S. Achelle et al. / Tetrahedron 70 (2014) 2804e2815
2813
4.7. (E,E)4,6-Bis-[3-(2,6-tert-butyl-pyran-4-ylidene)-pro-
yield 68% (243 mg); mp: 69e70 ꢁC; 1H NMR (300 MHz, CDCl3)
d
1.13
penyl]-pyrimidine (5b)
(s, 9H), 1.19 (s, 9H), 5.60 (d, 1H, J¼12 Hz), 5.65 (d, 1H, J¼2 Hz), 6.20
(d, 1H, J¼2 Hz), 7.02 (d, 1H, J¼15 Hz), 7.48e7.53 (m, 1H), 7.57e7.63
(m, 1H), 7.80e7.81 (m, 3H), 8.74 (s, 1H); 13C NMR and JMOD
Red solid; obtained according to general procedure and purified
by column chromatography (SiO2, Petroleum ether/EtAcO, 1:1);
yield 73% (394 mg); mp: 124e125 ꢁC; 1H NMR (300 MHz, CDCl3)
(125 MHz, CDCl3)
d 164.8 (C), 164.2 (C), 152.2 (C), 145.3 (CH), 142.9
(C), 140.7 (C), 136.4 (C), 132.9 (CH), 129.9 (CH), 129.0 (CH), 128.6
(CH), 127.8 (CH), 121.5 (CH), 111.5 (CH), 105.0 (CH), 98.9 (CH), 35.8
(C), 35.4 (C), 27.9 (CH3), 27.8 (CH3). HRMS (ESI/ASAP) m/z calculated
for C24H29N2O [MþH]þ 361.2280, found 361.2280.
d
1.21 (s, 9H), 1.25 (s, 9H), 5.59 (d, 2H, J¼12.3 Hz), 5.69 (d, 2H,
J¼1 Hz), 6.19 (d, 2H, J¼14.7 Hz), 6.24 (d, 2H, J¼1 Hz), 6.80 (s, 1H),
7.89 (dd, 2H, J1¼12.3 Hz, J2¼14.5 Hz), 8.87 (s, 1H); 13C NMR and
JMOD (125 MHz, CDCl3)
d 164.6 (C), 163.9 (C), 162.9 (C), 158.2 (CH),
136.4 (C), 132.5 (CH), 122.6 (CH), 115.1 (CH), 111.2 (CH), 104.9 (CH),
99.0 (CH), 35.8 (C), 35.4 (C), 27.9 (CH3), 27.8 (CH3), HRMS (ESI/ASAP)
m/z calculated for C36H49N2O2 [MþH]þ 541.3794, found 541,3782.
4.12. (E)3-[3-(2,6-Diphenyl-pyran-4-ylidene)-propenyl]-pyr-
idazine (8a)
Red solid; obtained according to general procedure and purified
by column chromatography (SiO2, Petroleum ether/EtAcO, 1:1);
yield 43% (145 mg); mp: 160e161 ꢁC; 1H NMR (300 MHz, CDCl3)
4.8. (E)2-[3-(2,6-Diphenyl-pyran-4-ylidene)-propenyl]-pyr-
azine (6a)
d
5.89 (d, 1H, J¼12 Hz), 6.47 (d, 1H, J¼1.0 Hz), 6.55 (d, 1H, J¼15 Hz),
Red solid; obtained according to general procedure and purified
by crystallization from CH2Cl2/n-heptane; yield 47% (163 mg); mp:
6.99 (d, 1H, J¼1 Hz), 7.39e7.35 (m, 2H), 7.51e7.43 (m, 6H),
7.80e7.78 (m, 2H), 7.88e7.86 (m, 2H), 7.05 (dd, 1H, J1¼12 Hz,
J2¼15 Hz), 8.94 (dd, 1H, J1¼1.5 Hz, J1¼4.5 Hz); 13C NMR and JMOD
161e162 ꢁC; 1H NMR (300 MHz, CDCl3)
d
5.87 (d, 1H, J¼11.7 Hz),
6.44 (d, 1H, J¼1.0 Hz), 6.46 (d, 1H, J¼14.4 Hz), 6.95 (d, 1H, J¼1 Hz),
7.51e7.41 (m, 6H), 7.78e7.75 (m, 2H), 7.86e7.83 (m, 2H), 7.91 (dd,
(125 MHz, CDCl3)
d 157.5 (C), 151.6 (C), 150.8 (C), 146.8 (CH), 132.6
(C), 131.5 (C), 131.3 (C), 129.4 (CH), 128.1 (CH), 127.9 (CH), 127.2 (CH),
124.6 (CH),123.5 (CH), 123.2 (CH), 122.7 (CH),121.4 (CH),112.4 (CH),
106.7 (CH), 100.8 (CH). HRMS (ESI/ASAP) m/z calculated for
1H, J1¼11.7 Hz, J2¼14.4 Hz), 8.26 (d, 1H, J¼2.4 Hz), 8.46 (s, 2H); 13
C
NMR and JMOD (125 MHz, CDCl3)
d 153.0 (C), 152.5 (C), 152.3 (C),
24H19N2O [MþH]þ 351.1497, found 351.1496.
144.2 (CH), 143.7 (CH), 141.0 (CH), 134.0 (C), 133.0 (C), 132.8 (C),
130.8 (CH), 129.6 (CH), 129.4 (CH), 128.7 (CH), 125.1 (CH), 124.7
(CH), 122.4 (CH), 114.2 (CH), 108.3 (CH), 102.4 (CH). HRMS (ESI/
ASAP) m/z calculated for C24H19N2O [MþH]þ 351.1497, found
351.1498.
C
4.13. (E)3-[3-(2,6-Di-tert-butyl-pyran-4-ylidene)-propenyl]-
pyridazine (8b)
Yellow solid; obtained according to general procedure and pu-
rified by column chromatography (SiO2, Petroleum ether/EtAcO,
1:1); yield 59% (182 mg); mp: 141e142 ꢁC; 1H NMR (400 MHz,
4.9. (E)2-[3-(2,6-Di-tert-butyl-pyran-4-ylidene)-propenyl]-
pyrazine (6b)
CDCl3)
d
1.16 (s, 9H), 1.20 (s, 9H), 5.57 (d, 1H, J¼12 Hz), 5.64 (d, 1H,
Yellow sticky solid; obtained according to general procedure
J¼1.0 Hz), 6.15 (d, 1H, J¼1 Hz), 6.37 (d, 1H, J¼15 Hz), 7.33e7.23 (m,
2H), 7.81 (dd, 1H, J1¼12 Hz, J2¼15 Hz), 8.94 (dd, 1H, J1¼1.2 Hz,
and purified by column chromatography (SiO2, Petroleum ether/
EtAcO, 1:1); yield 65% (201 mg); 1H NMR (300 MHz, CDCl3)
d 1.19 (s,
J2¼4.5 Hz); 13C NMR and JMOD (125 MHz, CDCl3)
d 164.4 (C), 163.7
9H), 1.24 (s, 9H), 5.59 (d, 1H, J¼12 Hz), 5.66 (d, 1H, J¼1.8 Hz), 6.18 (d,
1H, J¼1.8 Hz), 6.33 (d, 1H, J¼15 Hz), 7.76 (dd, 1H, J1¼12 Hz,
J2¼15 Hz), 8.20 (d, 1H, J¼2.4 Hz), 8.41e8.40 (m, 2H); 13C NMR and
(C), 159.3 (C), 148.0 (CH), 135.9 (C), 131.3 (CH), 126.0 (CH), 123.8
(CH), 121.0 (CH), 111.0 (CH), 104.6 (CH), 98.6 (CH), 35.7 (C), 35.3
(CH), 27.9 (CH3), 27.7 (CH3), HRMS (ESI/ASAP) m/z calculated for
C20H27N2O [MþH]þ 311.2123, found 311.2124.
JMOD (125 MHz, CDCl3)
d 164.4 (C), 163.7 (C), 159.9 (C), 144.0 (CH),
143.4 (CH), 140.4 (CH), 135.4 (C), 131.3 (CH), 120.5 (CH), 111.2 (CH),
104.7 (CH), 98.7 (CH), 35.7 (C), 35.3 (C), 27.9 (CH), 27.8 (CH). HRMS
(ESI/ASAP) m/z calculated for C20H27N2O [MþH]þ 311.2123, found
311.2125.
4.14. General procedure for the synthesis of aldehydes 9 and
11
A
mixture of methydiazine (4 mmol) and benzene-1,4-
4.10. (E)2-[3-(2,6-Diphenyl-pyran-4-ylidene)-propenyl]-qui-
dicarboxaldehyde mono-(diethyl acetal) (832 mg, 4 mmol) in an
aqueous solution (30 mL) of sodium hydroxide (5 M) containing
Aliquat 336 (0.1 mol) was heated under reflux for 15 h After cooling,
the solid was filtered off, washed with water and dried. The
solid was then dissolved in acetone (50 mL), and a small amount
(0.5 mL) of concentrated hydrochloric acid was added under agi-
tation. The precipitate formed was filtered off and dissolved in di-
luted ammonia aqueous solution. The reaction mixture was
extracted with dichloromethane (3ꢂ50 mL), the combined organic
layer were washed with water, dried over MgSO4, and the solvent
was removed by evaporation under reduced pressure. A solid is
obtained and used without further purification.
noxaline (7a)
Red solid; obtained according to general procedure and purified
by column chromatography (SiO2, Petroleum ether/EtAcO, 1:1);
yield 51% (204 mg); mp: 210e211 ꢁC; 1H NMR (300 MHz, CDCl3)
d
5.93 (d, 1H, J¼12.3 Hz), 6.48 (s, 1H), 6.65 (d, 1H, J¼15 Hz), 7.02 (d,
1H, J¼1 Hz), 7.51e7.41 (m, 6H), 7.59e7.65 (m, 1H), 7.68e7.74 (m,
1H), 7.76e7.79 (m, 2H), 7.85e7.88 (m, 2H), 8.02e8.04 (m, 2H), 8.06
(dd, 1H, J1¼12.3 Hz, J2¼15 Hz), 8.83 (s, 1H); 13C NMR and JMOD
(125 MHz, CDCl3)
d 153.3 (C), 152.6 (C), 151.7 (C), 145.4 (CH), 142.9
(C), 140.9 (C), 134.8 (C), 133.0 (C), 132.7 (C), 130.0 (CH), 129.8 (CH),
129.5 (CH),129.0 (CH),128.7 (CH),128.1 (CH),125.1 (CH),124.7 (CH),
123.4 (CH), 114.5 (CH), 108.5 (CH), 102.5 (CH). HRMS (ESI/ASAP) m/z
calculated for C28H21N2O [MþH]þ 401.1654, found 401.1655.
4.15. 4-(2-Quinoxalin-2-yl-vinyl)-benzaldehyde (9)
4.11. (E)2-[3-(2,6-Di-tert-butyl-pyran-4-ylidene)-propenyl]-
Beige solid; yield 86% (894 mg); mp: 177e178 ꢁC; 1H NMR
quinoxaline (7b)
(500 MHz, CDCl3)
d
7.53 (d, 1H, J¼16.5 Hz), 7.79e7.73 (m, 2H), 7.81
(d, 2H, J¼8.0 Hz), 7.93 (d, 1H, J¼16.5 Hz), 7.94 (d, 2H, J¼8.0 Hz),
Red solid; obtained according to general procedure and purified
8.10e8.08 (m, 2H), 9.05 (s, 1H), 10.04 (s, 1H); 13C NMR and JMOD
by column chromatography (SiO2, Petroleum Ether/EtAcO, 7:3);
(125 MHz, CDCl3) d 191.5 (CH),149.8 (C),144.6 (CH),142.5 (C),141.91