1802
C. O. Kappe et al.
PAPER
1H NMR (DMSO-d6): d = 2.31 (s, 3H, CH3), 2.43 (s, 3H, CH3), 3.48
(s, 3H, OCH3), 5.41 (d, 1H, J = 4.0 Hz, H-4), 7.11-7.22 (m, 4H,
ArH), 7.62 (br s, 1H, NH), 9.19 (br s, 1H, NH).
7.73 (m, 2H, Harom), 8.08-8.27 (m, 2H, Harom), 9.80 (br s, 1H, NH),
10.55 (br s, 1H, NH).
Ethyl 1,6-Dimethyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyri-
midine-5-carboxylate (4o)
Methyl 6-Methyl-4-(4-nitrophenyl)-2-oxo-1,2,3,4-tetrahydro-
pyrimidine-5-carboxylate (4h)
78%, mp 146–147 °C (EtOH) (lit.21 mp 146–147 °C, 48% yield).
86% yield, mp 246–248 °C (HOAc/EtOH) (lit.8b mp 235–237 °C,
41% yield).
IR (KBr): n = 3210, 1710, 1640, 1540, 1500 cm-1.
1H NMR (DMSO-d6): d = 1.18 (t, 3H, J = 7.5 Hz, CH3), 2.55 (s, 3H,
CH3), 3.51 (s, 3H, NCH3), 4.12 (q, 2H, J = 7.5 Hz, OCH2), 5.22 (d,
1H, J = 3.5 Hz, H-4), 7.18-7.41 (m, 5H, Harom), 9.88 (d, 1H, J = 3.5
Hz, NH).
IR (KBr): n = 3360, 3240, 3120, 1720, 1695, 1630 cm-1.
1H NMR (DMSO-d6): d = 2.29 (s, 3H, CH3), 3.56 (s, 3H, OCH3),
5.30 (br s, 1H, H-4), 7.53 (d, 2H, J = 8.5 Hz, Harom), 7.92 (br s, 1H,
NH), 8.23 (d, 2H, J = 8.5 Hz, Harom), 9.40 (br s, 1H, NH).
Isopropyl 6-Methyl-4-(3-nitrophenyl)-2-oxo-1,2,3,4-tetrahy-
dropyrimidine-5-carboxylate (4i)
Acknowledgement
94% yield, mp 205–208 °C (EtOH) (lit.4a mp 183–184 °C).
This work (C.O.K.) was supported by the Austrian Academy of Sci-
ences (APART 319) and the Austrian Science Fund (FWF, Project
P-11994-CHE. The support (R.S.V.) of the Texas Research Institute
for Environmental Studies (TRIES) is also acknowledged.
IR (KBr): n = 3240, 3110, 1715sh, 1705, 1650 cm-1.
1H NMR (DMSO-d6): d = 1.00 and 1.18 (2 d, 6H, J = 6.0 Hz each,
2 CH3), 2.28 (s, 3H, CH3), 4.84 (m, 1H, CH), 5.31 (d, 1H, J = 3.0
Hz, H-4), 7.65-7.77 (m, 2H, Harom), 7.91 (br s, 1H, NH), 8.09-8.19
(m, 2H, Harom), 9.38 (br s, 1H, NH).
References
tert.-Butyl-6-Methyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimi-
dine-5-carboxylate (4j)
# Present address: US Environmental Protection Agency, National
Risk Management Research Laboratory, 26 West Martin Luther
King Drive, MS 443, Cincinnati, Ohio, USA.
81% yield, mp 216–217 °C (EtOH) (lit.19 mp 209 °C, 55% yield).
IR (KBr): n = 3240, 3090, 1715sh, 1705, 1680, 1650 cm-1.
1H NMR (DMSO-d6): d = 1.30 (s, 9H, t-Bu), 2.24 (s, 3H, CH3), 5.12
(d, 1H, J = 3.0 Hz, H-4), 7.20-7.39 (m, 5H, Harom), 7.69 (br s, 1H,
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IR (KBr): n = 3310, 3140, 1710, 1665, 1640 cm-1.
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1H NMR (DMSO-d6): d = 1.13 (t, 3H, J = 7.5 Hz, CH3), 2.69 (m,
2H, CH2), 3.57 (s, 3H, OCH3), 5.18 (d, 1H, J = 3.0 Hz, H-4), 7.03-
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Ethyl 1,6-Dimethyl-2-oxo-4-phenyl-1,2,3,4-tetrahydropyrimi-
dine-5-carboxylate (4l)
89% yield, mp 180 °C (EtOH) (lit.20 mp 176–178 °C, 60% yield).
(4) a) Atwal, K. S.; Swanson, B. N.; Unger, S. E.; Floyd, D. M.;
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IR (KBr): n = 3220, 3100, 1710, 1680, 1620 cm-1.
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CH3), 3.11 (s, 3H, NCH3), 4.04 (q, 2H, J = 7.5 Hz, OCH2), 5.19 (d,
1H, J = 3.0 Hz, H-4), 7.21-7.39 (m, 5H, Harom), 7.99 (br s, 1H, NH).
b) Rovnyak, G. C.; Atwal, K. S.; Hedberg, A.; Kimball, S. D.;
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Ethyl 6-Methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimi-
dine-5-carboxylate (4m)
82% yield, mp 205–207 °C (EtOH) (lit.20 mp 207–208 °C, 42%
yield).
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IR (KBr): n = 3340, 3180, 3100, 1670, 1580 cm-1.
1H NMR (DMSO-d6): d = 1.12 (t, 3H, J = 7.5 Hz, CH3), 2.31 (s, 3H,
CH3), 4.02 (q, 2H, J = 7.5 Hz, OCH2), 5.20 (d, 1H, J = 3.0 Hz, H-
4), 7.20-7.41 (m, 5H, Harom), 9.68 (br s, 1H, NH), 10.31 (br s, 1H,
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Ethyl 6-Methyl-4-(3-nitrophenyl)-2-thioxo-1,2,3,4-tetrahydro-
pyrimidine-5-carboxylate (4n)
71% yield after flash silica gel chromatography (CHCl3/acetone
7:2) of the crude material, mp 208–209 °C (EtOH) (lit.9b mp 206–
207, 24% yield).
IR (KBr): n = 3180, 1715, 1660, 1595, 1530 cm-1.
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CH3), 4.05 (q, 2H, J = 7.5 Hz, OCH2), 5.35 (br s, 1H, H-4), 7.65-
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Synthesis 1999, No. 10, 1799–1803 ISSN 0039-7881 © Thieme Stuttgart · New York