FVP of 2,2-dimethyl-5-[(2-methyl-3-oxo-2,3-dihydropyridazin-
4-ylamino)methylene]-1,3-dioxane-4,6-dione 12
dH (d6-DMSO) 11.94 (1H, br, s), 8.25 (1H, br, m), 8.18
3
4
3
4
(1H, dd, J 8.3, J 1.5), 7.93 (1H, dd, J 7.8, J 1.5) and 7.44
(1H, dd, 3J 8.3, 3J 7.8); dC (d6-DMSO) 170.9 (quat), 138.3,
135.7 (quat), 132.1, 125.9 (quat), 124.7, 124.6, 121.9 (quat) and
115.2 (quat); m/z 215 (M+, 35%), 213 (M+, 53), 163 (85), 161
(100) and 84 (85).
FVP of 12 (0.1033 g, Tf 600 1C, Ti 190 1C, P 2.2–2.3 Â
10À2 Torr, t 45 min) gave two products, a white solid formed
at the exit point of the furnace and a yellow solid formed at the
liquid nitrogen level of the trap. The insoluble white solid was
suspended in acetone, and removed from the U-tube. Removal of
the acetone gave 7-methyl-1,7-dihydropyrido[2,3-d]pyridazine-
4,8-dione 22 (0.0127 g, 19%) as a white solid, mp 4310 1C;
(Found M+ 177.05318. C8H7N3O2 requires M 177.05328);
6-Chloroquinoline 30
The pyrolysate from FVP of 15 (288 mg, Tf 550 1C, Ti 220 1C,
P 1.0 Â 10À2 Torr, t 14 min) was washed through with
dichloromethane and the solvent removed to yield 6-chloro-
quinoline 30 (95 mg, 62%); dH 8.92 [1H, dd, 3J4,3 4.3 and 4J4,2
1.6, H(4)], 8.03–8.12 [(2H, m, H(2) and H(8)], 7.81 [1H, d, 4J5,7
3
dH (360 MHz, d6-DMSO) 8.32 (1H, s), 7.90 (1H, d, J 7.5),
6.44 (1H, d, 3J 7.5) and 3.79 (3H, s); dC (90 MHz, d6-DMSO)
175.3 (quat), 155.2 (quat), 140.2, 136.3 (quat), 133.5, 119.8,
117.6 (quat) and 39.4 (CH3); m/z 177 (M+, 13%), 159 (27),
136 (100), 120 (12), 105 (91) and 91 (45).
3
4
2.3, H(5)], 7.65 [1H, dd, J7,8 9.0, J7,5 2.3, H(7)] and 7.44
[1H, dd, 3J3,4 4.3 and 3J3,2 8.2, H(3)], consistent with reported
data;22 dC 150.3, 146.3 (quat), 135.2, 132.3 (quat), 130.8, 130.4,
128.7 (quat), 126.3 and 121.8; m/z 165 (M+, 34%), 163
(M+, 100), 128 (30), 101 (11) and 75 (15).
The yellow solid was dissolved in dichloromethane and the
solution removed from the U-tube; concentration of the
solution gave 1-methyl-1H-pyrrolo[3,2-c]pyridazine 24
(0.0308 g, 63%) as a brown-yellow solid mp 64–66 1C; (Found
M+ 133.06353. C7H7N3 requires M 133.06345); dH (360 MHz)
8.47 (1H, d, 3J 2.2), 8.39 (1H, d, 3J 5.4), 7.90 (1H, dd, 3J 5.4, 4J
0.9), 6.52 (1H, dd, 3J 2.2, 4J 0.9) and 4.42 (3H, s); dC (90 MHz)
158.3, 148.0 (quat), 144.9 (quat), 136.4, 116.8, 91.3 and
46.2 (CH3); m/z 133 (M+, 14%), 91 (14), 75 (14), 66 (59)
and 52 (100).
FVP of 3-[(2,2-dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethyl)-
amino]thiophene-2-carbaldehyde 16
FVP of 16 (21 mg, Tf 550 1C, Ti 120 1C, P 2.1 Â 10À2 Torr, t 8
min) yielded thieno[3,2-b]pyridine 31 and 4H-thieno[3,2-b]-
pyridin-7-one 32 in a ratio of 1 : 1 (identified by 1H NMR
spectroscopy).
FVP of 16 (21 mg, Tf 850 1C, Ti 130 1C, P 2.3 Â 10À2 Torr,
t 7 min) yielded thieno[3,2-b]pyridine 31 and 4H-thieno[3,2-
b]pyridin-7(4H)-one 32 in a ratio of 2 : 1. Spectral data for 32:
FVP of 5-[(5-chloro-2-methyl-3-oxo-2,3-dihydropyridazin-4-yl-
amino)methylene]-2,2-dimethyl-1,3-dioxane-4,6-dione 13
d
H (d6-DMSO) 7.99 (1H, d, 3J 5.5, thiophene-H), 7.87 (1H, d,
FVP of 13 (0.252 g, Tf 600 1C, Ti 200 1C, P 2.8–3.0 Â 10À2
Torr, t 11 min) gave a white solid condensate at the exit point
of the furnace and yellow solid deeper in the U-tube trap. The
entire pyrolysate was washed from the trap with methanol,
and the insoluble white solid filtered off to give 3-chloro-7-
methyl-1,7-dihydropyrido[2,3-d]pyridazine-4,8-dione 23 (0.0573
g, 34%), mp 4310 1C; (Found M+ 211.01416. C8H635ClN3O2
requires M 211.01431) dH (360 MHz, d6-DMSO) 13.01 (1H, br
s), 8.37 (1H, s), 8.31 (1H, s) and 3.79 (3H, s); dC (90 MHz,
d6-DMSO) 169.7 (quat), 155.0 (quat), 138.6, 135.4 (quat),
133.8, 123.6 (quat) and 39.5 (CH3) (one quaternary signal
not apparent); m/z 213 (M+, 33%), 211 (M+, 100), 183 (53),
159 (66) and 135 (72).
3J 7.2, pyridone-H), 7.27 (1H, d, 3J 5.5, thiophene-H) and
6.07 (1H, d, 3J 7.2, pyridone-H) consistent with literature
data;23dC (d6-DMSO) 173.5 (quat), 166.9 (quat), 137.9 (quat),
113.4 (2CH), 118.9 and 109.6; m/z 151 (M+, 100%), 135 (48),
134 (49), 125 (29), 96 (33) and 69 (48).
The pyrolysate obtained by FVP of 16 (61 mg, Tf 850 1C,
Ti 120 1C, P 2.1 Â 10À2 Torr, t 10 min) was washed from the
U-tube with warm CDCl3 (1 cm3) to yield thieno[3,2-b]-
pyridine 31 (17 mg, 57%); bp 145 1C (42 Torr) [lit.,24 129–131 1C
3
4
(16 Torr)]; dH 8.68 [1H, dd, J5,6 4.7 and J5,7 1.5, H(5)], 8.19
3
4
n
[1H, ddd, J7,6 8.2 J7,5 1.5 and J 0.9, H(7)], 7.76 (1H, dd,
3J 5.6 and nJ 0.4, thiophene-H), 7.57 (1H, dd, 3J 5.6 and nJ 0.9,
thiophene-H) and 7.25 [1H, ddd, 3J6,5 4.7, 3J7,6 8.2 and nJ 0.4,
H(6)]; dC 156.1 (quat), 147.4, 133.4 (quat), 130.8, 130.7, 125.3
and 118.8; m/z 135 (M+, 100%), 134 (33), 112 (20), 99 (20),
73 (29) and 69 (33).
The methanolic solution was absorbed onto alumina and
column chromatography (ethyl acetate) gave 4-chloro-1-
methyl-1H-pyrrolo[3,2-c]pyridazine 25 as an orange solid
(0.0214 g, 16%), mp 55–57 1C; (Found M+ 167.02473.
C7H635ClN3 requires M 167.02448); dH 8.43 (1H, d, J 2.0),
3
3
8.35 (1H, s), 6.53 (1H, d, J 2.0) and 4.51 (3H, s); dC 158.1,
144.8 (quat), 136.1, 126.2 (quat), 105.4 (quat), 98.9 and 46.0
Acknowledgements
(CH3); m/z 169 (M+, 30%), 167 (M+, 100) and 104 (13).
We are grateful to the EPSRC for a Research Studentship (to
A. P. G.), to Durham Organics and the EPSRC for a CASE
award (to W. J. O’N.) and to the Hungarian National
Research Funding (OTKA-K73389).
3,8-Dichloroquinolin-4(1H)-one 21
FVP of 14 (0.354 g, Tf 600 1C, Ti 190 1C, P 2.5–3.0 Â 10À2
Torr, t 15 min) gave a yellow-brown solid. Minor soluble
impurities were removed by distillation of dichloromethane
through the U-tube. Suspension of the residual solid in acetone
and removal of the solvent gave 3,8-dichloroquinolin-4-one 21
as a brown solid (0.128 g, 54%), mp 255–257 1C (decomp.);
(Found M+ 212.97454, C9H535Cl2NO requires M 212.97427);
Notes and references
1 Review, A. M. Gaber and H. McNab, Synthesis, 2001, 2059–2074.
2 For example, P. A. Derbyshire, G. A. Hunter, H. McNab and
L. C. Monahan, J. Chem. Soc., Perkin Trans. 1, 1993, 2017–2025.
ꢀc
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2010
New J. Chem., 2010, 34, 236–242 | 241