Molbank 2007, M528

http://www.mdpi.org/molbank/

 

1-(2-ethoxy-2-oxoethyl)-5-methyl-1H-pyrazole-3-methyl carboxylate

 

Ahmed Attayibat 1,*, Smaail Radi 1, Yahya Lekchiri 2, Abdelkrim Ramdani 1 and  Maryse Bacquet 3

 

1 Laboratoire de Chimie Organique Physique, D¨¦partement de Chimie, Universit¨¦ Mohamed 1er, BP 524, 60 000 Oujda, Morocco

2 Laboratoire de Biochimie, D¨¦partement de Biologie, Facult¨¦ des Sciences, Universit¨¦ Mohamed 1er, BP 524, 60 000 Oujda, Morocco

3 Laboratoire de Chimie Macromol¨¦culaire, Universit¨¦ des Sciences et Technologies de Lille, 59655 Villeneuve d¡¯Ascq, France

* Author to whom correspondence should be addressed. E-mail: [email protected]

 

Received: 20 April 2006 / Accepted: 10 May 2006 / Published: 31 May 2007

 

Keywords: pyrazole, ethyl bromoacetate

 

 

A mixture of 1 (2g; 14.3mmol) and potassium tert-butoxide (1.68g; 15mmol) in 80ml of anhydrous diethyl ether was refluxed for 75min. After cooling at 0¡ãC, a solution of ethylbromoacetate (3.27g; 19.6mmol) in 15ml of anhydrous diethyl ether was gradually added. The reaction mixture was stirred for one night at room temperature then filtered and the solvent was eliminated under reduced pressure. The obtained residue was purified on alumina using hexane as eluant to afford a 30% yield of the new compound 2 (white solid) (0.97g; 4.3mmol). The second waited isomer has not been isolated. The product 2 was identified on the basis of its spectroscopic data. The coupling constant of the 1H NMR between the proton in position 4 and the methyl group of pyrazol ring 4J(Me-H4) was 0.71Hz. This coupling is characteristic of a 5-methyl group [1-3].

 

Melting point: 54-56¡ãC

 

1H-NMR (CDCl3, 300 MHz): ¦Ä= 6.41 (s, 1H, Pz-H); 4.80 (s, 2H, N-CH2-); 4.15 (q, 2H, -CH2-CH3 , J=7.13 Hz); 3.78 (s, 3H, -O-CH3); 2.20 (s, 3H, -CH3);1.23 (t, 3H, CH2-CH3 , J=7.13 Hz).

 

13C-NMR (CDCl3, 75 MHz): ¦Ä= 168.04; 163.45; 144.35; 142.62; 111.61; 64.95; 54.91; 54.22; 17.00; 13.49.

 

IR (KBr, cm-1): 1715 and 1735 (C=O).

 

Elemental analysis calculated for C10H14N2O4: C 53.09, H 6.24, N 12.38. Found: C 53.42, H 6.22, N 12.07.

 

Mass Spectrometry (ESI): m/z =227(M+1)

 

References:
1. Tarrago, G.; Ramdani, A.; Elguero, J.; Espada, M. J. Heterocycl. Chem. 1980, 17, 137.
2. Gready, J.E.; Hatton, P.M.; Sternhell, S. J. Heterocycl. Chem. 1992, 29, 935. 
3. Kumar, D.; Singh, S.P.; Martinez, A.; Fruchier, A.; Elguero, J.; Martinez-Ripoll, M.; Carrio, J.S.; Virgili, A. Tetrahedron 1995, 51, 4891.
  

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