1946 J . Org. Chem., Vol. 67, No. 6, 2002
Palacios et al.
ration (5/1, hexane/ethyl acetate) gave 0.690 g (42%) of 18b
as a yellow oil: Rf ) 0.57 (1/2, ethyl acetate/hexane); IR (KBr)
ν 1618 cm-1; 1H NMR (300 MHz, CDCl3) δ 2.57-2.64 (m, 2H),
4.48-4.60 (m, 2H), 4.99-5.13 (m, 2H), 5.69-5.88 (m, 1H),
6.16-6.21 (m, 1H), 6.43 (s, 1H), 6.48-7.57 (m, 8H), 8.22 (s,
1H); 13C NMR (75 MHz, CDCl3) δ 36.0, 48.4, 108.9, 113.7,
117.3, 119.4-148.5 (m), 154.6; MS (EI) m/z 332 (M+, 12). Anal.
Calcd for C21H20N2S (332): C, 75.87; H, 6.06; N, 8.43; S, 9.64.
Found: C, 76.09; H, 5.96; N, 8.34; S, 9.57.
(KBr) ν 1434, 1248 cm-1; 1H NMR (300 MHz, CDCl3) δ 2.25-
2.32 (m, 2H), 4.03 (t, J ) 6.7 Hz, 2H), 4.91-4.98 (m, 2H), 5.54-
5.69 (m, 1H), 5.80 (dd, J ) 3.7 Hz, J ) 1.1 Hz, 1H), 5.95 (dd,
J ) 3.7 Hz, J ) 2.6 Hz, 1H), 6.61 (d, J ) 1.7 Hz, 1H), 7.20-
7.70 (m, 9H), 7.83 (d, J ) 2.3 Hz, 1H), 8.81 (d, J ) 2.0 Hz,
1H); 13C NMR (75 MHz, CDCl3) δ 35.6, 47.3, 107.5, 113.2,
116.7, 122.8, 126.9-137.4 (m), 140.1, 146.1, 149.1; MS (EI) m/z
350 (M+, 50). Anal. Calcd for C25H22N2 (350): C, 85.68; H, 6.33;
N, 7.99. Found: C, 85.39; H, 6.30; N, 7.87.
(1E,3Z)-4-P h en yl-1-(N-pr opar gyl-2-in dolyl)-3-(2-th ien yl)-
2-a za bu ta -1,3-d ien e (24). The general procedure was fol-
lowed using 1,1,1,4-tetraphenyl-3-(2-thienyl)-2-aza-1λ5-phos-
phabuta-1,3-diene (2.305 g) and 1-(N-propargyl)-2-indole-
carboxaldehyde 23 (0.910 g) in toluene. Chromatographic
separation (5/1, hexane/ethyl acetate) gave 0.960 g (51%) of
24 as a yellow oil: Rf ) 0.57 (1/2, ethyl acetate/hexane); IR
8-P h en yl-9-(2-t h ien yl)-10-a za -5H ,6H -in d en o[2,1-a ]in -
d ole (25). The general procedure was followed using (1E,3Z)-
4-phenyl-1-(N-propargyl-2-indolyl)-3-(2-thienyl)-2-azabuta-1,3-
diene (24) (1.830 g), and isolation of the reaction compound
by chromatographic separation (5/1, hexane/ethyl acetate) gave
1.240 g (68%) of 25 as a yellow solid: mp 151-152 °C; IR (KBr)
ν 1422 cm-1; 1H NMR (300 MHz, CDCl3) δ 5.02 (s, 2H), 6.65-
7.75 (m, 14H); 13C NMR (75 MHz, CDCl3) δ 46.7, 109.2-151.6
(m); MS (EI) m/z 364 (M+, 100). Anal. Calcd for C24H16N2S
(364): C, 79.09; H, 4.42; N, 7.69; S, 8.80. Found: C, 79.19; H,
4.36; N, 7.64; S, 8.81.
1
(KBr) ν 3397, 1626 cm-1; H NMR (300 MHz, CDCl3) δ 2.34
(s, 1H), 5.81-5.86 (m, 3H), 6.52 (s, 1H), 6.90-7.66 (m, 12H),
8.48 (s, 1H); 13C NMR (75 MHz, CDCl3) δ 34.4, 72.2, 79.2,
110.3-143.9 (m), 155.9; MS (EI) m/z 366 (M+, 10). Anal. Calcd
for C24H18N2S (366): C, 78.65; H, 4.95; N, 7.64; S, 8.75.
Found: C, 78.89; H, 5.06; N, 7.73; S, 8.63.
Gen er a l P r oced u r e for In tr a m olecu la r [4 + 2] Cy-
cloa d d ition Rea ction of 2-Aza d ien es. A 2-azadiene (3, 5,
15, 16, 18, 24) (5 mmol) solution in xylenes (20 mL) was stirred
at reflux (see Tables 1 and 2 in main text) until TLC indicated
the total disappearance of 2-azadiene. The crude of the reaction
was chromatographed on silica gel to give compounds 6, 17,
19, 21, and 25.
Gen er a l P r oced u r e for Ru O4 Oxid a tion s. To a solution
of 5H-benzopyrano[4,3-b]pyridine (6) (1 mmol) in CH3CN (2
mL) were added 2 mL of CCl4, 3 mL of H2O, and 877 mg (4.1
mmol) of NaIO4. The biphasic mixture was vigorously stirred,
and 5 mg of RuCl3‚H2O (2.2%) was added in one portion. After
60 min the mixture was diluted with 25 mL of CH2Cl2, and
the supernatant organic layer was decanted carefully; this
operation was repeated three times. The combined organic
layers were treated with Na2SO4 and concentrated under
reduced pressure. The residue was disolved in 15 mL of ether
and treated with a solution of freshly prepared diazomethane
in ether. The reaction mixture was stirred until the yellow
color of diazomethane disappeared. The mixture was washed
with brine, the aqueous layer was extracted with ether (2 ×
20 mL), and the combined organic layers were dried over Na2-
SO4 and concentrated under reduced pressure. The solid was
purified by flash chromatography (SiO2, hexane/EtOAc).
3,4-Diph en yl-5-oxo-ben zopyr an o[4,3-b]pyr idin e (9). The
general procedure was followed using 2,3-diphenyl-5H-ben-
zopyrano[4,3-b]pyridine (6b) (0.340 g), and isolation of the
reaction compound by chromatographic separation (5/1, hex-
ane/ethyl acetate) gave 0.290 g (83%) of 9 as a white solid:
2-(2-F u r yl)-3-p h en yl-5H -b en zop yr a n o[4,3-b]p yr id in e
(6a ). The general procedure was followed using (1E,3Z)-1-(2-
allyloxy-phenyl)-3-(2-furyl)-4-phenyl-2-azabuta-1,3-diene (3a )
(1.640 g), and isolation of the reaction compound by chromato-
graphic separation (5/1, hexane/ethyl acetate) gave 0.650 g
(40%) of 6a as a yellow solid, mp 92-93 °C. The same
compound 6a was obtained using (1E,3Z)-3-(2-furyl)-1-(2-
propargyloxy-phenyl)-4-phenyl-2-azabuta-1,3-diene (5a ) (1.62
1
g) in 60% yield (0.98 g): IR (KBr) ν 1490 cm-1; H NMR (300
MHz, CDCl3) δ 5.26 (s, 2H), 6.28 (d, J ) 3.0 Hz, 1H), 6.33 (s,
1H), 6.97-7.42 (m, 10H), 8.88 (d, J ) 7.8 Hz, 1H); 13C NMR
(75 MHz, CDCl3) δ 67.6, 111.2-156.4 (m); MS (EI) m/z 325
(M+, 100). Anal. Calcd for C22H15NO2 (325): C, 81.21; H, 4.65;
N, 4.30. Found: C, 81.19; H, 4.66; N, 4.34.
1
mp 160-162 °C; IR (KBr) ν 1725, 1420 cm-1; H NMR (300
MHz, CDCl3) δ 7.15-8.71 (m, 15H); 13C NMR (75 MHz, CDCl3)
δ 115.6, 117.1, 119.3, 124.7-163.0 (m); MS (EI) m/z 349 (M+,
60). Anal. Calcd for C24H15NO2 (349): C, 82.50; H, 4.33; N,
4.01. Found: C, 82.19; H, 4.36; N, 4.04.
2-(2-F u r yl)-3-p h en yl-5H-p yr id o[2,3-a ]p yr r olizin e (17a ).
The general procedure was followed using (1E,3Z)-1-(2-al-
lylpyrrolyl)-3-(2-furyl)-4-phenyl-2-azabuta-1,3-diene (15) (1.510
g), and isolation of the reaction compound by chromatographic
separation (5/1, hexane/ethyl acetate) gave 0.74 g (50%) of 17a
as a white solid, mp 105-106 °C. The same compound 17a
was obtained using (1E,3Z)-3-(2-furyl)-4-phenyl-1-(N-propar-
gyl-2-pyrrolyl)-2-azabuta-1,3-diene (16a ) (1.500 g) in 70% yield
Meth yl-3-p h en yl-5-oxo-ben zop yr a n o[4,3-b]p yr id in e-2-
ca r boxyla te (10). The general procedure was followed using
2-(2-furyl)-3-phenyl-5H-benzopyrano[4,3-b]pyridine (6a ) (0.320
g), and isolation of the reaction compound by chromatographic
separation (5/1, hexane/ethyl acetate) gave 0.260 g (80%) of
10 as a yellow solid: mp 160-161 °C; IR (KBr) ν 1739, 1421
cm-1; 1H NMR (300 MHz, CDCl3) δ 3.7 (s, 3H), 7.19-8.65 (m,
10H); 13C NMR (75 MHz, CDCl3) δ 52.8, 117.2-166.9 (m); MS
(EI) m/z 331 (M+, 80). Anal. Calcd for C20H13NO4 (331): C,
72.50; H, 3.95; N, 4.23. Found: C, 72.19; H, 4.06; N, 4.34.
1
(1.04 g): IR (KBr) ν 1432 cm-1; H NMR (300 MHz, CDCl3) δ
4.87 (s, 2H), 5.93-7.39 (m, 12H); 13C NMR (75 MHz, CDCl3) δ
48.4, 101.6-152.5 (m); MS (EI) m/z 298 (M+, 100). Anal. Calcd
for C20H14N2O (298): C, 80.52; H, 4.73; N, 9.38. Found: C,
80.39; H, 5.06; N, 9.44.
3-P h en yl-2-(2-t h ien yl)-5H ,6H -p yr id o[3,2-g]in d olizin e
(19b). The general procedure was followed using (1E,3Z)-4-
phenyl-1-(N-but-3-enyl-2-pyrrolyl)-3-(2-thienyl)-2-azabuta-1,3-
diene (18b) (1.660 g), and isolation of the reaction compound
by chromatographic separation (5/1, hexane/ethyl acetate) gave
1.110 g (68%) of 19b as a yellow solid: mp 123-124 °C; IR
Ack n ow led gm en t. The present work has been
supported by the Universidad del Pa´ıs Vasco (UPV-
170.123-G11/99) and by the Direccio´n General de In-
vestigacio´n Cient´ıfica of the Ministerio de Ciencia y
Tecnolog´ıa (Madrid DGI-MCYT, BQU2000-0217), and
C.A. thanks the Departamento de Educacio´n, Univer-
sidades e Investigacio´n of Gobierno Vasco for a post-
doctoral fellowship.
1
(KBr) ν 1575 cm-1; H NMR (300 MHz, CDCl3) δ 3.10 (t, J )
6.6 Hz, 2H), 4.14 (t, J ) 6.6 Hz, 2H), 6.29 (dd, J ) 3.9 Hz, J
) 2.7 Hz, 1H), 6.55 (d, J ) 3.9 Hz, 1H), 6.74-7.76 (m, 9H);
13C NMR (75 MHz, CDCl3) δ 28.1, 43.8, 107.5, 109.5, 117.6-
140.3 (m); MS (EI) m/z 328 (M+, 100). Anal. Calcd for
C
21H16N2S (328): C, 76.80; H, 4.91; N, 8.53. Found: C, 77.39;
H, 4.86; N, 8.50.
Su p p or t in g In for m a t ion Ava ila b le: Preparation, ele-
mental analysis, and spectral data (1H NMR, 13C NMR, IR,
and MS) for 2-azadienes 3c,d , 5b-f, 16c,e,f, and 18a ,e,f and
compounds 6b-f, 17c, 19a , and 21f. This material is available
2-(1-Bu t -3-en yl-1H -p yr r ol-2-yl)-3,5-d ip h en ylp yr id in e
(21e). The general procedure was followed using 4-phenyl-1-
(N-but-3-enyl-2-pyrrolyl)-2-azabuta-1,3-diene (18e) (1.250 g),
and isolation of the reaction compound by chromatographic
separation (5/1, hexane/ethyl acetate) gave 1.050 g (60%) of
21e as a yellow oil: Rf ) 0.39 (1/5, ethyl acetate/hexane); IR
J O016325V