Vol. 38
C. G. Dave and K. J. Patel
460
Table 4
1
IR and H NMR Spectral Data for Compounds 6a-t
-1
1
No.
6a
ir(potassium bromide) cm
1685, 1595, 1550, 855
1695, 1590, 1535, 1490
1687, 1593, 1565, 1490
1686, 1593, 1551, 1494
H nmr (δ ppm)
2.57 (s, 3H, CH ), 6.94 (s, 1H, Ar-H at C )
3
6
7.21-7.50 (m, 5H, Ar-H)
6b
6c
1.29-1.34 (t, J = 7.5, 3H, CH ), 3.24-3.31 (q, J = 7.5, 2H, CH ), 6.97(s, 1H, Ar-H at
3
2
C ) 7.28-7.58 (m, 5H, Ar-H)
6
0.94-0.98 (t, J = 7.4, 3H, CH ), 1.60-1.72 (sextet, J = 7.5, 2H, CH ), 3.20-3.26 (t,
3
2
J = 7.5, 2H, CH ), 7.0 (s, 1H, Ar-H at C ), 7.25-7.52 (m, 5H, Ar-H)
2
6
6d
0.86-0.90 (t, J = 7.5, 3H, CH ), 1.37-1.47 (sextet, J = 7.3, 2H, CH ), 1.59-1.70
3
2
(quintet, J = 7.1, 2H, CH ), 3.25-3.32 (t, J = 7.5, 2H, CH ), 6.98 (s, 1H, Ar-H at
2
2
C ), 7.22-7.42 (m, 5H, Ar-H)
6
6e
6f
1685, 1597, 1545, 1495
1675, 1592, 1546, 856
1689, 1590, 1555, 1505
1689, 1593, 1548, 1504
1690, 1590, 1535, 1490
4.57 (s, 2H, CH ), 6.95 (s, 1H, Ar-H at C )
7.20-7.68 (m, 10H, Ar-H)
2
6
2.60 (s, 3H, CH ), 7.01 (s, 1H, Ar-H at C ),
3
6
7.12-7.26 (m, 4H, Ar-H)
6g
6h
6i
1.26-1.33 (t, J = 7.3, 3H, CH ), 3.25-3.33 (q, J = 7.2, 2H, CH ), 6.99 (s, 1H, Ar-H
3
2
at C ), 7.14-7.28 (m, 4H, Ar-H)
6
0.92-0.97 (t, J = 7.6, 3H, CH ), 1.58-1.69 (sextet, J = 7.2, 2H, CH ), 3.19-3.25(t,
3
2
J = 7.5, 2H, CH ), 6.93 (s, 1H, Ar-H at C ), 7.17-7.25 (m, 4H, Ar-H)
2
6
0.88-0.93 (t, J = 7.4, 3H, CH ), 1.38-1.49 (sextet, J = 7.3, 2H, CH ), 1.61-1.71
3
2
(quintet, J = 7.1, 2H, CH ), 3.29-3.35 (t, J = 7.5, 2H, CH ), 6.97 (s, 1H, Ar-H at
2
2
C ), 7.15-7.29 (m, 4H, Ar-H)
6
6j
1682, 1596, 1547, 1507
4.59 (s, 2H, CH ), 6.98 (s, 1H, Ar-H at C )
2
6
7.16-7.62 (m, 9H, Ar-H)
6k
6l
1680, 1593, 1545, 854
1686, 1594, 1548, 1490
2.59 (s, 3H, CH ), 7.0 (s, 1H, Ar-H, at C ), 7.19-7.51 (m, 4H, Ar-H)
3
6
1.25-1.32 (t, J = 7.2, 3H, CH ), 3.24-3.32 (q, J = 7.5, 2H, CH ), 6.96 (s, 1H, Ar-H,
3
2
at C ), 7.20-7.53 (m, 4H, Ar-H)
6
6m
4n
1679, 1582, 1545, 1489
1687, 1593, 1548, 1490
0.97-1.02 (t, J = 7.5, 3H, CH ), 1.63-1.76 (sextet, J = 7.2, 2H, CH ), 3.26-3.31 (t,
3
2
J = 7.5, 2H, CH ), 6.99 (s, 1H, Ar-H at C ) 7.23-7.54 (m, 4H, Ar-H)
2
6
0.87-0.92 (t, J = 7.2, 3H, CH ), 1.37-1.48 (sextet, J = 7.3, 2H, CH ), 1.60-1.69
3
2
(quintet, J = 7.3, 2H, CH ), 3.28-3.33 (t, J = 7.2, 2H, CH ), 7.02 (s, 1H, Ar-H, at
2
2
C ), 7.22-7.53 (m, 4H, Ar-H)
6
4o
4p
4q
1687, 1594, 1547, 1490
1685, 1592, 1547, 858
1696, 1594, 1546, 1497
4.58 (s, 2H, CH ), 6.99 (s, 1H, Ar-H at C ), 7.27-7.65 (m, 9H, Ar-H)
2
6
2.61 (s, 3H, CH ), 6.97 (s, 1H, Ar-H at C ), 7.32-7.52 (m, 3H, Ar-H)
3
6
1.27-1.34 (t, J = 7.5, 3H, CH ), 3.26-3.34 (q, J = 7.2, 2H, CH ), 7.01 (s, 1H, Ar-H
3
2
at C ), 7.30-7.55 (m, 3H, Ar-H)
6
4r
4s
1689, 1594, 1547, 1498
1697, 1594, 1546, 1497
0.95-1.0 (t, J = 7.4, 3H, CH ), 1.62-1.75 (sextet, J = 7.3, 2H, CH ), 3.27-3.33 (t,
3
2
J = 7.1, 2H, CH ), 7.03 (s, 1H, Ar-H at C ), 7.28-7.53 (m, 3H, Ar-H)
2
6
0.89-0.95 (t, J = 7.4, 3H, CH ), 1.38-1.50 (sextet, J = 7.3, 2H, CH ), 1.62-1.70
3
2
(quintet, J = 7.5, 2H, CH ), 3.30-3.34 (t, J = 7.5, 2H, CH ), 6.98 (s, 1H, Ar-H at
2
2
C ), 7.29-7.44 (m, 3H, Ar-H)
6
4t
1690, 1595, 1550, 1495
Table 5
4.60 (s, 2H, CH ), 7.0 (s, 1H, Ar-H at C ), 7.35-7.70 (m, 8H, Ar-H)
2
6
isolated by filtration, washed with water, dried and crystallized
from glacial acetic acid.
13
C NMR data of 6l & 6h (δ value in DMSO-d , TMS as Internal Standard)
6
Method B.
6l
6h
C-2
C-4
C-4a
C-5
C-6
164.53
161.47
111.01
131.00
123.80
157.65
160.28
21.74
24.45
151.36
134.86
131.54
129.64
26.52
13.86
-
164.95
161.81
117.66
131.63
124.32
158.33
161.60
21.45
22.32
152.65
162.49
131.15
131.04
34.74
25.16
12.5
A mixture of 2-amino-3-carbethoxy-4,6-dimethylpyridine 1
(0.01 mole, 1.94 g), the appropriate isothiocyanate 4 (0.01 mole)
and pyridine (10 ml) was refluxed in an oil bath for 12-14 hours.
The reaction mixture was cooled, poured onto crushed ice and
the precipitated solid was isolated by filtration, washed repeat-
edly with water followed by sodium bicarbonate solution (5%
w/v) and finally with water. The dried crude product was crys-
tallised from glacial acetic acid to give 3.
C-7
C-8a
C-5a
C-7a
C-3a
C-3d
C-3b,3f
C-3c,3e
C-2a
C-2b
C-2c
General Procedure for the Synthesis of 3-Substituted
2-Alkylthio-5,7-dimethylpyrido[2,3-d]pyrimidin-4(3H)-ones 6a-t.
To a vigorously stirred mixture of 3-substituted 2-thioxo-5,7-
dimethylpyrido[2,3-d]pyrimidin-4(3H)-one 3 (0.01 mole), tetra-
n-butylammonium bromide (TBAB) (0.001 mole), aqueous 50%