removed by distillation, and the residue
recrystallized from CH3CN. N-(exo-2-norbornyl)acetamide (2): mp 140–141 °C
(CH3CN) (Lit. 7 mp 141–142 °C). 1H NMR (400 MHz, CDCl3): d 1.18 (m, 6H), 1.67
(m, 2H), 1.87 (m, 3H), 2.12 (m, 1H), 1.18 (m, 1H), 3.62 (m, 1H), 6.38 (s, 1H). 13C
NMR (100 MHz, CDCl3): d 23.17, 26.47, 28.16, 35.40, 35.59, 39.87, 42.25, 169.50.
MS (EI, 70 eV) m/z (%): 153 [M]+ (31), 138(10), 124(13), 94(64), 43(100). N-(exo-
2-norbornyl)propanamide (5): mp 88–89 °C (CH3 CN). 1H NMR (400 MHz, CDCl3):
d 1.02–1.03 (m, 3H), 1.09–1.68 (m, 8H), 2.09 (s, 1H), 2.16 (s, 1H), 3.61 (s, 1H),
6.04 (s, 1H). 13C NMR (100 MHz, CDCl3): d 9.94, 26.39, 28.07, 29.57, 35.37, 35.53,
39.96, 42.26, 52.51, 173.14. MS (EI, 70 eV) m/z (%): 167 [M]+ (70), 152(2), 139(6),
138(42), 111(42), 110(39), 101(44), 94(100). IR (vaseline oil): mmax 3275, 1661,
1634, 1555 cmÀ1. Found (%): C, 71.83; H, 10.23; N, 8.36. C10H17NO. Calcd. (%): C,
71.81; H, 10.25; N, 8.37. N-(exo-2-norbornyl)acrylamide (6): mp 143–144 °C (CH3
CN). 1H NMR (400 MHz, CDCl3): d 0.88–1.49 (m, 8H), 2.18–2.21 (m, 2H), 3.70–
3.75 (m, 1H), 5.50–5.53 (m, 2H), 6.09–6.21 (m, 1H), 6.40 (s, 1H).13C NMR
(100 MHz, CDCl3): d 26.56, 28.62, 35.54, 35.69, 39.97, 42.38, 52.89, 125.66,
131.39, 164.97. MS (EI, 70 eV) m/z (%): 165[M]+ (23), 150(4), 137(3), 109(50),
108(47), 98(100), 95(5), 94(59). IR (vaseline oil): mmax 3290, 1673, 1654, 1625,
1545 cmÀ1. Found (%): C, 72.68; H, 9.14; N, 8.50. C10H15NO. Calcd. (%): C, 72.69;
H, 9.15; N, 8.48. N-(exo-2-norbornyl)benzamide (7): mp 151 °C (CH3CN) (Lit. 8
mp 150–150.5 °C). 1H NMR (400 MHz, CDCl3)9: d 1.12–1.57 (m, 8H), 1.82–1.87
(m, 1H), 2.29 (s, 1H), 3.88–3.90 (m, 1H), 6.16 (s, 1H), 7.35–7.46 (m, 3H), 7.72 (d,
J = 7.6 Hz, 2H). 13C NMR (100 MHz, CDCl3)9: d 26.60, 28.23, 35.72, 35.82, 40.47,
42.49, 53.41, 126.94, 128.50, 131.24, 135.05, 166.90. MS (EI, 70 eV) m/z (%): 215
[M]+(20), 148(8), 135(6), 134(8), 122(16), 105(100), 94(6). N-(exo-2-norbornyl)
methylbenzamide (8): mp 145–146 °C (CH3 CN). 1H NMR (400 MHz, CDCl3): d
1.15–1.94 (m, 8H), 2.31–2.33 (m, 1H), 2.43 (s, 3H), 2.55 (s, 1H), 3.87–3.92 (m,
1H), 5.75 (s, 1H), 7.16–7.32 (m, 4H). 13C NMR (100 MHz, CDCl3): d 19.75, 26.56,
28.22, 35.70, 35.81, 40.45, 42.57, 52.15, 125.71, 126.71, 129.67, 130.92, 135.88,
136.92, 169.38. MS (EI, 70 eV) m/z (%): 229[M]+(27), 136(6), 134(12), 120(14),
119(100), 94(6), 91(50). IR (vaseline oil): mmax 3280, 1632, 1599, 1536 cmÀ1.).
Found (%): C, 78.55; H, 8.35; N, 6.13. C15H19NO. Calcd. (%): C, 78.56; H, 8.35; N,
6.11.
Reaction conditions: catalyst (0.032 mmol), 1 (1.06 mmol), CH3CN (8.53 mmol),
H2O (1.06 mmol), 130 °C, 6 h.
a
Ratio determined by GLC using undecane as an internal standard.
Reaction temperature 140 °C.
b
Table 2
The effect of the structure of nitrile on the yield of the reaction product
Entry
R
Product
Isolated yield (%)
1
2
3
4
Et
5
6
7
8
90
80
90
95
H2C@CHA
Ph
o-Tol
Reaction conditions: FeCl3Á6H2O (0.032 mmol), 1 (1.06 mmol), RCN (5.3 mmol), H2O
(1.06 mmol), 140–145 °C, 6 h.
FeCl3•6H2O
NHCOR
+ RCN + H2O
140-145 °C, 6 h, 80-95%
1
5-8
Scheme 2. Reaction of norbornene with organic nitriles and water catalyzed by
FeCl3Á6H2O.
MoO2(acac)2, and Mo(CO)6 did not show marked activity toward
this reaction.
In conclusion, we have developed a new catalytic method for
the amidation of norbornene 1 using organic nitriles in the pres-
ence of water and FeCl3Á6H2O.
7. Chambers, R. D.; Kenwright, A. M.; Parsons, M.; Sandford, G.; Moilliet, J. S. J.
Chem. Soc., Perkin Trans. 1 2002, 2190.
Acknowledgement
8. Newton, M. G.; Pantaleo, N. S.; Kirbawy, S.; Allinger, N. L. J. Am. Chem. Soc. 1978,
100, 2176.
9. Aufdenblatten, R.; Diezi, S.; Togni, A. Monatsh. Chem. 2000, 131, 1345.
The work was financially supported by the Russian Foundation
for Basic Research (Grant No. 14-03-97029 r_povolzh’e_a).
Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.tetlet.2015.09.
131.