Substituted Imidacloprid
1243
(m, 2H, NCH2CH2N), 3.84 (m, 2, NCH2CH2N), 4.627 (s, 2, CH2), 8.00 (s, 4-
Py-H), 8.22 (bs, 1, NH), 8.53 (s, 1H, 6-Py-H); dC 41.6, 45.3, 45.6, 121.9 (q, JC-
¼ 373.5 Hz), 125.6 (q, JC-F ¼33.6 Hz), 130.3, 136.7 (q, JC-F ¼ 4. Hz),
F
149.0, 161.4. MS m/z (%): 323 (Mþ, 3), 279 (44), 277 (100), 275 (17), 262
(11), 242 (51), 241 (80), 196 (14), 194 (42). Anal. Found: C, 37.41; H,
2.70; N, 21.41. Calcd. for C10H9ClF3N5O2: C, 37.11; H, 2.80; N, 21.64.
2-Chloro-5-methylnicotinamide (19). A mixture of 18 (460 mg, 3 mmol) and
1.2 ml of conc. H2SO4 was stirred at 60–658C for 3 h. The cooled mixture was
poured onto ice water, neutralized with sodium carbonate, and extracted with
ethyl acetate. Evaporation and recrystallization from toluene gave 310 mg
(59%) of product. Mp: 146–1478C (141–1438C).[15] IR (KBr): cm21 1700
(vs), 1565 (m), 1420 (s), 1360 (m), 1075 (m), 725 (m). NMR (CDCl3):
dH˙2.38 (s, 3H, CH3), 6.16 (bs, 1H, NH), 6.70 (bs, 1H, NH), 8.07 (d, 1H,
4-Py-H, J ¼ 1.2 Hz), 8.31 (d, 1H, 6-Py-H, J ¼ 1.2 Hz); dC 17.6, 129.1,
133.2, 141.1, 144.5, 151.86, 166.3. MS m/z (%): 172 (30), 170 (Mþ, 90),
155 (32), 153 (100), 127 (11), 125 (35), 90 (17).
Methyl 2-chloro-5-methylnicotinate (20). A mixture of 19 (620 mg,
3.62 mmol), trifluoroborane-diethyl ether (4 ml), and dry methanol (10 ml)
was heated at reflux temperature for 17 h. After concentration, the residue
was poured onto ice water. IPE extracts were washed with water and dried.
The product was purified by column chromatography on SiO2 with IPE.
Product (413 mg, 66%) was obtained as pale yellow liquid. IR (liquid):
cm21 1735 (vs), 1560 (s), 1435 (s), 1420 (vs), 1310 (s), 1235 (vs), 1135 (s),
1070 (s), 910 (m), 790 (m), 780 (m). NMR (CDCl3): dH˙ 2.37 (s, 3H, Py-
CH3), 3.95 (s, 3H, OCH3), 7.97 (d, 1H, 4-Py-H, J ¼ 1.2 Hz), 8.30 (d, 1H,
6-Py-H, J ¼ 1.2 Hz); dC 17.6, 52.9, 126.1, 132.3, 140.9, 147.2, 152.2,
165.2. MS m/z (%): 187 (18), 185 (Mþ, 57), 155 (32), 153 (100), 127 (8),
125 (35), 125 (25). HRMS (EI) m/z (Mþ): Calcd. for C8H8ClNO2,
185.0244; found, 185.0265.
Methyl 5-bromomethyl-2-chloronicotinate (21). To a suspension of 20
(160 mg, 0.86 mmol) and NBS (130 mg, 0.73 mmol) in CCl4, 10 mg of
benzoyl peroxide was added at 768C. The mixture was heated under reflux
for 1 h. After evaporating the solvent, the residue was separated by column
chromatography on SiO2 with hexane/IPE 4 : 1. Product (80 mg, 35%) was
isolated as a yellowish liquid, containing a small amount of 20. NMR
(CDCl3): dH˙ 3.97 (s, 3H, CH3), 4.48 (s, 2H, CH2), 8.21 (d, 1H, 4-Py-H,
J ¼ 2.6 Hz), 8.52 (d, 1H, 6-Py-H, J ¼ 2.6 Hz); dC 17.5, 53.0, 126.7, 132.8,
140.8, 140.9, 151.6, 164.4. MS m/z (%): 265 (17), 264 (100), 263 (Mþ,
24), 233 (20), 184 (17).
1-(6-Chloro-5-methoxycarbonyl-3-pyridylmethyl)-2-nitroiminoimidazo-
lidine (1f). This compound was obtained in 51% yield using 21 as described