Molbank 2007, M527

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

 

1-(2-ethoxy-2-oxoethyl)-5-methyl-1H-pyrazole-3-ethyl 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 (6g; 39mmol) and potassium tert-butoxide (4.62g; 41.3mmol) in 120ml of anhydrous diethyl ether was refluxed for 75min. After cooling at 0¡ãC, a solution of ethylbromoacetate (8.46g; 50.6mmol) in 20ml of anhydrous diethyl ether was slowly added. The reaction mixture was stirred for one night at room temperature then filtered and the solvent was evaporated to dryness. The obtained residue was purified on alumina using hexane as eluant to give a 15% yield of the new compound 2 (yellow oil) (1.4g; 5.83mmol).

1H NMR spectrum of the compound 2 has a methyl group of pyrazol moiety at 2.33 ppm and a H4 proton at 6.80 ppm with a 4J(Me-H4) = 0.72 Hz. Theses couplings being characteristic of  a 5-methyl group [1-3]. Thus, the 1H NMR spectrum is consistent with the structure 2.

 

1H-NMR (CDCl3, 300 MHz ): ¦Ä= 6.80 (s, 1H, Pz-H); 5.10 (s, 2H, N-CH2-); 4.50 (q, 2H, -CH2-CH3 , J=7Hz); 4.40 (q, 2H, -CH2-CH3 , J=7Hz); 2.33 (s, 3H, -CH3); 1.40 (t, 3H, CH2-CH3, J=7Hz); 1.28 (t, 3H, CH2-CH3, J=7Hz).

 

13C-NMR (CDCl3, 75 MHz ): ¦Ä= 167.03; 162.35; 143.30; 141.02; 108.69; 62.05; 60.93; 51.30; 14.39; 14.10; 11.08.

 

Elemental analysis calculated for C11H16N2O4: C 55.00, H 6.71, N 11.66. Found: C 55.43, H 6.81, N 11.77.

 

IR (KBr, cm-1): 1720 and 1740 (C=O).

 

Mass Spectrometry (ESI): m/z =241(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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