Benzofurazan oxide chemistry: A novel reaction for the synthesis of quinoxaline monoxides

✍ Scribed by Graham S. Lewis; Arthur F. Kluge

• Book ID: 104236054
• Publisher: Elsevier Science
• Year: 1977
• Tongue: French
• Weight: 204 KB
• Volume: 18
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)83801-6

✦ Synopsis

We report a transformation of benzofurazan oxide (BFO) (1) into 3-substituted quinoxalinel-N-oxides by reaction with various a&unsaturated aldehydes-and ketones in the presence of morpholine. Reaction of 1 eq. BFO, 1.1 eq. trans-4-phenyl-3-buten-2-one (s), and 1.1 eq. morpholine in either acetonitrile or benzene at reflux for 24 hr gave 3-phenylquinoxaline-loxide (3) in 22% yield.2 Substitution of cinnamaldehyde for 2 under the same conditions gave 3 in 54% yield, and the use of P-cyclohexen-l-one as the enone component under the same conditions gave the morpholine amide 4 in 13% yield. 1 2 3 4 R=(:) 5 R = (+O) The structures assigned to 3 and 4 are based on a number of arguments. Compound 3, mp 134-135", was identical to an independently prepared sample3 by tic, ir, and mixture melting point comparison. Since 3 was prepared in the literature by selective oxidation of 2phenylquinoxaline, we obtained a further proof of structure for 3 through its transformation