Molbank 2006

Molbank 2006, M508

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

Synthesis of 2-(1,4-oxazino[2,3-b]quinoxalin-4-yl)ethanol

Craig A. Obafemi*¹, Wolfgang Pfleiderer² and Festus Taiwo¹

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

²Fachbereich Chemie, Konstanz University D-78457 Konstanz/Germany; E-mail:[email protected]

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: Oxazinoquinoxaline, 2,3-dichloroquinoxaline, diethanolamine

A mixture of 2,3-dichloroquinoxaline 1[1] (5.0 g, 25 mmol) and diethanolamine 2 (12 mL, 125 mmol) was heated to 130° C for 3 h, with magnetic stirring. The reaction mixture was cooled to room temperature and then poured into 300 mL of water. The resulting solid was filtered and then recrystallized from water to give white crystals of 2-(1,4-oxazino[2,3-b]quinoxalin-4-yl)ethanol 3 (5.3 g, 91%).

Melting point: 159 – 161°C. (Ref. [2]: 88%, m.p. 158°C)

IR (n_max, KBr, cm^-1): 3295 (OH), 1530, 1350, 1205, 1060

¹H-NMR (400 MHz, CDCl₃, d (ppm): 7.58 – 7.52 (m, 2H, Ar-H), 7.41 (t, 1H, Ar-H), 7.29 (t, 1H, Ar-H), 4.86 (t, 1H, OH, D₂O exchangeable), 4.48 (t, 2H, CH₂), 3.80 – 3.72 (m, 6H, (3 x CH₂) ).

¹³C-NMR (100 MHz, CDCl₃, d (ppm): 147.5, 142.7, 139.2, 134.9, 126.7, 126.1, 124.7, 123.8, 64.3, 58.1, 49.9, 46.2

MS (m/z, %): 231 (M⁺, 35.7), 212 ([M-H₃O.]⁺, 6.0), 201 ([M - HCHO]⁺, 26.4), 200 ([M - CH₂OH]⁺, 100), 187 ([M - CH₂ = CHOH]⁺, 70.9), 129 (24.8), 90 (15.2), 56 (41.5).

Acknowledgment

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

References

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

2. I.N. Goncharova, I. Ya. Postovskii J. Gen. Chem. USSR 1962, 32, 3271 – 3278. ¹H-NMR, ¹³C-NMR and mass spectra data are not given in this paper.