1
812
J. Tian, L. Li, X. Yan, and L. Chen
Vol 51
Scheme 1. Synthesis of 3-methylindolin-2-one.
Scheme 4. Friedel–Crafts alkylation of N-phenylacrylamide.
O
NH2
Cl
HN
HN
HN
HN
O
Cl
AlCl3
Cl
O
O
O
Scheme 5. Generation mechanism of 3,4-dihydro-2(1H)-quinolinone.
HN
AlCl3
AlCl3
AlCl3
Cl
O
AlCl3
O
O
O
HN
HN
HN
HN
HN
HN
H
AlCl3
AlCl3
H
AlCl3
H
O
O
O
HN
HN
N-Phenylacrylamide
3, 4-dihydro-2(1H) - quinolinone
Figure 1. The structures of two byproducts.
ꢀ
dropwise at 0–5 C. And the mixture was stirred for additional 2 h
ꢀ
at 0–5 C. Then, the precipitate was separated by filtration and
washed with dichloromethane. The organic phases were combined
and concentrated. The residue was washed successively with HCl
Scheme 2. The generation mechanism of 3-methylindoline-2-one.
O
O
(
2mol/L) and water and then was dried under vacuum.
1
N-(2-Chloroacetyl)aniline. Yield: 90.2%. H-NMR (400 MHz,
HN
HN
HN
ꢀ
complexation
CDCl
, 25 C): d ppm 4.22 (s, 2H), 7.20 (t, 1H, J = 7.40 Hz),
Cl
3
H
AlCl3
7
.37–7.40 (m, 2H), 7.57 (d, 2H, J = 7.89 Hz), 8.26 (br, s).
1
3
ꢀ
C-NMR (100 MHz, CDCl , 25 C): d ppm 42.88, 120.13,
3
C
O
O
O
125.26, 129.15, 136.68, 163.76.
1
HN
HN
N-(2-Chloropropionyl)aniline.
Yield 95.5%. H-NMR
aromatization
ꢀ
(
400 MHz, CDCl , 25 C): d ppm 1.84 ( d, 3H, J = 7.07 Hz ),
3
H
H
4
.56 (q, 1H, J = 4.56 Hz), 7.17 (t, 1H, J = 7.43 Hz ), 7.34–7.37
13
(
m, 2H), 7.56 (d, 2H, J = 8.62 Hz), 8.29 (br, s). C-NMR
ꢀ
(
100 MHz, CDCl
3
, 25 C): d
C
ppm 22.55, 56.07, 120.19,
1
25.08, 129.10, 137.02, 167.63.
1
N-Phenylacrylamide.
Yield: 88.3%. H-NMR (400 MHz,
Scheme 3. The generation mechanism of N-phenylacrylamide.
ꢀ
CDCl , 25 C): d ppm 5.76 (dd, 1H, J = 1.26 Hz, J = 1.27 Hz),
3
H
O
O
6
.31 (dd, 1H, J = 10.18 Hz, J = 10.19 Hz), 6.45 (dd, 1H,
J = 0.88 Hz, J = 0.90 Hz), 7.13 (t, 1H, J = 7.35 Hz), 7.31–7.34
m, 2H, J = 7.70 Hz, J = 8.15 Hz), 7.61 (d, 2H, J = 7.80 Hz),
HN
H
HN
(
13
ꢀ
-HCl
7.68 (br, s). C-NMR (100 MHz, CDCl , 25 C): d ppm
3
C
1
20.43, 124.57, 127.60, 128.96, 131.40, 137.93, 164.27.
General procedures for the cyclization of N-acyl-anilines. At
the ambient temperature, aluminum chloride (0.06 mol) was added in
small portions to the N-acyl-anilines (0.03 mol) with vigorously
stirring under the atmosphere of an inert gas (N gas) in half an
2
EXPERIMENTAL
Unless otherwise noted, all reagents and solvents were purchased
hour. Subsequently, the compounds were continually stirred with
from Tianjin Guangfu Chemical Co., Ltd. Commercial grade ani-
line and acyl chloride were purified by distillation before use.
Dichloromethane was dried with CaH2 and then distilled. All
reactions were monitored by TLC. Column chromatography was
ꢀ
heating at 160 C for 4 h. After the reaction was completed, the
mixture was cooled on ice and added with a small volume of ice
cold water while stirring. The aqueous phase obtained was
extracted three times with dichloromethane. The organic phases
were combined together, washed successively with saturated
1
13
performed using 200–300mesh silica gel. H-NMR and C-NMR
spectra were recorded in CDCl (Cambridge Isotope laboratories)
on a Bruker 400 spectrometer using TMS as internal standard.
3
NaHCO and water and then dried with anhydrous MgSO . After
3 4
General procedures for the synthesis of amides.
stirred solution of aniline (0.11 mol) in dichloromethane (100mL),
acyl chloride (0.05 mol) in dichloromethane (30 mL) was added
To a
filtration, the organic phase was evaporated to give the crude
product that was then purified by silica gel column chromatography
( petroleum ether–ethyl acetate = 3:1).
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet