References and Notes
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<A NAME="RG14807ST-12">12</A>
Static Pyrolysis of 8-j
The substrate (0.2 g) was introduced in the Pyrex reaction tube (12 cm length and
1.5 cm internal diameter). The tube was sealed under vacuum (0.02 m bar) and placed
in the pyrolyzer for 900 s at 300 °C. The content of the tube was then separated by
preparative high-performance liquid chromatography (HPLC) and was analyzed by 1H NMR, 13C NMR, IR and GC-MS. Relative and percent yields were determined from NMR.
<A NAME="RG14807ST-13">13</A>
Flash Vacuum Pyrolysis of 8a-j
The sample was volatilized from a tube in a Buchi Kugelrohr oven through a 30 × 2.5
cm horizontal-fused quartz tube and was heated externally by a cabolite Eurotherm
tube furnace MTF-12/38A to 600 °C. The products were collected in a U-shaped trap
cooled in liquid nitrogen. The whole system was maintained at a pressure of 10-2 Torr by an Edwards Model E2M5 high-capacity rotary oil pump, the pressure being measured
by a Pirani gauge situated between the cold trap and pump. Under these condition the
contact time in the hot zone was estimated to be 10 ms. Products collected in the
U-shaped trap were analyzed by 1H NMR, 13C NMR, IR and GC-MS. Relative and percent yields were determined from NMR.
Compounds 11a,c,d,f-h,j-n, 16, and 17 has been reported earlier and proved to be identical with products obtained here.
[19-27]
<A NAME="RG14807ST-14">14</A>
6-Methyl-1
H
-quinolin-4-one (
11b)
Mp 240-242 °C. IR (KBr): 3050 (NH), 1625 (CO) cm-1. LC-MS: m/z (%) = 159 (100) [M+]. 1H NMR (400 MHz, DMSO): δ = 2.39 (s, 3 H, CH3), 6.0 (d, 1 H, J = 7.2 Hz, quinoline-H3), 7.45 (d, 1 H, quinoline-H8), 7.48 (d, 1 H, quinoline-H7),
7.86 (d, 1 H, J = 7.2 Hz, quinoline-H2), 8.31 (s, 1 H, quinoline-H5), 11.72 (br s, 1 H, D2O exchangeable, NH). 13C NMR (DMSO, 100 MHz): δ = 21.55, 109.09, 119.18, 124.70, 125.96, 134.31, 134.57,
138.67, 140.50, 178.48. DEPT 135: δ = 21.55, 109.09, 119.18, 124.70, 125.96, 134.57,
140.50.
<A NAME="RG14807ST-15">15</A>
7-Bromo-1
H
-quinolin-4-one (
11e)
Mp 242-244 °C. LC-MS: m/z = 225 [M + 1]. 1H NMR (400 MHz, DMSO): δ = 6.04 (d, 1 H, H3, J = 7.37 Hz), 7.52 (d, 1 H, J = 8.56 Hz), 7.74 (s, 1 H, H-5), 7.82 (d, 1 H, J = 7.37 Hz, H2), 8 (d, 1 H, J = 8.56 Hz, H6), 11.22 (br, 1 H, NH). 13C NMR (100 MHz, DMSO): δ = 111.5, 120.4, 123.2, 126, 128.4, 132.7, 141, 143.4, 177.4.
<A NAME="RG14807ST-16">16</A>
5-Bromo-1
H
-quinolin-4-one (
11i)
Mp 234-236 °C. IR (KBr): 1645 (CO) cm-1. LC-MS: m/z = 225 [M + 1]. 1H NMR (400 MHz, DMSO): δ = 6.06 (d, 1 H, H3, J = 7.24 Hz), 7.41-7.47 (m, 3 H, ArH), 7.93 (d, 1 H, J = 7.24 Hz, H-2), 11.18 (br, 1 H, NH). 13C NMR (75 MHz, DMSO): δ = 110.3, 119.5, 121.5, 125.6, 127.2, 130.6, 139.3, 142, 177.
<A NAME="RG14807ST-17">17</A>
Smith MB.
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<A NAME="RG14807ST-18">18</A>
Pyrazino[1,2-
a
]pyrimidin-4-one (
19)
Mp 178-180 °C. IR (KBr): 1692 (CO) cm-1. LC-MS: m/z = 148 [M + 1]. 1H NMR (400 MHz, DMSO): δ = 6.67 (d, 1 H, J = 6.44 Hz, pyrimidine-H), 8.19 (d, 1 H, J = 4.64 Hz, pyrazine-H), 8.41 (d, 1 H, J = 6.44 Hz, pyrimidine-H), 8.73 (d, 1 H, J = 4.64 Hz, pyrazine-H), 9.13 (s, 1 H, pyrazine-H). 13C NMR (75 MHz, DMSO): δ = 109.6, 118.2, 133.0, 145.8, 154.2, 155.9, 156.8. DEPT 135:
δ = 109.6, 118.2, 133.0, 154.2, 155.9. Anal. Calcd for C7H5N3O (147.14): C, 57.14; H, 3.43; N, 28.56. Found: C, 57.53; H, 3.62; N, 28.83.
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