F. Tamaddon et al. / Tetrahedron Letters 48 (2007) 3643–3646
3645
Table 2 (continued)
0
c
Entry
R
R
Temperature (ꢁC)
Product
Time (h)/yield (%)
References
5
13
Ph
Cl
CH2
90
CH NHCOPhd
4.5/84
Cl
2
14
15
16
Ph
C@C
C@C
(CH
(CH
PhCH
3
)
)
3
C–
C–
100
90
90
(CH
(CH
PhCH
3
)
)
3
C–NHCOPh
C–NHCOCH@CH
NHCOCH@CH
2.5/92
3/88
3/90
30
28
6
3
3
3
3
2
2
2
2
1
1
7
8
C@C
C@C
MeO
CH2
80
90
MeO
CH NHCOCH=CH
3/89
4/93
28
28
2
2
Cl
CH2
Cl
CH NHCOCH=CH
2
2
1
2
9
0
CNCH
CNCH
2
–
–
(CH
PhCH
3
)
3
C
80
80
(CH
3
)
3
CNHCOCH
2
CONHC(CH
3
)
3
3/89
—
28
—
2
2
Mixture of products
a
2 5 2
The alcoholic substrate (1 mmol) was stirred with nitrile (1 mmol) in the presence of 0.2 g of freshly prepared P O /SiO (60% w/w) under neat
conditions at 50–100 ꢁC.
Acetonitrile (1.2 mmol) was used.
Isolated yields.
b
c
d
These alcohols underwent microwave assisted Ritter reaction using an unmodified domestic MW oven at 475 W for 120 s and produced the
corresponding amides in comparable yields to thermal conditions. All products are known and were identified by their melting points, IR and in
1
some cases H NMR spectra.
O
2
. Samguigni, J. A.; Levins, R. J. Med. Chem. 1964, 7,
CH CNHCH Ph (0%)
573.
H C C
N
N
3
2
3
o
1
mmol
80
5
C
3. Garcia Martinez, A.; Martinez Alvarez, R.; Teso Vilar, E.;
Garcia Fraile, A.; Hanach, M.; Subramanian, L. R.
Tetrahedron Lett. 1989, 30, 581.
. Firouzabadi, H.; Sardarian, A. R.; Badparva, H. Synth.
Commun. 1994, 601.
+
PhCH
2
OH
O
h.
1
mmol
Ph
1
C
mmol
PhCNHCH Ph (85%)
2
4
5
6
7
8
Scheme 2.
. Salehi, P.; Rostamian Motlagh, A. Synth. Commun. 2000,
6
71.
. Sharghi, H.; Niknam, Kh. Iran J. Chem. Chem. Eng. 1999,
8, 36.
. Olah, G. A.; Yamato, T.; Lyer, S. Mater. Chem. Phys.
987, 17, 21.
tures. The results obtained show that P O /SiO (60%
2
5
2
w/w) provides an excellent heterogeneous media for
the Ritter reaction both under thermal conditions or
microwave irradiation.
1
1
. (a) Mukhopadhyay, M.; Reddy, M. M.; Maikap, G. C.;
Iqbal, J. J. Org. Chem. 1995, 60, 2670; (b) Mukhopad-
hyay, M.; Iqbal, J. J. Org. Chem. 1995, 62, 1843.
Additionally, the chemoselectivity of the reaction was
evaluated via competitive P O /SiO -catalyzed Ritter
2
5
2
reaction of benzyl alcohol (1 mmol) with a mixture of
benzonitrile and acetonitrile. It was found that benzonit-
rile reacted with benzyl alcohol in high yield and selec-
tively in the presence of acetonitrile and that the
reaction temperature extensively affected the chemo-
selectivity (Scheme 2). However, no chemoselectivity
was observed for benzyl alcohol versus benzhydrol.
9. Lakourag, M. M.; Movassagh, B.; Fasihi, J. Synth.
Commun. 2000, 821.
1
0. Okuhara, T.; Chen, X.; Matsuda, H. Appl. Catal. A: Gen.
2
000, 200, 109.
1
1
1. Chen, X.; Okuhara, T. J. Catal. 2002, 207, 194.
2. (a) Baraznenok, I. L.; Nenajdenko, V. G.; Balenkova, E.
S. Tetrahedron 2000, 56, 3077; (b) Justribo, V.; Colombo,
M. I. Tetrahedron Lett. 2003, 44, 8023.
1
3. Barton, D. H. R.; Magnus, P. D.; Garbarino, J. A.;
Young, R. N. J. Chem. Soc., Perkin Trans. 1 1974, 2101.
In conclusion, this simple efficient P O /SiO -catalyzed
2
5
2
Ritter reaction offers several advantages including gen-
erality and simplicity, easy work up, clean reactions,
scale up, selectivity and improved yields.
14. Reddy, K. L. Tetrahedron Lett. 2003, 44, 1453.
15. Chen, H. G.; Goel, O. P.; Kesten, S.; Knobelsdrof, J.
Tetrahedron Lett. 1996, 37, 8129.
1
6. Tamaddon, F.; Amrollahi, M. A.; Sharafat, L. Tetrahe-
dron Lett. 2005, 46, 7841.
Acknowledgement
17. (a) Eshghi, H.; Rafei, M.; Karimi, M. Synth. Commun.
001, 771; (b) Hajipour, A. R.; Zarei, A.; Khazdooz, L.;
2
We are grateful to the Research council of Yazd Univer-
sity for financial support.
Pourmoousavi, S. A.; Mirjalili, B. F.; Ruoho, A. E.
Phosphorus Sulfur Silicon 2005, 180, 2029.
8. Eshghi, H.; Rafei, M.; Gordi, Z.; Bohloli, M. J. Chem.
Res. (s) 2003, 12, 763.
1
References and notes
19. (a) Eshghi, H.; Gordi, Z. Phosphorus Sulfur Silicon 2005,
80, 1553; (b) Eshghi, H.; Shafieyoon, P. J. Chin. Chem.
1
1
. (a) Ritter, J. J.; Minieri, P. P. J. Am. Chem. Soc. 1948, 70,
Soc. 2005, 52, 155.
4
1
045; (b) Benson, F. R.; Ritter, J. J. J. Am. Chem. Soc.
949, 71, 4128.
20. Eshghi, H.; Shafieyoon, P. Phosphorous Sulfur Silicon
2004, 179, 2149.