1850
G.G. Levkovskaya et al. / Tetrahedron 67 (2011) 1844e1851
NMR (CDCl3, 100.61 MHz)
d
(ppm)¼150.4 (C-3), 128.9 (]CH), 128.1
from the mixture of 4i, 5f and 6a (MW exposure for 15 min); 1H
NMR (CCl4, HMDS, 400.13 MHz)
(C-5), 115.7 (]CH2), 101.4 (C-4), 36.2 (Me); IR (film): 3132, 3091,
3018, 2944, 2852, 1638, 1505 cmꢁ1; MS (EI, 70 eV), m/z (%): 142
(Mþ, 100), 127 (5), 116 (6), 107 (38), 81 (58), 66 (23), 54 (26), 42 (12).
Elemental analysis calcd for C6H7ClN2: C, 50.54; H, 4.95; Cl, 24.86;
N, 19.65. Found: C, 50.49; H, 4.93; Cl, 24.89; N, 19.61.
d
(ppm)¼6.20 (s, 1H, H-4), 5.31,
4.95 (s, s, 2H, ]CH2), 3.99 (t, J¼7.0 Hz, 2H, NCH2), 2.03 (s, 3H, Me),
1.84 (m, J¼7.0, 7.4 Hz, 2H, CH2), 0.91 (t, J¼7.4 Hz, 3H, Me); 13C NMR
(CCl4, HMDS, 100.61 MHz)
d
(ppm)¼152.3 (C-3), 137.2 (]C), 126.3
(C-5), 112.1 (]CH2), 101.6 (C-4), 44.3 (NCH2), 31.1 (CH2), 20.2 (Me),
15.5 (Me); IR (film): 3132, 3088, 2969, 2878, 1635, 1506 cmꢁ1; MS
(EI, 70 eV), m/z (%): 184 (Mþ, 4), 170 (100), 155 (19), 142 (34), 115
(16), 77 (9), 67 (14), 51 (11). Elemental analysis calcd for C9H13ClN2:
C, 58.67; H, 7.12; Cl, 19.00; N, 15.21. Found: C, 58.64; H, 7.10; Cl,
19.06; N, 15.19.
4.4.2. 5-Chloro-1-ethyl-3-vinylpyrazole (5b). Colourless liquid, bp
108e112 ꢀC (15 mm Hg), 5.51 g, 70% yield from 4b (MW exposure
for 30 min), 5.72 g, 73% yield from the mixture of 4b and 4f (MW
exposure for 10 min); 1H NMR (CDCl3, 400.13 MHz)
d
(ppm)¼6.55
(dd, J¼10.9, 17.8 Hz, 1H, CH]), 6.24 (s, 1H, H-4), 5.61 (dd, J¼1.0,
17.8 Hz, 1H, ]CH2), 5.23 (dd, J¼1.0, 10.9 Hz, 1H, ]CH2), 4.09 (q,
J¼7.2 Hz, 2H, CH2), 1.35 (t, J¼7.2 Hz, 3H, Me); 13C NMR (CDCl3,
4.4.7. 1-Benzyl-5-chloro-3-(prop-1-en-2-yl)-pyrazole
(5g). Light
yellow solid, mp 44e46 ꢀC (hexane), 10.73 g, 92% yield from the
100.61 MHz)
d
(ppm)¼150.4 (C-3), 129.0 (]CH), 127.0 (C-5), 115.5
mixture of 4j, 5g and 6b (MW exposure for 20 min); 1H NMR
(]CH2), 101.3 (C-4), 44.2 (NCH2), 15.0 (Me); IR (film): 3132, 3091,
2982, 2938, 2875, 1638, 1503 cmꢁ1; MS (EI, 70 eV), m/z (%): 156
(Mþ, 55), 141 (42), 128 (100), 114 (12), 105 (8), 93 (15), 67 (38), 52
(22). Elemental analysis calcd for C7H9ClN2: C, 53.68; H, 5.79; Cl,
22.64; N, 17.89. Found: C, 53.62; H, 5.78; Cl, 22.66; N, 17.85.
(CDCl3, 400.13 MHz)
d
(ppm)¼7.31e7.17 (m, 5H, C6H5), 6.33 (s, 1H,
H-4), 5.43, 5.05 (s, s, 2H, ]CH2), 5.30 (s, 2H, NCH2), 2.08 (s, 3H, Me);
13C NMR (CDCl3, 100.61 MHz)
d
(ppm)¼136.8 (]C), 136.4 (C0-1),
128.8 (C0-3,5), 127.9 (C0-4), 127.7 (C-5), 127.4 (C0-2,6), 112.6 (]CH2),
102.2 (C-4), 53.0 (NCH2), 19.9 (CH3); IR (KBr): 3127, 3086, 3061,
3025, 2981, 2953, 2922, 1634, 1496 cmꢁ1; MS (EI, 70 eV), m/z (%):
232 (Mþ, 65), 217 (19), 197 (31), 91 (100), 77 (9), 65 (68), 51 (19).
Elemental analysis calcd for C13H13ClN2: C, 67.10; H, 5.63; Cl, 15.23;
N, 12.24. Found: C, 67.15; H, 5.66; Cl, 15.19; N, 12.25.
4.4.3. 1-Benzyl-5-chloro-3-vinylpyrazole (5c). Colourless liquid, bp
140e145 ꢀC (15 mm Hg), 7.87 g, 72% yield from 4c (MW exposure
for 30 min), 8.55 g, 78% yield from the mixture of 4c and 4g (MW
exposure for 10 min); 1H NMR (CDCl3, 400.13 MHz)
d
(ppm)¼
7.31e7.17 (m, 5H, C6H5), 6.61 (dd, J¼11.0, 17.7 Hz, 1H, ]CH), 6.33 (s,
1H, H-4), 5.67 (dd, J¼1.0,17.7 Hz,1H, ]CH2), 5.29 (dd, J¼1.0,11.0 Hz,
1H, ]CH2), 5.27 (s, 2H, NCH2); 13C NMR (CDCl3, 100.61 MHz)
4.4.8. 1-Benzyl-3-vinylpyrazole (5h). White solid, mp 35e37 ꢀC
(hexane), 7.80 g, 85% yield (MW exposure for 30 min); 1H NMR
(CDCl3, 400.13 MHz)
d
(ppm)¼7.26e7.11 (m, 5H, C6H5), 7.19 (d,
d
(ppm)¼150.9 (C-3), 136.1 (C0-1), 129.1 (]CH, C-5), 128.9 (C0-3,5),
J¼2.0 Hz, 1H, H-5), 6.75 (dd, J¼10.9, 17.9 Hz, 1H, ]CH), 6.33 (d,
J¼2.0 Hz, 1H, H-4), 5.68 (dd, J¼<1.0, 17.9 Hz, 1H, ]CH2), 5.22 (dd,
J¼<1.0, 10.9 Hz, 1H, ]CH2), 5.17 (s, 2H, NCH2); 13C NMR (CDCl3,
128.1 (C0-4),127.5 (C0-2,6),116.0 (]CH2),101.9 (C-4), 52.9 (NCH2); IR
(film): 3133, 3109, 3087, 3063, 3031, 3006, 2927, 2853, 1504 cmꢁ1
;
MS (EI, 70 eV), m/z (%): 218 (Mþ, 57), 183 (51), 91 (100), 77 (15), 65
(75), 51 (35). Elemental analysis calcd for C12H11ClN2: C, 65.91; H,
5.07; Cl, 16.21; N, 12.81. Found: C, 65.90; H, 5.07; Cl, 16.25; N, 12.77.
100.61 MHz)
d
(ppm)¼151.0 (C-3), 136.5 (C0-1), 130.2 (C0-5), 129.3
(]CH), 128.7 (C0-3,5), 127.9 (C0-4), 127.5 (C0-2,4), 114.7 (]CH2),
102.8 (C-4), 55.8 (NCH2). Elemental analysis calcd for C12H12N2: C,
78.22; H, 6.57; N, 15.21. Found: C, 78.27; H, 6.59; N, 15.20.
4.4.4. 1-Benzyl-5-chloro-3-(prop-1-enyl)-pyrazole (5d) (mixture of E
and Z-isomers). The ratio E/Z isomer z1:1. Colourless liquid, bp
187e190 ꢀC (15 mm Hg), 9.06 g, 78% yield (MW exposure for
4.4.9. 1,1-Dichloropenta-1,4-dien-3-one (7). Compound 7 was iso-
lated under distillation (>150 ꢀC) of 3a or mixture of 3a and 3c, bp
70e72 ꢀC (25 mm Hg), 5e6% yield; 1H NMR (CCl4, HMDS,
10 min); 1H NMR (CDCl3, 400.13 MHz)
d
(ppm)¼7.27e7.15 (m, 5H,
C6H5), 6.31 (dd, 9.2, 15.7 Hz, 1H, CH]), 6.23e6.11 (m, J¼6.3, 7.2, 9.2,
400.13 MHz)
d
(ppm)¼6.82 (s, 1H, CH]CCl2), 6.48, 6.43 (d, d,
15.7 Hz, 1H, ]CH), 6.23 (s, 1H, H-4), 5.24 (s, 2H, NCH2), 1.93, 1.82 (d,
J¼10.5, 17.4 Hz, 1H, ]CH), 6.28 (d, J¼17.4 Hz, Z isomer, 1H, ]CH),
d, J¼6.3, 7.2 Hz, 3H, Me); 13C NMR (CDCl3, 100.61 MHz)
d
(ppm)¼
5.90 (d, J¼10.5 Hz, 1H, E isomer, ]CH); 13C NMR (CCl4, HMDS,
151.0 (C-3), 136.3 (C0-1), 128.8 (C0-3,5), 128.4 (]CH), 127.9 (C0-4),
127.5 (C-5), 127.4 (C0-2,6), 123.1 (]CH), 101.6 (C-4), 52.8 (NCH2),
18.4 (Me); IR (film): 3134, 3111, 3088, 3065, 3032, 3008, 2962, 2935,
2913, 2878, 2851, 1511 cmꢁ1; MS (EI, 70 eV), m/z (%): 232 (Mþ, 58),
141 (21), 141 (22), 106 (8), 91 (100), 77 (12), 65 (68), 51 (32). Ele-
mental analysis calcd for C13H13ClN2: C, 67.10; H, 5.63; Cl, 15.23; N,
12.04. Found: C, 67.13; H, 5.62; Cl, 15.28; N, 12.04.
100.61 MHz)
d
(ppm)¼236.0 (C]O), 126.6, 124.2, 122.0 (]CH),
107.1 (]CCl2); IR (film): 3077, 1704, 1587 cmꢁ1. Elemental analysis
calcd for C5H4Cl2O: C, 46.96; H, 2.67; Cl, 46.96. Found: C, 47.00; H,
2.65; Cl, 46.94.
Acknowledgements
Authors are grateful to the Russian Foundation of Basic Research
(RFBR) for financial support (grant no 11-03-00461).
4.4.5. 5-Chloro-1-ethyl-3-(prop-1-en-2-yl)-pyrazole (5e) (mixture of
S-trans, S-cis conformers). Colourless liquid, bp 124e128 ꢀC
(15 mm Hg), 5.82 g, 68% yield from the mixture 4h and 5e (MW
Supplementary data
exposure for 15 min); 1H NMR (CCl4, HMDS, 400.13 MHz)
d
(ppm)¼
6.20, 6.17 (s, s, 2H, 2H-4), 5.29, 4.93 (s, s, 2H, ]CH2), 5.27, 4.92 (d, d,
J¼1.2 Hz, 2H, ]CH2), 4.08 (q, J¼7.2 Hz, 4H, 2NCH2), 2.02, 2.00 (s, s,
6H, 2Me), 1.38 (t, J¼7.2 Hz, 3H, Me); 13C NMR (CCl4, HMDS,
Supplementary data includes NMR spectra of the products
obtained. Supplementary data associated with this article can be
include MOL files and InChiKeys of the most important compounds
described in this article.
100.61 MHz)
d
(ppm)¼152.2 (C-3), 137.3 (]C), 126.8 (C-5), 112.1 (]
CH2), 101.4 (C-4), 50.7 (NCH2), 23.7, 20.1 (Me), 11.6 (Me); IR (film):
3131, 3081, 2981, 2946, 2885, 1635, 1506 cmꢁ1; MS (EI, 70 eV), m/z
(%): 170 (Mþ, 100), 155 (24), 142 (48), 115 (21), 106 (12), 77 (10), 67
(14), 51 (11). Elemental analysis calcd for C8H11ClN2: C, 56.31; H,
6.50; Cl, 20.78; N, 16.42. Found: C, 56.37; H, 6.51; Cl, 20.74; N, 16.40.
References and notes
1. Elguero, J.; Goya, P.; Jagerovic, N.; Silva, A. M. S. In Targets in Heterocyclic Sys-
tems. Chemistry and Properties; Attanasi, O. A., Spinelli, D., Eds.; Italian Soc.
Chem.; 2002; Vol. 6, pp 53e99.
4. 4. 6. 5-Chloro-3-(prop-1-en-2-yl)-1-propylpyrazole
(5f). Colourless liquid, bp 130e133 ꢀC (15 mm Hg), 6.04 g, 65% yield
2. Grapov, A. F. Russ. Chem. Rev. 1999, 68, 697e707.