S. Dalai, V. N. Belov, S. Nizamov, K. Rauch, D. Finsinger, A. de Meijere
FULL PAPER
1
1H NMR (250 MHz, CDCl3): δ = 2.42–2.56 (m, 2 H, 7-H), 2.87
(m, 2 H, 8-H), 6.06 (dt, J = 9.5 and 4.3 Hz, 1 H, 6-H), 6.71 (dt, J
= 9.5 and 1.8 Hz, 1 H, 5-H), 7.48–7.56 (m, 2 H), 8.16–8.27 (m, 2
3070 cm–1, 2936, 1634, 1549, 1507, 1321, 1165, 979, 699. H NMR
(250 MHz, CDCl3): δ = 2.38–2.51 (m, 2 H, 7-H), 2.88 (m, 2 H, 8-
H), 5.98 (dt, J = 9.5 and 4.4 Hz, 1 H, 6-H), 6.57 (dt, J = 9.5 and
H), 13.1 (br. s, 1 H, NH) ppm. 13C NMR (62.9 MHz, CDCl3): δ = 1.7 Hz, 1 H, 5-H), 7.22–7.36 (m, 5 H), 7.44–7.62 (m, 3 H), 7.76–
22.3 (–), 28.7 (–), 116.8 (Cquat, C-4a), 119.6 (+, C-5/C-6), 127.7 (+),
128.9 (+), 129.5 (+), 131.7 (+, C-6/C-5), 136.5 (Cquat), 153.3 (Cquat
7.82 (m, 1 H) 9.51 (br. s, 1 H, NH) ppm. 13C NMR (62.9 MHz,
,
CDCl3): δ = 22.5 (–), 38.7 (–), 117.2 (Cquat, C-4a), 119.3 (+, C-5/
C-2), 159.6 (Cquat, C-8a/C-4), 162.5 (Cquat, C-4/C-8a) ppm. MS C-6), 127.8 (+, C-6/C-5), 127.9 (+), 128.6 (+), 129.0 (+), 129.1 (+),
(70 eV): m/z (%) = 260/258 (32/100) [M+], 259/257 (40/98) [M+
–
130.2 (+), 130.9 (+), 131.1 (+), 131.5 (Cquat), 139.1 (Cquat), 140.8
H], 216/214 (28/8), 104 (14), 77 (20) [Ph+]. C14H11ClN2O (258.7): (Cquat), 155.8 (Cquat, C-2), 159.8 (Cquat, C-8a/C-4), 160.0 (Cquat, C-
calcd. C 65.00, H 4.29, N 10.83; found C 64.93, H 4.08, N 10.99.
4/C-8a) ppm. MS (70 eV): m/z (%) = 301 (28) [M+ +1], 300 (100)
[M+], 299 (40), 180 (38), 122 (43), 77 (78). C20H16N2O (300.4):
calcd. C 79.98, H 5.37, N 9.33; found C 79.64, H 5.24, N 9.57.
2-(o-Bromophenyl)-7,8-dihydro-3H-quinazolin-4-one (13c): Accord-
ing to GP 5 from the sulfone 12c (400 mg, 0.90 mmol) and KOtBu
(302 mg, 2.70 mmol) was obtained 13c (258 mg, 94%) as a pale
2-Methylthio-7,8-dihydro-3H-quinazolin-4-one (13g): According to
GP 5 from the sulfone 12g (336 mg, 1.00 mmol) and KOtBu
(336 mg, 3.00 mmol) was obtained 13g (181 mg, 93%) as a pale
yellow solid, m.p. 202 °C, R = 0.55 (Et O). IR (KBr): ν =
˜
f
2
1
3035 cm–1, 2836, 1665, 1491, 1324, 1183, 928, 767, 735. H NMR
(200 MHz, CDCl3): δ = 2.15–2.30 (m, 2 H, 7-H), 2.85 (m, 2 H, 8-
H), 6.04 (dt, J = 9.6 and 4.4 Hz, 1 H, 6-H), 6.59 (dt, J = 9.6 and
1.7 Hz, 1 H, 5-H), 7.28–7.81 (m, 4 H), 11.55 (br. s, 1 H, N–H)
ppm. 13C NMR (50.3 MHz, CDCl3): δ = 22.5 (–), 29.0 (–), 118.0
(Cquat, C-8a), 119.3 (+, C-5/C-6), 121.1 (Cquat), 127.7 (+), 127.9
(+), 131.1 (+), 131.8 (+), 133.7 (+), 134.3 (Cquat), 154.4 (Cquat, C-
2), 160.56 (Cquat, C-8a/C-4), 160.64 (Cquat, C-4/C-8a) ppm. MS
(70 eV): m/z (%) = 304/302 (96/100) [M+], 203/201 (98/80), 259/257
(24/26), 102 (28). C14H11BrN2O (303.2): calcd. C 55.47, H 3.66, N
9.24; found C 55.22, H 3.70, N 9.03.
yellow solid, m.p. 214 °C, R = 0.45 (Et O). IR (KBr): ν =
˜
f
2
2922 cm–1, 2836, 1641, 1623, 1540, 1271, 1138, 1203, 943. 1H NMR
(250 MHz, CDCl3): δ = 2.38–2.49 (m, 2 H, 7-H), 2.60 (s, 3 H), 2.76
(m, 2 H, 8-H), 5.98 (dt, J = 9.7 and 4.3 Hz, 1 H, 6-H), 6.61 (dt, J
= 9.7 and 1.8 Hz, 1 H, 5-H), 12.9 (br. s, 1 H, NH) ppm. 13C NMR
(62.9 MHz, CDCl3): δ = 13.3 (+), 22.4 (–), 29.4 (–), 114.6 (Cquat
,
C-4a), 119.3 (+, C-5/C-6), 126.0 (+, C-6/C-5), 157.0 (Cquat, C-2),
161.2 (Cquat, C-8a/C-4), 162.2 (Cquat, C-4/C-8a) ppm. MS (70 eV):
m/z (%) = 194 (100) [M+], 147 (12), 121 (16), 92 (14). C9H10N2OS
(194.3): calcd. C 55.65, H 5.19, N 14.42; found C 55.39, H 5.32, N
14.16.
2-(o-Fluorophenyl)-7,8-dihydro-3H-quinazolin-4-one (13d): Accord-
ing to GP 5 from the sulfone 12d (384 mg, 1.00 mmol) and KOtBu
(336 mg, 3.00 mmol) was obtained 13d (223 mg, 92%) as a pale
General Procedure (GP) 6: 2-Aryl-5,6,7,8-tetrahydro-3H-quinazolin-
4-one (14): A 50-mL flame-dried flask, flushed with nitrogen, was
charged with Pd/C (10% Pd w/w) in 10 mL of MeOH. This mixture
was stirred under H2 for 30 min, at which point a solution of 13 in
MeOH was added from a syringe, and stirring was continued, until
the reaction was complete. The reaction mixture was filtered
through a pad of Celite®, and the solvent was removed in vacuo to
yield 14 as a colorless solid.
yellow solid, m.p. 191 °C, R = 0.51 (Et O). IR (KBr): ν =
˜
f
2
3043 cm–1, 2934, 2886, 1653, 1559, 1327, 1220, 1181, 1122, 774. 1H
NMR (250 MHz, CDCl3): δ = 2.38–2.52 (m, 2 H, 7-H), 2.85 (m, 2
H, 8-H), 5.98 (dt, 3J = 9.5 and 4.4 Hz, 1 H, 6-H), 6.61 (dt, J = 9.5
and 1.7 Hz, 1 H, 5-H), 7.12–7.35 (m, 2 H), 7.41–7.54 (m, 1 H),
7.98–8.12 (m, 1 H), 11.51 (br. s, 1 H, NH) ppm. 13C NMR
2
(62.9 MHz, CDCl3): δ = 22.5 (–), 29.0 (–), 116.5 (+, d, JC–F
=
22.7 Hz, C-3Ј), 118.0 (Cquat, C-4a), 119.4 (+, C-5/C-6), 120.1 (Cquat
,
2-Phenyl-5,6,7,8-tetrahydro-3H-quinazolin-4-one (14a): According
to GP 6 the crude reaction mixture obtained from 13a (224 mg,
1.00 mmol), Pd/C (10% Pd w/w, 10 mg) in MeOH (20 mL) afforded
2
d, JC–F = 10.0 Hz, C-1Ј), 124.8 (+, d, 3JC–F = 3.3 Hz, C-6Ј), 127.8
4
3
(+, C-6/C-5), 130.9 (+, d, JC–F = 1.0 Hz, C-5Ј), 133.3 (+, d, JC–F
= 9.0 Hz, C-4Ј), 150.6 (Cquat, d, 3JC–F = 1.0 Hz, C-2), 160.0 (Cquat
,
after 4 h 14a (206 mg, 91%) as a colorless solid, m.p. 224 °C. IR
1
1
(KBr): ν = 2934 cm–1, 2848, 1634, 1550, 1319, 1165, 979, 698. H
C-8a/C-4), 160.3 (Cquat, C-4/C-8a), 160.4 (Cquat, d, JC–F
=
˜
251.4 Hz, C-2Ј) ppm. MS (70 eV): m/z (%) = 242 (100) [M+], 241
(85), 198 (24), 102 (12). C14H11FN2O (242.3): calcd. C 69.41, H
4.58, N 11.56; found C 69.22, H 4.83, N 11.45.
NMR (250 MHz, CDCl3): δ = 1.75–1.91 (m, 4 H), 2.50–2.65 (m, 2
H), 2.71–2.78 (m, 2 H), 7.40–7.58 (m, 3 H), 8.11–8.22 (m, 2 H),
12.38 (br. s, 1 H, NH) ppm. 13C NMR (62.9 MHz, CDCl3): δ =
21.8 (–), 21.9 (–), 22.3 (–), 31.9 (–), 120.2 (Cquat, C-4a), 127.5 (+),
2-(p-Benzyloxyphenyl)-7,8-dihydro-3H-quinazolin-4-one (13e): Ac-
cording to GP 5 from the sulfone 12e (400 mg, 0.85 mmol) and
KOtBu (285 mg, 2.54 mmol) was obtained 13e (258 mg, 92%) as a
pale yellow solid, m.p. 247 °C, Rf = 0.62 (CH2Cl2/MeOH, 25:1).
128.8 (+), 131.4 (+), 132.5 (Cquat), 153.2 (Cquat, C-2), 162.5 (Cquat
,
C-8a/C-4), 164.5 (Cquat, C-4/C-8a) ppm. MS (70 eV): m/z (%) = 227
(19) [M+ +1], 226 (100) [M+], 225 (51), 211 (31), 198 (10), 104 (21).
C14H14N2O (226.3): calcd. C 74.31, H 6.24, N 12.38; found C
74.34, H 6.55, N 12.29.
IR (KBr): ν = 3032 cm–1, 2943, 1646, 1606, 1512, 1305, 999, 753,
˜
677. 1H NMR (250 MHz, CDCl3): δ = 2.40–2.58 (m, 2 H), 2.85
(m, 2 H, 8-H), 5.15 (s, 2 H), 6.01 (dt, J = 9.6 and 4.4 Hz, 1 H, 6-
H), 6.70 (dt, J = 9.6 and 1.7 Hz, 1 H, 5-H), 7.02–7.18 (m, 2
H),7.30–7.62 (m, 5 H), 8.06–8.22 (m, 2 H), 12.23 (br. s, 1 H, NH)
ppm. 13C NMR (75.5 MHz, CDCl3): δ = 22.7 (–), 28.6 (–), 69.4
(–), 114.8 (Cquat, C-4a), 119.5 (+, C-5/C-6), 126.34 (+, C-6/C-5),
127.7 (+), 127.9 (+), 128.39 (+), 128.41 (+), 129.2 (+), 131.5 (Cquat),
136.5 (Cquat), 140.8 (Cquat), 155.9 (Cquat, C-2), 159.9 (Cquat, C-8a/
C-4), 160.9 (Cquat, C-4/C-8a) ppm. MS (70 eV): m/z (%) = 330 (55)
[M+], 239 (8), 91 (100) [C7H7+].
2-(p-Chlorophenyl)-5,6,7,8-tetrahydro-3H-quinazolin-4-one (14b):
According to GP 6 the crude reaction mixture obtained from 13b
(51.6 mg, 0.20 mmol), Pd/C (10 % Pd w/w, 20 mg) in AcOH
(10 mL) afforded after 8 h 14b (49 mg, 94%) as a colorless solid,
m.p. 255 °C. IR (KBr): ν = 3070 cm–1, 2936, 1634, 1549, 1507,
˜
1
1321, 1014, 929, 699. H NMR (250 MHz, CDCl3): δ = 1.74–1.93
(m, 4 H), 2.50–2.62 (m, 2 H), 2.66–2.79 (m, 2 H), 7.42–7.58 (m, 2
H), 8.13–8.24 (m, 2 H), 12.92 (br. s, 1 H, NH) ppm. 13C NMR
(62.9 MHz, CDCl3): δ = 21.8 (–), 21.9 (–), 22.4 (–), 32.0 (–), 120.4
(Cquat, C-4a), 127.4 (+), 128.9 (+), 129.0 (Cquat), 131.4 (Cquat),
157.5 (Cquat, C-2/C-8a), 157.6 (Cquat, C-8a/C-2), 162.5 (C-4) ppm.
2-(o-Biphenyl)-7,8-dihydro-3H-quinazolin-4-one (13f): According to
GP 5 from the sulfone 12f (300 mg, 0.68 mmol) and KOtBu
(224 mg, 2.00 mmol) was obtained 13f (177 mg, 87%) as a pale MS (70 eV): m/z (%) = 262/260 (16/51) [M+], 226 (100) [M+
–
yellow solid, m.p. 193 °C, R = 0.55 (Et O). IR (KBr): ν =
C1+1], 225 (52) [M+ – Cl], 211 (37), 104 (32), 77 (26).
˜
f
2
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Eur. J. Org. Chem. 2006, 2753–2765