Diethyl 2-Aryl-3-cyanopropene-1,1-dicarboxylates
665
Diethyl 3-bromo-2-phenylpropene-1,1-dicarboxylate (6a; C15H17BrO4)
1
Yield: 4.0 g (59%); m.p.: 56ꢀC (EtOH); Ir: ꢄ 3000±2950 (CH2), 1715, 1700 (2 CO) cmꢁ1; H
NMR: (DMSO-d6, ꢂ, 200 MHz): 0.95±1.30 (m, 2CH3), 3.95±4.23 (m, 2CH2), 4.40 (s, CH2), 6.79±
7.10 (m, 5Hatom) ppm; MS: m/z (%) 342 (M , 16), 261 (100), 297 (24).
Diethyl 3-bromo-2-(p-chlorophenyl)propene-1,1-dicarboxylate (6b; C15H16BrClO4)
1
Yield: 4.65 g (62%); m.p.: 64ꢀC (EtOH); IR; ꢄ 3308±2952 (CH2), 1712, 1700 (2CO) cmꢁ1; H
NMR (DMSO-d6, ꢂ, 200 MHz): 1.05±1.29 (m, 2CH3), 3.90±4.25 (m, 2CH2), 4.56 (s, CH2), 6.88±7.25
(m, 4Harom) ppm.
Diethyl 2-aryl-3-cyanopropene-1,1-dicarboxylates (general procedure)
To a solution of 0.02 mol 6a,b in 50 ml ethanol, 0.02 mol NaCN was added. The reaction mixture
was re¯uxed for 3 h, and the solvent was then evaporated in vacuo. The residue was triturated with
20 ml H2O; the solid product was collected by ®ltration, washed with H2O, dried over CaCl2, and
crystallized from an appropriate solvent.
Diethyl 3-cyano-2-phenylpropene-1,1-dicarboxylate (3a; C16H17NO4)
Yield: 3.90 g (68%); m.p.: 101ꢀC (EtOH); IR: ꢄ 3000±2950 (CH2), 2221 (CN). 1725, 1710
1
(2 CO) cmꢁ1; H NMR (DMSO-d6, ꢂ, 200 MHz): 0.96±1.35 (m, 2CH3), 3.80±4.23 (m, 2CH2), 4.52
(s, CH2), 6.74±7.20 (m, 5Harom) ppm; MS: m/z (%) 287 (M , 24), 242 (100), 197 (28).
Diethyl 2-(p-chlorophenyl)-3-cyanopropene-1,1-dicarboxylate (3b: C16H16CINO4)
Yield: 4.56 g (71%); m.p.: 109ꢀC (EtOH); IR: ꢄ 3010±2955 (CH2), 2218 (CN), 1710, 1700 (2CO)
1
cmꢁ1; H NMR (DMSO-d6, ꢂ, 200 MHz): 1.05±1.29 (m, 2CH3), 3.86±4.29 (m, 4H, 2CH2), 4.82
(s, 2H, CH2), 6.92±7.15 (m, 4Harom) ppm.
Diethyl 3-arylhydrazono-3-cyano-2-phenylpropene-1,1-dicarboxylates (general procedure)
To a stirred solution of 0.005 mol 3a in 50 ml EtOH containing 4 g NaOAc, 0.005 mol of the
appropriate arenediazonium chloride prepared by addition of 0.005 mol NaNO2 to 0.005 mol primary
aromatic amine in 2 ml concentrated HCl at 0±5ꢀC under stirring were added dropwise while cooling
at 0±5ꢀC and stirring. The reaction mixture was left at room temperature fro 2 h; then, the solid
product was collected by ®ltration and crystallized from an appropriate solvent.
Diethyl 3-cyano-2-phenyl-3-phenylhydrazonopropene-1,1-dicarboxylate (7a; C22H21N3O4)
Yield: 1.25 g (64%); m.p.: 186ꢀC (CHCl3); IR: ꢄ 3350±3318 (NH), 2218 (CN), 1715, 1695
1
(2CO) cmꢁ1; H NMR (DMSO-d6, ꢂ, 200 MHz): 0.95±1.23 (m, 2CH3), 3.87±4.02 (m, 2CH2), 6.72±
7.21 (m, 7Harom), 7.32±7.41 (m, 3Harom), 11.20 (br s, 1H, NH, exchangeable) ppm; MS: m/z
(%) 391 (M , 18), 345(100), 364(10).
Diethyl 3-(p-chlorophenylhydrazono)-3-cyano-2-phenylpropene-1,1-dicarboxylate
(7b; C22H20ClN3O4)
Yield: 1.44 g (68%); m.p.: 194ꢀC (CHCl3) IR: ꢄ 3370 (NH), 2220 (CN), 1722, 1700 (2CO) cmꢁ1
;
1H NMR (DMSO-d6, ꢂ, 200 MHz): 0.96±1.25 (m, 2CH3), 3.61±3.93 (m, 2CH2), 6.91±7.33
(m, 6Harom), 7.29±7.40 (m, 3Harom), 10.95 (br s, 1H, NH, exchangeable) ppm.