G Model
CRAS2C-3885; No. of Pages 6
H. Eshghi et al. / C. R. Chimie xxx (2014) xxx–xxx
3
3.10. (Z)-3-{3-[(Z)-1-Methyl-3-oxo-3-phenyl-1-propenyl
amino] propyl amino}-1-phenyl-2-buten-1-one (3j)
Yield 100%; mp = 86–88 8C; 1H NMR (CDCl3, 100 MHz)
d
: 11.5 (b, 2H), 7.3-7.9 (m, 10H), 5.65 (s, 2H), 3.35–3.6 (m,
4H), 2.1 (s, 6H). IR (KBr, cmꢁ1
) y: 3342, 3227, 1607, 1551,
1521, 1308, 1279.
4. Results and discussion
Cm -1
This paper reports for the first time a regio-and chemo-
selective bis-enamination of -dicarbonyl compounds
Fe(HSO4)3
Fe2(SO4)3.XH2O
b
under solvent-free conditions using Fe(HSO4)3ꢀSiO2 at
room temperature in excellent yields and purity. Silica-
supported ferric hydrogensulfate was prepared from
Fe(HSO4)3 [34] and silica gel as we previously reported
[35]. IR spectra of Fe(HSO4)3 and Fe2(SO4)3ꢀx H2O were
compared as shown in Fig. 1. As can be seen, the IR
spectrum of Fe(HSO4)3 is clearly different from that of
Fe2(SO4)3ꢀx H2O. The atomic absorption analysis spectrum
shows that the expected percentage of Fe has been
recovered, whereas the titration of the aqueous solution
of Fe(HSO4)3 with NaOH did not show significant
contamination of the catalyst with H2SO4.
Fig. 1. Comparison of IR spectra of Fe(HSO4)3 and Fe2(SO4)3ꢀx H2O.
3.6. (2Z,20Z)-Dimethyl 3,30-(1,4-
phenylenebis(azanediyl))bis(but-2-enoate) (3f)
Yield50%;mp = 149–150 8C;1HNMR(CDCl3, 100 MHz)
d:
10.2(b,2H),6.5-7.3(m,4H),5.0(s,2H),3.65(s,6H),1.9(s,6H).
IR (KBr, cmꢁ1
: 3268, 2937, 1662, 1600, 1257, 1161, 789.
)
y
3.7. (2Z,20Z)-Dimethyl 3,30-(propane-1,3-
diylbis(azanediyl))bis(but-2-enoate) (3g)
Initially, the condensation of ethylene diamine with
2 equiv of acetylacetone was selected as a model reaction,
and the influence of various reaction parameters, like
catalyst, temperature and time, on the isolated yield of 3a
was examined (Scheme 1, Table 1). Fe(HSO4)3ꢀSiO2 proved
to be the most efficient catalyst because the reaction could
be carried out in excellent yield and short reaction time
under solvent-free conditions. The best reaction conditions
require the presence of a catalytic amount of Fe(H-
SO4)3ꢀSiO2 (12.5 mol%) under solvent-free conditions at
room temperature.
A variety of diamines, including aliphatic and aromatic
diamines were condensed with various 1,3-dicarbonyl
compounds, such as acetylacetone, benzoylacetone and
methyl acetoacetate. (Scheme 1). The results are summar-
ized in Table 2.
Yield 100%; mp = 54–56 8C; 1H NMR (CDCl3, 100 MHz)
d
: 8.5 (b, 2H), 4.45 (s, 2H), 3.6 (s, 6H), 3.2–3.8 (m, 6H), 1.9 (s,
6H). IR (KBr, cmꢁ1
1169, 1132.
) y: 3284, 2949, 1656, 1603, 1310, 1263,
3.8. (Z)-3-{2-[(Z)-1-Methyl-3-oxo-3-phenyl-1-propenyl
amino] ethyl amino}-1-phenyl-2-buten-1-one (3h)
Yield 72%; mp = 179–181 8C, lit. [19] mp 178–180 8C; 1H
NMR (CDCl3, 100 MHz) d: 11.6 (b, 2H), 7.3–7.9 (m, 10H), 5.7
(s, 2H), 3.6–3.7 (m, 4H), 2.1 (s, 6H). IR (KBr, cmꢁ1
3227, 1607, 1551, 1521, 1308, 1279.
) y: 3342,
3.9. (Z)-3-{2-[(Z)-1-Methyl-3-oxo-3-phenyl-1-propenyl
amino] anilino}-1-phenyl-2-buten-1-one (3i)
Yield 80%; mp = 148–150 8C; 1H NMR (CDCl3, 100 MHz)
: 12.2 (b, 2H), 6.7–7.9 (m, 14H), 5.5 (s, 2H), 1.95 (s, 6H). IR
(KBr, cmꢁ1
) y: 3325, 3223, 1596, 1574, 1543, 1324, 1278.
It is clear from our results that silica ferric hydro-
gensulfate catalyzed the condensation reaction of 1,3-
dicarbonyls with diamines, providing a remarkably rapid
d
Table 1
Optimization conditions of the reaction between ethylene diamine and acetylacetone.
Entry
Solvent
Catalyst
Mol%
Condition
Yield (%)
1
CH3OH
Fe(HSO4)3
10
Reflux, 1 h
RT, 1 h
45
48
70
5
2
CH3OH
Fe(HSO4)3
12.5
5
3
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Solvent-free
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
Fe(HSO4)3/SiO2
RT, 30 min
RT, 60 min
RT, 15 min
RT, 15 min
RT, 15 min
RT, 15 min
RT, 15 min
RT, 15 min
RT, 15vmin
RT, 45 min
4
0
5a
6
12.5
20
90
91
90
88
85
85
80
80
7b
8b
9b
10b
11b
12b
12.5
12.5
12.5
12.5
12.5
12.5
RT: room temperature.
a
Optimum conditions.
b
Reusability of the catalyst in the new runs.
Please cite this article in press as: Eshghi H, et al. Fe(HSO4)3ꢀSiO2 as an efficient, heterogeneous and recyclable catalyst