Anaswara RAVINDRAN et al. / Chinese Journal of Catalysis, 2011, 32: 1597–1603
maceutically important organic derivatives, in particular, the
almost pure form. The product was further purified by
re-crystallization from ethanol/H2O. The compounds were
characterized by IR, 1H NMR (CDCl3), elemental analysis and
melting point, and the results matched well with the reported
values [20].
synthesis of N-[(2-hydroxy-naphthalen-1-yl)-aryl-methyl]-
benzamide/urea (3-component coupling product of aromatic
aldehyde, ȕ-naphthol, and benzamide/urea), 1-(aryl (piperidin-
1-yl) methyl) naphthalen-2-ol (3-component coupling product
of aromatic aldehyde, ȕ-naphthol, and piperidine), and
5-(ethoxycarbonyl)-6-methyl-4-aryl-3, 4-dihydropyrimidin-
2(1H)-one (3-component coupling product of aromatic alde-
hyde, ethylacetoacetate, and urea).
N-[(2-hydroxynaphthalen-1-yl)-phenylmethyl]-benzamide.
Mp 233–235 qC. IR (KBr, ȣ, cm–1): 3422, 3064, 3023, 1628,
1
1576, 1530, 1438, 1345, 1270, 826. H NMR (200 MHz,
DMSO-d6) į 5.32 (br s, 1H), 5.78 (br s, 1H), 7.24–8.13 (m,
16H), 10.04 (s, 1H); Elemental analysis for C24H19NO2: (%) C
81.81, H 5.12, N 3.77 (theoretical: C 81.58, H 5.38, N 3.96).
1 Experimental
N-[(2-hydroxynaphthalen-1-yl)-phenylmethyl]-urea.
Mp
1.1 Catalyst preparation
175–177 qC. IR (KBr, ȣ, cm–1): 3455, 3360, 3200, 2240, 1630,
1
1580, 1510, 1426, 1372, 1238, 814. H NMR (200 MHz,
In a typical synthesis, 0.01 mol potassium ferrocyanide,
(K4[Fe(CN)6]3H2O, Merck, India) was dissolved in 40 ml
double-distilled water to prepare solution 1. In a separate
beaker, solution 2 was prepared by dissolving 0.1 mol metal
chloride salts (ZnCl2, MnCl2·4H2O, NiCl2·6H2O, CoCl2·6H2O,
and FeCl24H2O) in 100 ml distilled water and 20 ml t-BuOH.
Polyethylene glycol (15 g, PEG-4000) was dissolved in a third
beaker containing 2 ml distilled water and 40 ml t-BuOH to
prepare solution 3. Solution 2 was added to solution 1 slowly
over 1 h at 323 K under vigorous stirring. Precipitation of a
solid occurred during the addition. To the reaction mixture,
solution 3 was added over 5–10 minutes and stirring was con-
tinued for another 1 h. The solid that was formed was filtered
and washed thoroughly with 500 ml double-distilled water to
remove uncomplexed ions, and dried at 398 K for several
hours. The DMC catalysts prepared with K4[Fe(CN)6] and
different metal chlorides were designated as Fe-Zn-PEG,
Fe-Mn-PEG, Fe-Ni-PEG, Fe-Co-PEG, and Fe-Fe-PEG. The
colors of these catalysts were: Fe-Zn-PEG (white), Fe-Fe-PEG
(dark blue), Fe-Mn-PEG (light green), Fe-Ni-PEG (olive
green), and Fe-Co-PEG (brown). t-BuOH acted as a com-
plexing agent and PEG-4000 acted as a co-complexing agent.
DMSO-d6) į 5.30 (br s, 1H), 5.72 (br s, 1H), 6.91 (br s, 2H),
7.12–7.82 (m, 11H), 10.25 (s, 1H); Elemental analysis for
C18H16N2O2: (%): C 74.39, H 5.39, N 9.32 (theoretical: C
73.96, H 5.52, N 9.58).
1.2.2 Synthesis of 1-(aryl-(piperidin-1-yl) methyl)
naphthalen-2-ol (Betti base)
A mixture of ȕ-naphthol (10 mmol), aldehyde (13 mmol),
piperidine (10 mmol), and catalyst (0.5 mmol) was stirred in
the presence of water (15 ml) at 298 K for the desired time. The
progress of the reaction was monitored by TLC. After 4 h of
reaction, the reaction mixture was extracted by ethyl acetate.
The aqueous phase was back-extracted with ethyl acetate. The
combined organic layers were dried over anhydrous Na2SO4,
filtered, and concentrated under reduced pressure to get the
crude product as a white solid which was purified by column
chromatography using silica gel (60-120) as the stationary
phase with hexane/ethyl acetate (95/5). The compounds were
characterized by IR, 1H NMR, elemental analysis, and melting
point and the results matched well with the reported values
[21].
Mp 180–181 qC. IR (KBr, ȣ, cm–1): 3057, 2942, 2844, 1621,
1
1.2 Catalytic reactions
1450, 751. H NMR (200 MHz, CDCl3) į 1.66 (br s, 6H),
2.43–2.53 (br s, 4H), 5.07 (s, 1H), 7.05–7.81 (m, 10H), 7.85
(d,J = 8.4 Hz, 1H), 10.01 (s, 1H); Elemental analysis for
C22H23NO: (%) C 83.41, H 7.18, N 4.31 (Theoretical: C 83.28,
H 7.25, N 4.41).
1.2.1 Synthesis of N-[(2-hydroxynaphthalen-1-yl)-aryl-
methyl]-benzamide and N-[(2-hydroxynaphthalen-1-yl)-
aryl-methyl]-urea
A mixture of ȕ-naphthol (10 mmol), aldehyde (10 mmol),
benzamide/urea (12 mmol), and catalyst (0.5 mmol) was stirred
in the presence of 1,2-dichloroethane (15 ml) at 353 K for the
desired time. The progress of the reaction was monitored by
thin layer chromatography (TLC). 1,2-dichloroethane (30 ml)
was added into the reaction mixture, and the catalyst was fil-
tered and washed with chloroform for reuse. The organic layer
was successively washed with water (30 ml), sat. NaHCO3 (30
ml), water (30 ml) and then dried over anhydrous sodium sul-
fate. The solvent was evaporated to get the crude compound in
1.2.3 Synthesis of 5-(ethoxycarbonyl)-6-methyl-4-
aryl-3,4-dihydropyrimidin-2(1H)one
In a typical synthesis, aldehyde (10 mmol), urea (15 mmol),
ethylacetoacetate (10 mmol), catalyst (0.5 mmol), and ace-
tonitrile (10 ml) were mixed in a 100 ml flask. The reaction was
conducted at 353 K for 12 h. After completion of the reaction,
the catalyst was removed by simple filtration/decantation. The
products were isolated by flash column chromatography (pe-
troleum ether/ethyl acetate = 3). The compounds were char-