M. Rana et al.
Bioorganic Chemistry 108 (2021) 104665
fused CaCl2 and recrystallized in chloroform affording pyrazoline de-
rivatives (3a–3l). The synthesis of pyrazoline derivatives is shown in
Scheme 1.
2.2.6. 3-(2-chlorophenyl)-5-(4-(dimethylamino)phenyl)-4,5-dihydro-1H-
pyrazole-1-carbaldehyde (3f)
Yellow, Yield 70%. Mp: 195 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O) 1579,
–
–
–
ν
(C N) 1477. (CDCl , 300 MHz ppm): 7.78–7.90 (d, 2H), 7.66–7.69 (d,
–
3
2.2.1. 5-(4-(dimethylamino)phenyl)-3-(4-methoxyphenyl)-4,5-dihydro-
2H), 7.11–7.26(m, 3H), 6.65–6.69 (d, 2H), 8.93 (s, 1H), 5.48 (dd, J = 4.5
and 17.7 Hz, 1H), 3.73 (dd, J = 11.5 and 17.7 Hz, 1H), 3.19 (dd, J = 4.5
and 11.7 Hz, 1H), 2.94 (s, 6H).13C NMR (CDCl3, 75.47 MHz): 160.07,
154.70, 150.30, 136.49, 129.66, 129.08, 128.09, 127.90, 126.72,
112.70, 58.88, 42.39, 40.53.MS (m/z): 328.23(M + 1), Calculated %:
1H-pyrazole-1-carbaldehyde (3a)
Light green, Yield 80%. Mp: 130 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
–
–
1611,
ν
(C N) 1562. 1H NMR (CDCl3, 300 MHz ppm): 7.67–7.69 (d,
–
–
2H), 7.11–7.26 (d, 2H), 6.93–6.95 (d, 2H), 6.66–6.69 (d, 2H), 8.91 (s,
1H), 5.43 (dd, J = 4.6 and 17.8 Hz, 1H), 3.72 (dd, J = 11.8 and 17.7 Hz,
C
18H18ClN3O: C 65.95; H 5.53; N 12.82. Found, %: C 65.94; H 5.55; N
1H), 3.19 (dd, J = 4.6 and 11.8 Hz, 1H), 2.95 (s, 6H), 3.85 (s, 3H).13
C
12.80.
NMR (CDCl3, 75.47 MHz): 161.48, 159.89, 155.64, 150.26, 129.02,
128.51, 128.29, 126.75, 123.79, 144.21, 112.75, 58.56, 55.43, 42.58,
40.55.MS (m/z): 324.20 (M + 1), Calculated %: C19H21N3O2: C 70.57; H
6.55; N 12.99. Found, %: C 70.56; H 6.57; N 12.95.
2.2.7. 5-(4-(dimethylamino)phenyl)-3-(p-tolyl)-4,5-dihydro-1H-pyrazole-
1-carbaldehyde (3g)
Light green, Yield 72%. Mp: 140 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
–
–
1
–
1588,
ν
(C N) 1460. H NMR (300 MHz, CDCl ) δ 7.62–7.65 (d, 2H),
–
3
2.2.2. 3-(4-chlorophenyl)-5-(4-(dimethylamino)phenyl)-4,5-dihydro-1H-
7.22–7.26 (d, 2H), 7.12–7.14 (d, 2H), 6.66–6.68 (d, 2H), 8.92 (s, 1H),
5.45 (dd, J = 17.6, 4.6 Hz, 1H), 3.74 (dd, J = 17.8, 11.7 Hz, 1H), 3.21
(dd, J = 11.8, 4.8 Hz, 1H), 2.93 (s, 6H), 2.40 (s, 3H). 13C NMR (CDCl3,
75.47 MHz): 160.01, 155.98, 150.26, 140.91, 129.51, 128.46, 128.37,
130.00, 126.76, 126.64, 112.74, 58.61, 42.53, 40.55, 21.53.MS (m/z):
308.21 (M + 1) Calculated %: C19H21N3O: C 74.24; H 6.89; N 13.67.
Found, %: C 74.29; H 6.92; N 13.68.
pyrazole-1-carbaldehyde (3b)
Green, Yield 75%. Mp: 180 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O) 1615,
–
–
–
ν
(C N) 1523. (CDCl , 300 MHz ppm): 7.66–7.69 (d, 2H), 7.39–7.42 (d,
–
3
2H), 7.11– 7.26(d, 2H), 6.66–6.69(d, 2H), 8.92 (s, 1H),5.46 (dd, J = 4.5
and 11.6 Hz, 1H), 3.71 (dd, J = 11.8 and 17.7 Hz, 1H), 3.18 (dd, J = 5.1
and 17.7 Hz, 1H), 2.90 (s, 6H).13C NMR (CDCl3, 75.47 MHz): 160.07,
154.69, 150.32, 136.49, 129.70, 129.08, 128.53, 128.11, 126.73,
112.72, 58.89, 42.38, 40.51.MS (m/z): 328.17 (M + 1), Calculated %:
2.2.8. 5-(4-(dimethylamino)phenyl)-3-phenyl-4,5-dihydro-1H-pyrazole-1-
C
18H18ClN3O: C 65.95; H 5.53; N 12.82. Found, %: C 65.95; H 5.48; N
carbaldehyde (3h)
Light green, Yield 68%. Mp: 135 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
–
12.85.
–
1
–
1615,
ν
(C N) 1560. H NMR (300 MHz, CDCl ) δ 7.73–7.76 (d, 2H),
–
3
2.2.3. 5-(4-(dimethylamino)phenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-
7.43 – 7.45 (d, 2H), 7.12–7.15 (d, 2H), 6.66–6.69 (d, 2H), 8.94 (s, 1H),
5.47 (dd, J = 17.6, 4.6 Hz, 1H), 3.76 (dd, J = 17.8, 11.7 Hz, 1H), 3.23
(dd, J = 11.8, 4.8 Hz, 1H), 2.92 (s, 6H).13C NMR (CDCl3, 75.47 MHz):
160.10, 155.88, 150.29, 131.16, 130.52, 128.80, 128.55, 128.35,
126.76, 126.67, 112.74,58.72, 42.48, 42.54. MS (m/z): 294.18 (M + 1),
Calculated %: C18H19N3O: C 73.69; H 6.53; N 14.32. Found, %: C 73.70;
H 6.48; N 14.34.
pyrazole-1-carbaldehyde (3c)
Light green, Yield 82%. Mp: 148 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
–
–
1
–
–
1579,
ν
(C N) 1497. H NMR (300 MHz, CDCl ) δ 7.65–7.68 (d, 4H),
3
7.37–7.40 (d, 2H), 7.09–7.12 (d, 2H), 6.65–6.68, (d, 2H), 8.92 (s, 1H),
5.45 (dd, J = 17.8, 4.1 Hz, 1H), 3.71 (dd, J = 17.7, 11.7 Hz, 1H), 3.16
(dd, J = 11.7, 4.2 Hz, 1H), 2.93 (s, 6H). 13C NMR (75 MHz, CDCl3) δ
160.07, 154.69 150.31, 136.47, 129.70, 129.08, 128.54, 128.12,
127.91, 127.25, 126.73 112.71, 58.89, 42.38, 40.52.MS (m/z): 312.28
(M + 1), Calculated, %: C18H18FN3O: C 69.44; H 5.83; N 13.50. Found,
%: C 69.47; H 5.84; N 13.51.
2.2.9. 5-(4-(dimethylamino)phenyl)-3-(4-nitrophenyl)-4,5-dihydro-1H-
pyrazole-1-carbaldehyde (3i)
Yellow, Yield 86%. Mp: 175 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O) 1590,
–
–
–
ν
(C N) 1460. 1H NMR (300 MHz, CDCl3) δ 8.27–8.30 (d, 2H),
–
2.2.4. 3-(4-bromophenyl)-5-(4-(dimethylamino)phenyl)-4,5-dihydro-1H-
7.88–7.91 (d, 2H), 7.10–7.13 (d, 2H), 6.66–6.69 (d, 2H), 8.96 (s, 1H),
5.52 (dd, J = 17.8, J = 4.9 Hz, 1H), 3.79 (dd, J = 17.8, 11.6 Hz, 1H),
3.26 (dd, J = 11.7, 4.9 Hz, 1H), 2.95 (s, 6H).13C NMR (CDCl3, 75.47
MHz): 160.44, 159.49, 154.91, 150.38, 148.51, 137.49, 128.91, 128.26,
127.14, 124.45, 112.86, 59.27, 56.47, 42.42. MS (m/z): 339.19(M + 1),
Calculated %: C18H18N4O3: C 63.89; H 5.36; N 16.56. Found, %: C 63.85;
H 5.41; N 16.58.
pyrazole-1-carbaldehyde (3d)
White, Yield 75%. Mp: 170 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O) 1658,
–
–
1
–
–
ν
(C N) 1591. H NMR (CDCl , 300 MHz): 7.65–7.68 (d, 2H), 7.38–7.41
3
(d, 2H), 7.10– 7.13 (d, 2H), 5.45 (dd, J = 4.5 and 17.7 Hz, 1H), 3.71 (dd,
J = 11.8 and 17.7 Hz, 1H), 3.18 (dd, J = 4.5 and 11.8 Hz, 1H), 2.49 (s,
6H). 13C NMR (CDCl3, 75.47 MHz): 159.83, 151.46, 150.32, 134.65,
132.97, 132.00, 129.06, 128.96, 128.07, 127.70, 127.28, 126.75,
112.72, 58.81, 43.16, 40.53. MS (m/z): 372.13 (M + 1), Calculated %:
2.2.10. 3-(4-bromophenyl)-5-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-
C
18H18BrN3O: C 58.08; H 4.87; N 11.29 Found %: C 65.95; H 5.48; N
carbaldehyde (3j)
White, Yield 77%. Mp: 145 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O) 1598,
–
12.85.
–
1
–
ν
(C N) 1477. H NMR (300 MHz, CDCl ) δ 7.75 (m, 3H), 7.24–7.28 (d,
–
3
2.2.5. 3-(3-bromophenyl)-5-(4-(dimethylamino)phenyl)-4,5-dihydro-1H-
2H), 6.95–6.98 (d, 2H), 8.93 (s, 1H), 5.87 (dd, J = J = 17.9, 4.9 Hz, 1H),
pyrazole-1-carbaldehyde (3e)
3.79 (dd, J = 17.8, 11.6 Hz, 1H), 3.39 (dd, J = 11.7, 4.9 Hz, 1H). 13
C
Light green, Yield 78%. Mp: 200 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
NMR (CDCl3, 75 MHz): 160.09, 154.63, 142.77, 2132.11, 129.71,
128.14, 127.00, 125.36, 125.12, 54.57, 42.26, MS (m/z): 334.40 (M +
1), Calculated %: C14H11BrN2OS: C 50.16; H 3.31; N 8.36. Found, %: C
50.20; H 3.48; N 8.38.
–
–
–
1600,
ν
(C N) 1460. 1H NMR (300 MHz, CDCl3) 7.57–7.69 (m, 4H),
–
7.10–7.12 (d, 2H), 6.65–6.68 (d, 2H), δ 8.92 (s, 1H), 5.46 (dd, J = 17.6,
4.6 Hz, 1H), 3.72 (dd, J = 17.8, 11.7 Hz, 1H), 3.18 (dd, J = 11.8, 4.8 Hz,
1H), 2.91 (s, 6H).13C NMR (CDCl3, 75.47 MHz): 160.06, 154.72, 150.33,
132.03, 132.01, 130.00, 128.09, 128.07, 126.72, 124.84, 123.01,
112.71,58.90, 42.32, 40.51.MS (m/z): 372.20 (M + 1), Calculated %:
2.2.11. 3-(3-bromophenyl)-5-(thiophen-2-yl)-4,5-dihydro-1H-pyrazole-1-
carbaldehyde (3k)
Light green, Yield 79%. Mp: 160 ◦C. IR (neat, νmax cmꢀ 1):
ν
(C O)
–
C
18H18BrN3O: C 58.08; H 4.87; N 11.29. Found %: C 58.11; H 4.85; N
–
1
–
11.31.
1655,
ν
(C N) 1593. H NMR (CDCl , 300 MHz): 7.56–7.65 (m, 4H),
–
3
7.21–7.43 (m, 1H), 6.93–6.96 (m, 2H), 8.95 (s, 1H), 5.85 (dd, J = 17.8,
J = 4.6 Hz, 1H), 3.77 (dd, J = 17.8, 11.6 Hz, 1H), 3.36 (dd, J = 11.7, 4.6
Hz, 1H). 13C NMR (CDCl3, 75 MHz): 160.23, 155.81, 144.09, 132.33,
3