Molbank 2006, M473

http://www.mdpi.net/molbank/

 

1-ethoxycarbonylmethyl-3-(ethoxycarbonylmethylene)-2-oxo quinoxaline

 

Souad Ferfra, Noureddine H.Ahabchane and El Mokhtar Essassi*

 

Laboratoire de Chimie Organique Hétérocyclique, Faculté des Sciences, BP 1014, Avenue Ibn Batouta, Rabat, Maroc

e-mail:  [email protected]

*Author to whom correspondence should be addressed

 

Received: 13 February 2006 / Accepted: 18 February 2006/ Published: 28 February 2006

 

Keywords: quinoxaline, phase transfer catalysis, alkylation

 

 

 

The compound 3, which exists in tautomeric equilibria between enamine (form A) and methylene imine (form B), was prepared by addition of ethoxycarbonylmethyl chloride 2 (1.23g, 0.01 mol) to a solution of 3-(ethoxycarbonylmethylene)-2-oxo quinoxaline, 1 [1] (2.32 g, 0.01 mol) in 60 ml DMF, K2CO3 (1.38g, 0.01mol) and triethylbenzylammonium chloride (0.001 mol).  The mixture was stirred for 24 hours at room temperature. After filtration, the solvent was evaporated and the residue was recrystallized from ethanol affording 3 in 90% yield.

 

Melting point: 154-156°C.

 

IR (KBr, cm-1) : 1650 ( nN-C=O); 1720 (nN-C=O).

 

1H-NMR (250 MHz, CDCl3): δ= 11.20 (0.5H, s, NH, form A); 7.87-6.82 (8H, m, ar); 5.83 (0.5H, s, =CH, form A); 5.01 (1H, s, NCH2); 4.89 (1H, s, NCH2); 4.21 (8H, m, CH2); 3.95 (2H, s, CH2, form B); 1.27 (12H , m, CH3).

 

13C-NMR (250MHz, CDCl3): δ= 170.7 (Cq); 169.3 (Cq); 167.3 (Cq);  166.9 (Cq); 156.4 (Cq); 154.4 (Cq); 142.5 (Cq); 132.7 (Cq); 130.6 (CHar); 130.4 (CHar); 126.0 (Cq); 124.5 (CHar); 124.0 (CHar); 122.5 (CHar); 115.4 (CHar); 113.8 (CHar); 113.2 (CHar); 86.7 (=CH form A);  62.1 (CH2); 62.0 (CH2); 62.2 (CH2); 59.9 (CH2); 44.0 (NCH2); 43.6 (NCH2); 40.7 (CH2 form B); 14.4 (CH3); 14.1 (CH3).

 

MS (I.E): 318 [M+].

 

Reference

1. Kurasawa, Y. and Takada, A.; Heterocycles, 1985, 23, N°8

 

Sample Availability: Available from MDPI.

 

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