5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione

Asiri, Abdullah Mohamed; Alamry, Khaled Ahmed

doi:10.3390/M361

Open AccessShort Note

5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione

by

Abdullah Mohamed Asiri

^* and

Khaled Ahmed Alamry

Chemistry Department, Faculty of Science, King Abdul-Aziz University, Jeddah 21413, P.O.Box 9028, Saudi Arabia

^*

Author to whom correspondence should be addressed.

Molbank 2004, 2004(1), M361; https://doi.org/10.3390/M361

Submission received: 13 September 2003 / Accepted: 4 February 2004 / Published: 24 February 2004

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5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione 3 was prepared by Knoevenagel condensation of 3,4di-methoxybenzaldehyde 1 and N,N-diethylthiobarbituric acid 2 in ethanol using piperidine as a base [1,2].

N,N-diethylthiobarbituric acid 2 (6.0 g, 0.03 mol) and 3,4-dimethoxy- benzaldehyde 1 (5.0 g, 0.03 mol ) in ethanol (50 mL) was heated under reflux for ten minutes. Piperidine (1.5 mL) was added in one portion and the reflux was continued for further three hours. The reaction mixture was cooled to room temperature and the solid formed was filtered, washed with cooled ethanol (2x 50 mL) and dried. 5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione 3 was recrystallized from ethanol as deep yellow crystals (9.85 g, 94%).

M.p. 169 °C (EtOH, uncorrected).

UV 1max (nm; EtOH)/e (dm³.mol^-1.cm^-1) 260/2009, 370/2875 and 220/ 2475.

IR nmax (cm^-1; KBr Disk) 1694 (C=O), 1670 (N-CO-N), 1632 (C=C).

¹H-NMR (400 MHz; CDCl₃; Me₄Si) dH 8.48 (1H, s, olefinic Proton), 8.35 (1H), 7.84 (1H, d, J = 8.5 Hz), 6.96 (1H, d, J= 8.5 Hz), 4.51, 4.50 ( 4H, t, 2xCH₂), 4.00, 3.98 (5H, s, 2xMeO), 1.33, 1.28 ( 6H, q, 2xCH₃).

¹³C-NMR (100 MHz; CDCl₃; Me₄Si) d C 178.8 (C=S), 161.4, 160.9 (2xC=O), 154.74, 148.16 (CH olefinic), 133.6, 131.97, 122.5, 120.8, 117.38, 109.9, 55.4, 55.02 ( 2x CH₃O), 44.1, 43.5 ( 2xCH₂), 13.0, 12.7 (2xCH₃).

Anal.Calc. for C₁₇H₂₀N₂O₄S ( 348.418): C 58.60, H 5.79 , N 8.04; found : C 58.45, H 5.89, N 7.95.

Supplementary materials

Supplementary File 1Supplementary File 2Supplementary File 3

References

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

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MDPI and ACS Style

Asiri, A.M.; Alamry, K.A. 5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione. Molbank 2004, 2004, M361. https://doi.org/10.3390/M361

AMA Style

Asiri AM, Alamry KA. 5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione. Molbank. 2004; 2004(1):M361. https://doi.org/10.3390/M361

Chicago/Turabian Style

Asiri, Abdullah Mohamed, and Khaled Ahmed Alamry. 2004. "5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione" Molbank 2004, no. 1: M361. https://doi.org/10.3390/M361

APA Style

Asiri, A. M., & Alamry, K. A. (2004). 5-(3,4-Dimethoxybenzylidene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione. Molbank, 2004(1), M361. https://doi.org/10.3390/M361

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