Molbank 2006, M509

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

 

Synthesis of N, N-Dimethyl-3-phenoxyquinoxalin-2-amine

 

Craig A. Obafemi*1, Wolfgang Pfleiderer2

 

1Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria

2Fachbereich Chemie, Konstanz University D-78457 Konstanz/ Germany

E-mail: [email protected] ([email protected])

*Author to whom correspondence should be addressed

 

Received: 7 February 2005 / Accepted: 2 February 2006 / Published: 1 December 2006

 

Keywords:    Substitution reaction, 2,3-dichloroquinoxaline, phenol.

 

The two chloro groups in 2,3-dichloroquinoxaline 1 can be displaced by nucleophiles, a process that may take place in a stepwise manner [1].  1 was reacted with phenol 2 in dimethylformamide (DMF) to give N,N-dimethyl-3-phenoxyquinoxalin-2-amine 3.

 

 

A mixture of 2,3-dichloroquinoxaline 1 (5.0 g, 25 mmol), phenol (1.2 g, 13 mmol) and Na2CO3 (0.7 g, 7 mmol) in DMF (40 mL) was heated to reflux for 10 h. with magnetic stirring.  The reaction mixture was cooled and poured into water (200 mL) to give a solid product.  Flash vacuum column chromatography (silica gel, petroleum ether (b.p. 100¡ã)/EtOH 100:1) gave pure N,N-dimethyl-3-phenoxyquinoxalin-2-amine 3 (2.1 g, 62%, based on phenol). 

 

Melting point: 85 ¨C 86¡ãC.

 

IR (nmax, KBr, cm-1): 2940, 2880 (C-H), 1578 (C=C), 1516, 1196.

 

1H-NMR (400 MHz, CDCl3, d (ppm): 7.72 (d, 1H, J = 8.47 Hz, Ar-H), 7.52 (d, 1H, J = 9.25 Hz, Ar-H), 7.47 ¨C 7.34 (m, 3H, Ar-H), 7.31 ¨C 7.21 (m, 4H, Ar-H), 3.31 (s, 6H, 2 x CH3).

 

13C-NMR (100 MHz, CDCl, d (ppm): 152.9, 149.6, 147.7, 139.5, 135.4, 129.5, 127.3, 126.6, 125.7, 125.0, 124.9, 121.6, 40.6.

 

Acknowledgment

We thank the Alexander von Humboldt Foundation for a post-doctoral fellowship (CAO).

 

Reference

1. C.A. Obafemi and W. Pfleiderer Molecules 2004, 9, 229 ¨C 237.

 

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