2
224
S. Chitra, K. Pandiarajan / Tetrahedron Letters 50 (2009) 2222–2224
0
further purified by recrystallization from hot ethanol to afford pure
dihydropyrimidin-2(1H)-ones. The catalyst could be reused in the next run.
All the products were characterized by elemental analyses, IR, 1H NMR and 13
NMR spectra. For compounds 4a, 4j, 4k, 4m, and 4n the observed spectral data
147.0 (C-1 ), 128.2 and 123.8 (other aromatic carbons), 99.0 (C-5), 67.0 (CH of
iPr), 54.2 (C-4), 22.0 and 21.8 (CH
C H N O
15 17 3 5
Compound 4h: IR (KBr) cm = 3247 and 3120 (N–H str.), 1705 and 1647 (C@O
str.); 1H NMR (DMSO-d
) d = 9.00 (s, 1H, H-1), 7.45 (s, 1H, H-3), 7.32–6.96 (m,
4H, Ar-H), 5.25 (br s, 1H, H-4), 4.88 (m, 1H, CH of iPr), 1.19 and 1.02 (d, 3H,
3 3
of iPr), 18.2 (CH at C-6). Anal. Calcd for
C
: C, 56.42; H, 5.32; N, 13.16. Found: C, 56.50; H, 5.33; N, 13.15.
ꢁ
1
1
9
were in excellent agreement with those reported. Only for the newly
synthesized compounds the spectral and analytical data are given below.
6
ꢁ
1
13
Compound 4b: IR (KBr) cm = 3246 and 3119 (N–H str.), 1706 and 1651 (C@O
str.); 1H NMR (DMSO-d
) d = 9.11 (s, 1H, H-1), 7.67 (s, 1H, H-3), 7.32–7.21 (m,
H, Ar-H), 5.11 (d, 1H, J = 4 Hz, H-4), 4.79 (m, 1H, CH of iPr), 1.14 and 0.96 (d,
J = 4 Hz, CH
3
of iPr), 2.31 (s, 3H, CH
3
at C-6); C NMR (DMSO-d
6
) d = 164.7 (CO
0
0
6
of the ester), 162.7 (C-4 ), 152.2 (C-6), 147.5 (C-2), 140.7 (C-1 ), 128.0 and 114.4
(other aromatic carbons), 99.6 (C-5), 66.2 (CH of iPr), 53.7 (C-4), 21.6 and 21.2
of iPr), 17.7 (CH at C-6). Anal. Calcd for C15H N O F: C, 61.64; H, 5.82; N,
3 3 17 2 3
9.58. Found: C, 61.55; H, 5.83; N, 9.55.
Compound 4i: IR (KBr) cm = 3238 and 3134 (N–H str.), 1703 (C@O str.),
1593 (C@S str.); 1H NMR (DMSO-d
) d = 9.92 (s, 1H, H-1), 9.34 (s, 1H, H-3),
7.35–7.25 (m, 5H, Ar-H), 5.29 (d, 1H, J = 4 Hz, H-4), 4.92 (m, 1H, CH of iPr),
1.21 and 1.04 (d, 3H, J = 4 Hz, CH of iPr), 2.36 (s, 3H, CH
at C-6); 13C NMR
) d = 174.0 (C@S), 164.6 (CO of the ester), 144.1 (C-6), 143.3 (C-
5
3
1
3
H, J = 4 Hz, CH
3
of iPr), 2.23 (s, 3H, CH
3
at C-6); C NMR (DMSO-d
6
) d = 164.7
(CH
0
(
(
(
1
6
CO of the ester), 152.0 (C-6), 148.0 (C-2), 144.9 (C-1 ), 128.2, 127.1 and 126.2
other aromatic carbons), 99.4 (C-5), 66.2 (CH of iPr), 54.0 (C-4), 21.7 and 21.3
ꢁ
1
+
CH
3
of iPr), 17.6 (CH
87 (38). Anal. Calcd for C15
5.80; H, 6.58; N, 10.25.
3
at C-6); MS (m/z, %) 275 [(M+1) , 100], 231 (65), 197 (48),
6
18 2 3
H N O : C, 65.69; H, 6.56; N, 10.21. Found: C,
3
3
ꢁ
1
Compound 4c: IR (KBr) cm = 3248 and 3120 (N–H str.), 1722 and 1648 (C@O
str.); 1H NMR (DMSO-d
) d = 9.10 (s, 1H, H-1), 7.61 (s, 1H, H-3), 7.33–7.26 (m,
H, Ar-H), 5.20 (d, 1H, J = 4 Hz, H-4), 4.86 (m, 1H, CH of iPr), 1.18 and 1.02 (d,
(DMSO-d
6
0
6
1 ), 127.8, 127.2 and 126.4 (other aromatic carbons), 101.3 (C-5), 66.7 (CH
of iPr), 54.6 (C-4), 21.5 and 21.1 (CH
4
3
3
of iPr), 17.1 (CH
3
at C-6). Anal. Calcd
1
3
H, J = 4 Hz, CH
3
of iPr), 2.28 (s, 3H, CH
3
at C-6); C NMR (DMSO-d
6
) d = 164.6
for C15
9.64.
18 2 2
H N O S: C, 62.06; H, 6.20; N, 9.65. Found: C, 62.19; H, 6.18; N,
0
0
(
CO of the ester), 152.2 (C-6), 147.9 (C-2), 143.5 (C-1 ), 132.0 (C-4 ), 127.9 and
ꢁ
1
1
2
5
27.8 (other aromatic carbons), 99.2 (C-5), 66.2 (CH of iPr), 53.7 (C-4), 21.6 and
1.3 (CH of iPr), 17.7 (CH at C-6). Anal. Calcd for C15 Cl: C, 58.35; H,
.51; N, 9.07. Found: C, 58.48; H, 5.49; N, 9.05.
Compound 4l: IR (KBr) cm = 3229 and 3120 (N–H str.), 1701 and 1619
(C@O str.); 1H NMR (DMSO-d
) d = 9.14 (s, 1H, H-1), 7.77 (s, 1H, H-3), 7.11
(s, 4H, Ar-H), 5.19 (d, 1H, J = 4 Hz, H-4), 2.26 (s, 3H, CH
at C-4 ), 2.06 (s, 3H, CH
152.1 (C-6), 147.8 (C-2), 141.3 (C-1 ), 136.4 (C-4 ), 129.0 and 126.3 (other
aromatic carbons), 109.5 (C-5), 53.5 (C-4), 30.1 (CH
18.8 (CH at C-6). Anal. Calcd for C14
Found: C, 69.00; H, 6.53; N, 11.43.
Compound 4o: IR (KBr) cm = 3257 and 3153 (N–H str.), 1708 and 1675
(C@O str.); 1
NMR (DMSO-d d = 9.11 (s, 1H, H-1), 7.64 (s, 1H, H-3),
7.28–7.33 (m, 4H, Ar-H), 5.35 (d, 1H, J = 4Hz, H-4), 2.23 (s, 3H, CH at C-6),
3
3
H
N
17 2
O
3
6
3
at C-6), 2.24 (s,
) d = 194.3 (CO),
ꢁ
1
0
13
Compound 4d: IR (KBr) cm = 3246 and 3118 (N–H str.), 1709 and 1649 (C@O
str.); 1H NMR (DMSO-d
) d = 9.14 (s, 1H, H-1), 7.87 (s, 1H, H-3), 7.34–7.17 (m,
H, Ar-H), 5.75 (br s, 1H, H-4), 4.81 (m, 1H, CH of iPr), 1.15 and 0.83 (d, 3H,
3H, CH
3
3
CO); C NMR (DMSO-d
6
0
0
6
0
4
3
CO), 20.6 (CH
3
at C-4 ),
1
3
J = 4 Hz, CH
3
of iPr), 2.36 (s, 3H, CH
3
at C-6); C NMR (DMSO-d
6
) d = 164.9 (CO
3
16 2 2
H N O : C, 68.85; H, 6.55; N, 11.47.
0
0
of the ester), 152.2 (C-6), 149.0 (C-2), 141.6 (C-1 ), 132.3 (C-4 ), 129.4, 128.9,
ꢁ
1
1
4
5
28.8 and 127.5 (other aromatic carbons), 98.6 (C-5), 66.5 (CH of iPr), 51.9 (C-
), 21.9 and 21.4 (CH of iPr), 18.0 (CH at C-6). Anal. Calcd for C15 Cl: C,
8.35; H, 5.51; N, 9.07. Found: C, 58.36; H, 5.52; N, 9.04.
3
3
H
17
2
N O
3
H
6
)
3
ꢁ
1
13
0
Compound 4e: IR (KBr) cm = 3243 and 3117 (N–H str.), 1706 and 1647 (C@O
str.); 1H NMR (DMSO-d
) d = 9.03 (s, 1H, H-1), 7.54 (s, 1H, H-3), 7.17–7.06 (m,
H, Ar-H), 5.17 (d, 1H, J = 4 Hz, H-4), 4.84 (m, 1H, CH of iPr), 1.18 and 1.02 (d,
2.11 (s, 3H, CH
3
CO); C NMR (DMSO-d
6
) d = 194.7 (CO), 161.5 (C-4 ), 152.5
0
6
(C-6), 147.8 (C-2), 139.6 (C-1 ), 128.2 and 115 (other aromatic carbons),
109.5 (C-5), 53.5 (C-4), 30.0 (CH CO), 19.0 (CH at C-6). Anal. Calcd for
3 3
4
3
0
13
H, J = 4 Hz, CH
3
of iPr), 2.28 (s, 3H, CH
3
at C-6), 2.27 (s, 3H, CH
3
at C-4 );
C
C
13
H
13
N
2
O
2
F: C, 62.90; H, 5.24; N, 11.29. Found: C, 62.85; H, 5.23; N,
NMR (DMSO-d
6
) d = 164.8 (CO of the ester), 152.4 (C-6), 147.2 (C-2), 141.8 (C-
11.26.
0
0
ꢁ1
1
), 136.1 (C-4 ), 128.4 and 126.1 (other aromatic carbons), 99.9 (C-5), 66.1 (CH
Compound 4p: IR (KBr) cm = 3251 and 3120 (N–H str.), 1727 and 1623
0
(C@O str.); 1H NMR (DMSO-d
of iPr), 53.9 (C-4), 21.6 and 21.3 (CH
3
of iPr), 20.6 (CH
3
at C-4 ), 17.7 (CH
3
at C-
6
) d = 9.38 (s, 1H, H-1), 8.00 (s, 1H, H-3), 8.15
6
6
). Anal. Calcd for C16
.93; N, 9.70.
H
20
N
2
O
3
: C, 66.66; H, 6.94; N, 9.72. Found: C, 66.60; H,
(d, 2H, J = 8 Hz, Ar-H), 7.54 (d, 2H, J = 8 Hz, Ar-H), 5.45 (d, 1H, J = 4Hz, H-4),
2.35 (s, 3H, CH
3
at C-6), 2.20 (s, 3H, CH
3
CO); 13C NMR (DMSO-d
6
) d = 194.2
ꢁ
1
0
0
Compound 4f: IR (KBr) cm = 3243 and 3114 (N–H str.), 1702 and 1649 (C@O
str.); 1H NMR (DMSO-d
) d = 8.93 (s, 1H, H-1), 7.83 (s, 1H, H-3), 7.34–6.79 (m,
H, Ar-H), 5.21 (br s, 1H, H-4), 4.88 (m, 1H, CH of iPr), 1.19 and 1.03 (d, 3H,
(CO), 152.6 (C-4 ), 151.7 (C-6), 149.3 (C-2), 147 (C-1 ), 128.0 and 123.9
6
(other aromatic carbons), 109.8 (C-5), 53.7 (C-4), 30.9 (CH
3
CO), 19.5 (CH
3
at
4
C-6). Anal. Calcd for C13
H
13
N
3
O
4
: C, 56.72; H, 4.72; N, 15.27. Found: C,
0
13
J = 4 Hz, CH
3
of iPr), 2.29 (s, 3H, CH
3
at C-6), 3.76 (s, 3H, OCH
3
at C-4 ); C NMR
56.80; H, 4.73; N, 15.31.
Compound 4q: IR (KBr) cm = 3267 and 3108 (N–H str.), 1699 and 1648
(C@O str.); 1H NMR (DMSO-d
) d = 9.18 (s, 1H, H-1), 8.95 (s, 1H, H-3), 7.41
0
ꢁ1
(
DMSO-d
6
) d = 164.8 (CO of the ester), 158.2 (C-4 ), 152.4 (C-6), 147.0 (C-2),
36.9 (C-1 ), 127.4 and 113.0 (other aromatic carbons), 100.1 (C-5), 66.1 (CH of
0
1
6
0
iPr), 54.7 (C-4), 53.8 (OCH
Anal. Calcd for C16
N, 9.24.
Compound 4g: IR (KBr) cm = 3246 and 3122 (N–H str.), 1703 and 1645 (C@O
str.); H NMR (DMSO-d
3
at C-4 ), 21.6 and 21.3 (CH
3
of iPr), 17.7 (CH
3
at C-6).
(d, 2H, J = 8 Hz, Ar-H), 7.01 (d, 2H, J = 8 Hz, Ar-H), 5.14 (d, 1H, J = 4Hz, H–4),
H
20
N
2
O
4
: C, 63.15; H, 6.57; N, 9.21. Found: C, 62.91; H, 6.59;
2.24 (s, 3H, CH
3
at C-6), 1.98 (s, 3H, CH
3
CO); 13C NMR (DMSO-d
6
) d = 195.8
0
0
(CO), 157.4 (C-4 ), 153.2 (C-6), 148.1 (C-2), 135.1 (C-1 ), 128.4, 116.0 (other
ꢁ
1
aromatic carbons), 110.2 (C-5), 55.0 (C-4), 30.6 (CH
3
CO) 19.7 (CH
3
at C-6).
1
6
) d = 9.27 (s, 1H, H-1), 8.19 (d, 2H, J = 8 Hz, Ar-H), 7.86
Anal. Calcd for C13
5.68; N, 11.35.
14 2 3
H N O : C, 63.41; H, 5.69; N, 11.38. Found: C, 63.50; H,
(
s, 1H, H-3), 7.46 (d, 2H, J = 8 Hz, Ar-H), 5.36 (br s, 1H, H-4), 4.87 (m, 1H, CH of
iPr), 1.20 and 1.03 (d, 3H, J = 4 Hz, CH
DMSO-d
3
of iPr), 2.33 (s, 3H, CH
3
at C-6); 13C NMR
19. Wang, M.; Song, Z.; Gong, H.; Jiang, H. Prep. Biochem. Biotechnol. 2008, 38, 105–
0
(
6
) d = 164.9 (CO of the ester), 152.5 (C-4 ), 152.2 (C-6); 149.3 (C-2),
114.