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24 February 2004

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1,3-Diethyl-5-(2-methoxybenzylidene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione

,
,
and
1
Chemistry Department, Faculty of Science, King Abdul-Aziz University, Jeddah 21413, P.O. Box 9028, Saudi Arabia
2
Department of Physics, Dillard University, New Orleans, LA 70112, USA
3
EJMAPS Organization, 1107 Carrolton Ave., Metairie, LA 70005, USA
*
Author to whom correspondence should be addressed.
Molbank2004, 2004(1), M359;https://doi.org/10.3390/M359
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1,3-Diethyl-5-(2-methoxybenzylidene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione 3 was prepared by Knoevenagel condensation of 2-methoxybenzaldehyde 1 and N,N-diethylthiobarbituric acid 2 in ethanol using piperidine as a base [1,2].
N,N-Diethylthiobarbituric acid 2 ( 1.50 g, 7.5 mmol) and 2-methoxybenzaldehyde 1 (1.02 g, 0.02 mol) in ethanol ( 30 mL) were heated under reflux for five minutes. Piperidine (0.5 mL) was added in one portion and the reflux was continued for two hours. The reaction mixture was cooled to room temperature and the solid formed was filtered, washed with cold ethanol ( 2x 20 mL) and dried. 1,3-Diethyl-5-(2-methoxybenzylidene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione 3 was recrystallized from ethanol as deep yellow crystals (2.03 g, 85%).
M.p. 108 °C (recrystallized from EtOH, uncorrected).
UV lmax (nm; CHCl3)/e (dm3.mol-1.cm-1) 406/16000 and 253/ 6060.
IR nmax ( KBr) cm-1 2980, 1674 (C=O), 1632 (C=C), 1391 (CS).
Theoretical (cm-1, AM1)= 1675.4, 1391.4, 1599.8
1H-NMR (400 MHz; CDCL3; Me4Si) d 8.90 (1H, s, CH=C), 8.10 (1H, d, J = 7.84 Hz ), 7.5 (1H, d, J = 7.24 Hz, J = 7.14 Hz ), 7.02 (1H, t(dd), J= 7.6 Hz), 6.94 (1H, d, J = 8.42 Hz ), 4.51, 4.50 ( 4H, t, CH2),3.99 ( 3H, s, CH3O), 1.33, 1.28 ( 6H, q, CH3).
13C-NMR (100 MHz, CDCL3; Me4Si) d 179 (C=S), 157.04, 155.6 (2xC=O), 148.16 (CH oliefinc), 134.4, 132.1, 122.5, 120.8, 119.2, 109.9, 43.7, 43.73 (CH2), 13.3, 13.1 (CH3).
Anal.Calc. for C16H18N2O3S ( 318.392): C 60.36, H 5.70 , N 10.07; found : C 60.21, H 5.82, N 10.16.

Supplementary materials

Supplementary File 1Supplementary File 2Supplementary File 3

References

  1. Jones, G. Org. React. 1967, 15, 204–599.
  2. Tanaka, K.; Chen, X.; Yoneda, F. Tetrahedron 1988, 44, 3241–3249.

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