N-donor ligand as catalyst: A simple Aza-Michael addition reaction in aqueous media

Article abstract of DOI:10.1002/jhet.5570450650

(Chemical Equation Presented) A novel approach for the Aza-Michael addition reactions between various amines and α,β-unsaturated esters, nitriles and ketones using N-donor Ligand catalyst (3 mol %) is described. The reactions are carried out in aqueous media at an ambient temperature to afford the products in excellent yields.

Full text of DOI:10.1002/jhet.5570450650

Nov-Dec 2008
N-donor Ligand as Catalyst: A Simple Aza-Michael Addition
Reaction in Aqueous Media
1869
a
a
b
Shivaji S. Pawar, Deepak V. Dekhane, Murlidhar S. Shingare,
a
Shivaji N. Thore*
a
Department of Chemistry, Vinyakrao Patil Mahavidyala Vaijapur,
Aurangabad- 423701 (M.S.), India
Department of Chemistry, Dr. Babasaheb Ambedkar Marathwada University,
Aurangabad- 431004 (M.S.), India.
b
Received December 22, 2007
N-donor Ligand
NH +
X
N
rt, 20-40 min, water
X
9
0-95%
Where X = COOMe, COOEt, CN, COMe.
H
N
SO Na
3
N-donor Ligand =
N
1
A novel approach for the Aza-Michael addition reactions between various amines and ꢀ,ꢁ-unsaturated
esters, nitriles and ketones using N-donor Ligand catalyst (3 mol %) is described. The reactions are carried
out in aqueous media at an ambient temperature to afford the products in excellent yields.
J. Heterocyclic Chem., 45, 1869 (2008).
INTRODUCTION
various metal catalysts, such as Yb(OTf)3,
InCl3,
CeCl .7H O/NaI, Bi(NO)3, Bi(OTf)3, Cu(OTf)2,
3
2
Conjugate addition (Michael addition) of nucleophiles
to ꢀ,ꢁ-unsaturated carbonyl compounds is one of the most
important bond forming strategies in synthetic organic
chemistry [1]. The versatility of the conjugate addition is
due to the large variety of nucleophiles (organometallic
reagents, other carbanions, heteroatoms, Michael donors)
and acceptors (ꢀ,ꢁ-unsaturated carbonyl compounds,
esters, nitriles and notroalkenes) that can be used [2].
Among the variety of synthetic transformations, the
development of new methods for new and efficient
conjugate addition reactions with a wide range of
heteroatom nucleophiles has attracted special attention
FeCl .7H O/Co(OAc) LiClO heterogeneous solid acids,
3
2
2,
4,
ionic liquids, quaternary ammonium salts, Cu(acac)2
immobilized in ionic liquids have efficiently catalyzed the
aza-Michael reaction [6]. Unfortunately many of these
procedures requires a large excess of reagents, long
reaction times and drastic reaction conditions in
acetonitrile or 1,2-dichloroethane which are very high on
the list of damaging chemicals. In some cases
stoichiometric amounts of Lewis acids such as AlCl3,
TiCl or SnCl are required. These conditions are not in
3
4
agreement with clean chemistry, and hence the challenge
for a sustainable environment calls for the use of
alternative procedures avoiding the use of harmful
solvents and reagents. Thus, the need for an
environmentally benign and facile protocol for the aza-
Michael reaction still exists.
[
3]. In particular, the conjugate addition of nitrogen
nucleophiles to ꢀ,ꢁ-enones (aza-Michael reaction) is
noteworthy as a widely used method for carbon-nitrogen
bond formation. The products of aza-Michael additions,
ꢁ
-amino carbonyl compounds and derivatives, can be
Organic reactions in water or aqueous media have
attracted great interest [7]. With tightened regulatory
pressure focusing on organic solvents, the search for
alternatives is of increasing importance. In this respect,
the development of water-tolerant catalysts has rapidly
become an area of intense research. Surprisingly,
however, there are few reports on the conjugate addition
of nitrogen nucleophiles to ꢀ,ꢁ-unsaturated carbonyl
used in peptide analogues or as precursors to optically
active amino acids, amino alcohols, diamines and lactams,
many of which serve as powerful antibiotics or other
drugs [4]. Among the methods for generating ꢁ-amino
carbonyl compounds, Lewis acid and base catalyzed
conjugate addition of nitrogen containing nucleophiles to
ꢀ
, ꢁ-unsaturated carbonyl compounds is one of the most
simple and effective methods [5]. To avoid typical
disadvantages resulting from the presence of such protic
catalysts, a good number of alternative procedures have
been developed over the past few years. In particular,
compounds in water [6b,6g,6h,6l].
These findings
promoted us to investigate the aza-Michael reaction in
aqueous media, in continuation of our interest in

1
870
S. S. Pawar, D. V. Dekhane, M. S. Shingare, S. N. Thore
Vol 45
developing novel synthetic methodologies, particularly
carbon-carbon and carbon-heteroatom bond formations
Table 1
Aza-Michael addition reaction between piperidine and methyl acrylate
a
using different solvents.
[
6f,6n,8].
Reaction
time (min)
Yield
(%)
RESULTS AND DISCUSSION
As a part of our ongoing project [9], we have developed
methodology for the aza-Michael addition reaction, which
makes use of milder conditions over the reported
procedure as depicted in Scheme 1.
Entry
Reagent
Solvent
DCM
CH CN
3
THF
b
1
2
3
4
5
6
1
1
1
1
1
1
180
150
120
150
120
130
35
45
40
50
45
50
CHCl
3
DMSO
DMF
CH
3
CN/H
1:1)
2
O
Scheme-1
7
8
9
1
1
90
60
67
60
(
N-donor Ligand
THF/H O
2
NH
+
X
N
(1:1)
rt, 20-40 min, water
X
DCM/H
1:1)
2
O
1
1
90
20
70
95
(
1
0
2
H O
Where X = COOMe, COOEt, CN, COMe.
a
Standard conditions: 1 mmol methyl acrylate, 1.1 mmol piperidine, 3
Amines =
NH
NH
O
NH
NH
b
mol % catalyst (1), water, rt; Isolated yields.
H
N
In a typical experiment, the conjugate addition of
piperidine to methyl acrylate in water was carried in the
presence of N-donor ligand (1) to afford the
corresponding (1- piperidinyl)-propionic acid methyl ester
in 95% yield. The reaction proceeds rapidly at ambient
temperature with 3 mol % of catalyst (1) and completes
within 20 min (Table 1, entry 10). The use of different
SO Na
3
N-donor Ligand =
N
(1)
The methodology developed is simple with good to
excellent yields. N-Donor ligand was synthesized by
reacting 3-(2-aminoethyl)pyridine with sodium vinyl-
sulfonate in water using a literature procedure [10]. We
first compared the catalyst effect on different solvents for
the aza-Michael addition reactions, and the results are
summarized in Table 1.
solvents like CH CN, THF, CHCl , DMSO and DCM
3 3
afforded very low yields (Table 1, entry 1-6). However,
the addition of water to the above solvents gave slightly
higher yields (Table 1, entry 7-9). These results suggest
Table 2.
N- Donor ligand (1)-catalyzed aza-Michael addition reaction between amines and ꢀ, ꢁ-unsaturated carbonyl compounds or nitriles
ꢀ
,ꢁ-unsaturated carbonyl
a
b
Entry
1
Amines
Product
Time
20
Yield
95
compounds or nitriles
OMe
O
O
NH
N
OMe
(A)
OEt
O
O
2
3
25
25
93
94
NH
N
OEt
(
B)
O
NH
O
N
(C)
CN
4
5
CN
N
30
25
90
91
NH
(D)
OMe
O
O
NH
N
OMe
O
O
O
(
E)
OEt
O
O
6
7
35
30
91
92
O
NH
N
OEt
(F)
O
O
NH
O
N
(G)

Nov-Dec 2008
N-donor Ligand as Catalyst: A Simple Aza-Michael Addition Reaction in Aqueous Media
1871
Table 2 (continued)
ꢀ
,ꢁ-unsaturated carbonyl
a
b
Entry
8
Amines
Product
Time
25
Yield
94
compounds or nitriles
CN
CN
N
O
O
NH
(H)
OMe
O
O
9
20
35
94
93
NH
N
OMe
(
I)
OEt
O
O
1
1
0
1
NH
N
OEt
(
J)
O
25
92
NH
O
N
(
K)
CN
1
1
2
3
CN
N
30
25
93
95
NH
(
L)
OMe
O
O
NH
N
OMe
(M)
OEt
O
O
1
1
4
5
6
25
25
40
94
95
90
NH
NH
NH
N
OEt
(
N)
O
O
N
(
O)
CN
1
CN
N
(
P)
a
b
2
All the reactions were performed in H O as solvent at room temperature; Isolated yields
that water is the best solvent for aza-Michael addition
reaction. It may be due to the fact that N-donor ligands
have greater solubility and greater basicity in water than
in organic solvents.
following abbreviations are used; singlet (s), doublet (d), triplet
t), quartet (q), multiplet (m) and broad (b). Mass spectra were
Micromass-QUATTRO-II of WATER mass spectrometer. IR
spectra were measured with Bruker Vector 22 FTIR
(
a
spectrophotometer. All chemicals were obtained from
commercial suppliers and were used without purification.
Typical Procedure for aza-Michael addition reaction in
aqueous media. The appropriate amine (1 mmol) and ꢀ,ꢁ-
unsaturated carbonyl compound (1.1 mmol) were added to a 25
mL conical flask containing 10 mL water and to this 3 mol % of
N-donor ligand (1) was added. The reaction mixture was stirred
at room temperature for 20 min. The progress of the reaction
was monitored using TLC. Upon completion, the reaction
mixture was extracted with diethyl ether (10 mL x 2) and the
organic layer was dried over anhydrous sodium sulphate.
Filtration and evaporation under reduced pressure afforded a
residue that was purified by column chromatography (60-120
mesh silica gel, 5% ethyl acetate in hexane).
With optimum conditions in hand, we reacted various
amines such as piperidine, morpholine, diethyl amine and
dimethyamine with a variety of ꢀ, ꢁ- unsaturated carbonyl
compounds such as methyl acrylate, ethyl acrylate,
acrylonitrile and methyl vinyl ketone. The corresponding
1
,4 addition aza-Michael products were formed in good to
excellent yields (90-95%). All the reactions were
completed within 20-40 minutes, and all the products
1
were confirmed by H NMR, IR and mass spectroscopy
and results are summarized in Table 2.
In conclusion, the N-donor ligand provides an efficient
methodology for the synthesis of ꢁ-amino carbonyl
compounds via aza-Michael reaction. The remarkable
advantages offered by this method are a simple procedure,
mild conditions, fast reactions and excellent yields of
products.
3-(1-Piperidinyl)-propionic acid methyl ester (A) [6p].
-1 1
Colorless oil; IR (KBr): 2935, 1737, 1168 cm ; H NMR (CDCl
,
3
4
00 MHz, ꢂ, ppm): 3.66 (s, 3H, -OCH ), 2.69 (t, 2H, J=7.40 Hz,
3
N-CH ), 2.55 (t, 2H, J=7.40 Hz, -CH -C=O), 2.42 (m, 4H, N-
2
2
1
3
CH ), 1.59 (m, 4H, CH ), 1.42 (m, 2H, CH ); C NMR (CDCl3,
2
2
2
1
00 MHz, ꢂ, ppm): 173.3 (-O-C=O), 54.4 (N-CH ), 51.7 (-OCH ,
2 3
EXPERIMENTAL
N-CH ), 32.1 (CH -C=O), 26.0 (-CH ), 24.4 (-CH ); MS (EI, 70
eV): m/z = 172 [M+H] ; Anal. Calcd for C H NO : C, 63.13; H,
2
2
2
2
+
9
17
2
1
H NMR spectra were recorded on a 400 MHz Varian-
10.01; N, 8.18. Found: C, 63.10; H, 9.92; N, 8.24.
3-(1-Piperidinyl)-propionic acid ethyl ester- (B) [6l].
Mercury Plus spectrometer and are reported as parts per million
ppm) downfield from a tetramethylsilane internal standard. The
1
1
(
Colorless oil; IR (KBr): 2937, 2848, 1737, 1173 cm ; H NMR

1
872
S. S. Pawar, D. V. Dekhane, M. S. Shingare, S. N. Thore
Vol 45
+
(
CDCl , 400 MHz, ꢀ, ppm): 4.07 (q, 2H, J=7.10 Hz, -OCH ),
(CH -C=O), 13.9 (-CH ); MS (EI, 70 eV): m/z = 146 [M+H] ;
3
2
2
3
2
.62 (t, 2H, J=7.72 Hz, N-CH ), 2.43 (t, 2H, J=7.72 Hz, -CH -
Anal. Calcd for C H NO : C, 57.90; H, 10.41; N, 9.65. Found:
2
2
7 15 2
C=O), 2.36 (m, 4H, N-CH ), 1.51 (m, 4H, CH ), 1.39 (m, 2H,
C, 58.04; H, 10.69; N, 9.71.
2
2
CH ), 1.24 (t, 3H, J=7.10 Hz, -CH ); MS (EI, 70 eV): m/z = 186
4-Dimethylamino-butan-2-one (K) [8a]. Colorless oil; IR
2
3
+
-1
1
[
M+H] ; Anal. Calcd for C H NO : C, 64.83; H, 10.34; N,
(KBr): 2955, 1741, 1198 cm ; H NMR (CDCl , 400 MHz, ꢀ,
10
19
2
3
7
.56. Found: C, 64.68; H, 10.12; N, 7.28.
-Piperidin-1-yl-butan-2-one (C) [6l]. Colorless oil; IR
ppm): 2.72 (t, 2H, J=7.30 Hz, N-CH ), 2.64 (t, 2H, J=7.30 Hz, -
2
4
CH -C=O), 2.52 (s, 6H, N-CH ), 2.06 (s, 3H, O-CCH ); MS (EI,
2
3
3
-1
1
+
(KBr): 2936, 1715, 1168 cm ; H NMR (CDCl , 400 MHz, ꢀ,
70 eV): m/z = 116 [M+H] .
3
ppm): 2.66 (t, 2H, N-CH ), 2.45 (t, 2H, -CH -C=O), 2.37 (m,
3-Dimethylamino-propionitrile (L). Colorless oil; IR (KBr):
2
2
-1
1
4
2
H, N-CH ), 2.14 (s, 3H, O=CCH ), 1.64 (m, 4H, CH ), 1.45 (m,
2968, 2246, 1741, 1202 cm ; H NMR (CDCl , 400 MHz, ꢀ,
2
3
2
3
+
H, -CH ); MS (EI, 70 eV): m/z = 156 [M+H] ; Anal. Calcd for
ppm): 2.68 (t, 2H, J=7.32 Hz, N-CH ), 2.62 (t, 2H, J=7.32 Hz, -
2
2
1
3
C H NO: C, 69.63; H, 11.04; N, 9.02. Found: C, 69.81; H,
CH -C=O), 2.52 (s, 6H, N-CH ); C NMR (CDCl , 100 MHz, ꢀ,
2 3 3
9
17
1
1.18; N, 9.28.
-(1-Piperidinyl)-propionitrile (D) [6l]. Colorless oil; IR
ppm): 114.2 (-CN), 57.1 (N-CH ), 44.2 (N-CH ), 1682 (CH );
2 3 2
+
3
MS (EI, 70 eV): m/z = 99 [M+H] ; Anal. Calcd for C H N : C,
5 10 2
-1
1
(KBr): 2939, 2247, 1673, 1116 cm ; H NMR (CDCl , 400
61.19; H, 10.27; N, 28.54. Found: C, 61.04; H, 10.39; N, 28.71.
3
MHz, ꢀ, ppm): 2.69 (t, 2H, J=7.18 Hz, N-CH ), 2.49 (t, 2H,
3-Diethylamino-propionic acid methyl ester (M) [6l].
Colorless oil; IR (KBr): 2961, 1739, 1212 cm ; H NMR
2
-1
1
J=7.18 Hz, CH -CN), 2.39 (m, 4H, N-CH ), 1.58 (m, 4H, CH ),
2
2
2
+
1
.43 (m, 4H, CH ); MS (EI, 70 eV): m/z = 139 [M+H] ; Anal.
(CDCl , 400 MHz, ꢀ, ppm): 3.75 (s, 3H, -OCH ), 2.90 (t, 2H,
2
3
3
Calcd for C H N : C, 69.52; H, 10.21; N, 20.27. Found: C,
J=7.35 Hz, N-CH ), 2.59 (q, 4H, J=7.22 Hz, N-CH ), 2.51 (t,
2 2
8
14
2
1
3
6
9.71; H, 10.18; N, 20.48.
-(1-Morpholinyl)-propionic acid methyl ester (E).
2H, J=7.35 Hz, CH C=O), 1.03 (t, 6H, J=7.22 Hz, CH );
C
2
3
3
NMR (CDCl , 100 MHz, ꢀ, ppm): 173.0 (-O-C=O), 54.1 (N-
3
-1
1
Colorless oil; IR (KBr): 2951, 1741, 1111 cm ; H NMR
CH ), 51.2 (-OCH ), 47.6 (-CH -N), 33.9 (CH -C=O), 13.1 (-
2
3
2
2
+
(
CDCl , 400 MHz, ꢀ, ppm): 3.67-3.69 (m, 7H, -OCH CH -O),
CH ); MS (EI, 70 eV): m/z = 160 [M+H] ; Anal. Calcd for
3
3,
2
3
2
.61 (t, 2H, J=7.20 Hz, N-CH ), 2.42 (t, 2H, J=7.20 Hz, -CH -
C H NO : C, 60.35; H, 10.76; N, 8.80. Found: C, 60.40; H,
10.89; N, 8.71.
2
1
2
8
17
2
3
C=O), 2.39 (m, 4H, N-CH ); C NMR (CDCl , 100 MHz, ꢀ,
2
3
ppm): 173.0 (-O-C=O), 68.8 (CH -O), 53.8 (-OCH ), 53.2 (N-
3-Diethylamino-propionic acid ethyl ester (N) [6n].
Colorless oil; IR (KBr): 2961, 1740, 1202 cm ; H NMR
2
3
-1
1
CH ), 51.5 (N-CH ), 33.1 (CH -C=O); MS (EI, 70 eV): m/z =
2
2
2
+
1
8
74 [M+H] ; Anal. Calcd for C H NO : C, 55.14; H, 8.73; N,
(CDCl , 400 MHz, ꢀ, ppm): 4.99 (q, 2H, -OCH ), 2.82 (t, 2H,
8
15
3
3
2
.09. Found: C, 55.37; H, 8.71; N, 8.20.
-(1-Morpholinyl)-propionic acid ethyl ester (F) [6p]
J=7.35 Hz, N-CH ), 2.52 (q, 4H, J=7.22 Hz, N-CH ), 2.49 (t,
2 2
3
2H, J=7.35 Hz, CH C=O), 1.03-1.12 (t, 9H, J=7.22 Hz, CH );
2 3
-1
1
+
Colorless oil; IR (KBr): 2953, 1739, 1117 cm ; H NMR
MS (EI, 70 eV): m/z = 174 [M+H] .
4-Diethylamino-butan-2-one (O) [6l]. Colorless oil; IR
(
CDCl , 400 MHz, ꢀ, ppm): 4.07 (q, 2H, J= 7.10 Hz, -OCH ),
3
2
-1
1
3
2
.69 (m, 4H, CH -O), 2.64 (t, 2H, J=7.20 Hz, N-CH ), 2.47 (t,
(KBr): 2968, 1741, 1202 cm ; H NMR (CDCl , 400 MHz, ꢀ,
2
2
3
H, J=7.20 Hz, -CH -C=O), 2.42 (m, 4H, N-CH ), 1.18 (t, 3H,
ppm): 2.72 (t, 2H, J=7.32 Hz, N-CH ), 2.64 (t, 2H, J=7.32 Hz, -
2
2
2
+
J= 7.10 Hz, -CH ); MS (EI, 70 eV): m/z = 188 [M+H] ; Anal.
CH -C=O), 2.52 (q, 4H, J=7.22 Hz, N-CH ), 2.06 (s, 3H,
3
2
2
Calcd for C H NO : C, 57.73; H, 9.15; N, 7.48. Found: C,
O=CCH ), 1.06 (t, 6H, J= 7.22 Hz, CH ); MS (EI, 70 eV): m/z =
3 3
9
17
3
+
5
7.55; H, 9.05; N, 7.59.
-Morpholin-4-yl-butan-2-one (G) [6o]. Colorless oil; IR
144 [M+H] .
3-Diethylamino-propionitrile (P) [6l]. Colorless oil; IR
4
-1
1
-1
1
(KBr): 2951, 1172, 1111 cm ; H NMR (CDCl , 400 MHz, ꢀ,
(KBr): 2971, 2256, 1741, 1209 cm ; H NMR (CDCl , 400
3
3
ppm): 3.67 (t, 4H, CH -O), 2.64 (t, 2H, J=6.28 Hz, N-CH ), 2.53
MHz, ꢀ, ppm): 2.76 (t, 2H, J=7.32 Hz, N-CH ), 2.59 (t, 2H,
2
2
2
(
3
t, 2H, J=6.28 Hz, -CH -C=O), 2.39 (m, 4H, N-CH ), 2.12 (s,
J=7.32 Hz, -CH -C=O), 2.54 (q, 4H, J=7.18 Hz, N-CH ), 1.06 (t,
2
2
2
2
+
+
H, O=CCH ); MS (EI, 70 eV): m/z = 158 [M+H] .
6H, J=7.18 Hz, CH ); MS (EI, 70 ev): m/z = 127 [M+H] .
3
3
3
-(1-morpholinyl)-propionitrile (H) [6p]. Colorless oil; IR
Acknowledgment. The authors are thankful Vinyakrao Patil
Mahavidyala Vaijapur-423 701 (M.S.), India for partial support
of this work.
-1 1
(
ꢀ
KBr): 2954, 2238, 1671, 1106 cm ; H NMR (CDCl , 400 MHz,
, ppm): 3.69 (t, 4H, CH -O), 2.65 (t, 2H, N-CH ), 2.54 (t, 2H,
3
2
2
CH -CN), 2.48-2.52 (m, 4H, N-CH ); MS (EI, 70 eV): m/z =
2
2
+
1
1
41 [M+H] ; Anal. Calcd for C H N O: C, 59.98; H, 8.63; N,
7 12 2
9.98. Found: C, 59.65; H, 8.45; N, 19.79.
-Dimethylamino-propionic acid methyl ester (I). Faint
REFERENCES AND NOTES
3
-1
1
yellow oil; IR (KBr): 2968, 1741, 1202 cm ; H NMR (CDCl ,
00 MHz, ꢀ, ppm): 3.68 (s, 3H, -OCH ), 2.80 (t, 2H, J=7.22 Hz,
N-CH ), 2.46 (t, 2H, J=7.22 Hz, -CH -C=O), 2.52 (s, 6H, N-
3
*
Address correspondence to this author at the Department of
4
Chemistry, Vinyakrao Patil Mahavidyala Vaijapur, Aurangabad- 423
701(M.S.) India; Phone: +91(2436) 222086; Fax: +91(2436) 224581;
Email: snthore@rediffmail.com
3
2
1
2
3
CH ); C NMR (CDCl , 100 MHz, ꢀ, ppm): 173.0 (-O-C=O),
3
3
5
5.1 (N-CH ), 50.9 (-OCH ), 45.6 (N-CH ), 33.2 (CH -C=O).
[1] (a) Perlmutter, P. In conjugate Addition Reaction in Organic
Synthesis; Pergamon Press; Oxford, 1992. (b) Lee, V. J. In
Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I. Eds.;
Pergamon Press: New York, 1991, Vol. 4, Chapter1.2, pp 69.
2
3
2
2
+
MS (EI, 70 eV): m/z = 132 [M+H] ;Anal. Calcd for
C H NO : C, 54.94; H, 9.99; N, 10.68. Found: C, 54.81; H,
9
6
13
2
.90; N, 10.62.
-Dimethylamino-propionic acid ethyl ester (J).Colorless
[2] (a) Bull, S. D.; Davies, S.G.; Delgado-Ballester, S.; Fenton,
3
G.; Kelly, P. M.; Simth, A. D. Synlett. 2000, 1257. (b) Christoffers, J.
Eur. J. Org. Chem. 1998, 1259. (c) Giuseppone, N.; Vander Weghe, P.;
Fellah. M.; Collin, J. Tetrahedron 1998, 54, 13129. (d) Hagiwara, H.;
Okamoto, T.; Harada, N.; Uda, H. Tetrahedron 1995, 51, 9891.
[3] (a) Enders, D.; Wahl, H.; Bettary, W. Angew. Chem., Int. Ed.
Engl. 1995, 34, 527. (b) Simpkins, N. S. Tetrahedron 1990, 46, 6851. (c)
-1
1
oil; IR (KBr): 2967, 1741, 1202 cm ; H NMR (CDCl , 400
MHz, ꢀ, ppm): 3.97 (q, 2H, -OCH ), 2.80 (t, 2H, J=7.26 Hz, N-
CH ), 2.46 (t, 2H, J=7.26 Hz, -CH -C=O), 2.32 (s, 6H, N-CH ),
1
3
2
2
2
3
1
3
.30 (t, 3H, CH ); C NMR (CDCl , 100 MHz, ꢀ, ppm): 173.0
3
3
(-O-C=O), 55.1 (N-CH ), 50.9 (-OCH ), 45.6 (N-CH ), 33.2
2
3
3

Nov-Dec 2008
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3
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