Molbank 2006

Molbank 2006, M510

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

Synthesis of 2-Chloro-3-(2-naphthyloxy)quinoxaline

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: 2,3-Dichoroquinoxaline, 2-naphthol.

A mixture of 2,3-dichloroquinoxaline 1 [1] (1.0 g, 5 mmol) and 2-naphthol (0.72 g, 5 mmol) in pyridine (10 mL) was heated to 130°C for 3 h, with magnetic stirring, to give a dark-brown reaction mixture. The reaction mixture was allowed to cool and then poured into cold water (50 mL). The resulting solid was filtered, dried and purified by column chromatography on silica gel, eluting with petroleum ether (b.p. 100^°) / ethanol (100:1) to afford 2-chloro-3-(2-naphthyloxy)quinoxaline 3 as colorless crystals (0.9 g, 58.0%).

Melting point: 163 – 165°C

¹H-NMR (400 MHz, DMSO-d₆, d (ppm): 8.10 – 7.90 (m, 5H, Ar-H), 7.76 – 7.67 (m, 3H, Ar-H), 7.62 – 7.54 (m, 3H, Ar-H).

¹³C-NMR (100 MHz, DMSO-d₆, d (ppm): 152.8, 150.1, 138.8, 138.6, 133.5, 131.0, 130.8, 129.6, 128.5, 127.7, 127.6, 127.4, 126.8, 126.6, 125.8, 121.5, 118.1.

MS (m/z, %): 308 ([M + 2]⁺ 31.8), 306 (M⁺, 100), 278 ([M-CO]⁺,19.0), 271 ([M-Cl]⁺, 23.6), 243 ([M-CO-Cl]⁺, 34.6), 163 ([M-C₁₀H₇O]⁺, 8.6), 127 (17.3), 115 (50.3), 102 (45.6), 90 (12.0), 75 (22.2).

Acknowledgment

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

Reference

1. C.A. Obafemi and Wolfgang Pfleiderer, Helv. Chim. Acta 1994, 77, 1549 – 1556.