2-Ethyl 4-methyl 5-amino-3-methylthiophene-2,4-dicarboxylate

Abdullah Mohamed Asiri

Chemistry Department, Faculty of Science, King Abdul-Aziz University, Jeddah 21589, P.O. Box 80203, Saudi Arabia. 

Tel.(+966)-2-6952293, Fax (+966)-2-6952293, E-mail: [email protected]

Received: 5 March 2003 / Accepted 4 June 2003 / Published 21 June 2003

Keywords: thiophene, Gewald reaction, methyl cyanoacetate

To a mixture contaning ethyl acetoacetate (13.02 g, 0.1 mol), methyl cyanoacetate (3.21 g, 0.1 mol) and sulfur (3.21 g, 0.1 mol) in ethanol ( 20 ml), morpholine (10 ml) was added dropwise over a period of 30 minutes at 35°C. The reaction mixture was heated at 65°C and stirred for 3 hrs, then allowed to cool to room temperature. The precipated powder was filtered and washed with ethanol (2x30 ml). Recrystallization from ethanol gave off-white powder (12.65 g, 52 %).

M.p. 95-97°C (Ethanol, uncorrected).

IR ( KBr) (cm^-1; KBr Disk) 3422, 3306 ( NH), 1681 (C=O), 1589 ( NH), 1331 (C-N).

¹H-NMR (400 MHz; CDCl₃; Me₄Si, dH): 1.33 (3H, t, J = 7.16 Hz, CH₃CH₂O), 2.7 ( 3H, s, CH3), 3.84 (3H, s, CH₃O), 4.26 ( 2H, q, J = 7.16 Hz, CH₃CH₂O), 6.57 ( 2H, bs, NH₂). 

¹³C-NMR (dC): 14.35, 16.0, 51.02, 60.38, 108.47, 147.89, 148.0, 162.83, 166.18, 166.46.

Elemental Analysis: Calculated for C₁₀H₁₃NO₄S (243.28): C 49.37 %, H 5.39 %, N 5.76 %, S 13.18 %; found : C 49.22 %, H 5.42 %, N 5.84 %, S 13.01 %.

References

1. Gewald, K.; Schinke, E.; Böttcher, H. Chem. Ber. 1966, 99, 94-100. 

2. Gewald, K.; Neumann, G. Chem. Ber. 1968, 101, 1933-1939.

Sample availability: available from the author. 

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