Über die Synthese von 1-Aryl-und 1-Alkyl-2, 3-dimethyl-chinoxalinium-perchloraten. 2. Mitteilung. Synthese und 1H-NMR.-Spektren von 2,3-Dimethyl-1-phenyl-6-X-chinoxalinium-perchloraten

✍ Scribed by Dieter Schelz

• Publisher: John Wiley and Sons
• Year: 1978
• Tongue: German
• Weight: 679 KB
• Volume: 61
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19780610717

✦ Synopsis

On the Synthesis of 1‐Aryl‐ and‐1‐Alkyl‐2, 3‐dimethyl‐quinoxalinium Perchlorates. 2nd Communication1. Mitt.: [1].

. Synthesis and
^1^
H‐NMR.
Spectra of 2, 3‐Dimethyl‐1‐phenyl‐6‐X‐quinoxlinium Perchlorates

The synthesis of the title compounds (5) which have been useful as precursors for a lot of conventional and new‐type dyes [2‐8] has yet been limited to examples with XH [2] [3] [11] [15] and with electron‐donating [4] [12] or at best slightly electron‐accepting [1] [6] substituents X and R. We now describe a method suitable even for compounds 5 with strongly electron‐accepting substituents: N‐monosubstituted o‐phenylendiamines 4, were condensed with 2, 3‐butanedione and perchloric acid in mixed solvents containing an excess of diethyl ether. The products ‐ mostly substituted at position 6 of the quinoxalinium ring ‐ are chracterized by ^1^H‐NMR. spectra, elemental analyses and in most cases by isolation of the corresponding bases 6. Correlations of chemical shifts with Hammett's σ~p~ [18] are given by equations (1)‐(5).