7- Dimethylamino-3-methyl-2 quinoxalinone

Kwakman et al. [65] described the synthesis of a new dansyl derivative for carboxylic acids. The label, N- (bromoacetyl)-A -[5-(dimethylamino)naphthalene-l-sulfonyl]-piperazine, reacted with both aliphatic and aromatic carboxylic acids in less than 30 min. Excess reagent was converted to a relatively polar compound and subsequently separated from the derivatives on a silica cartridge. A separation of carboxylic acid enantiomers was performed after labeling with either of three chiral labels and the applicability of the method was demonstrated by determinations of racemic ibuprofen in rat plasma and human urine [66], Other examples of labels used to derivatize carboxylic acids are 3-aminoperylene [67], various coumarin compounds [68], 9-anthracenemethanol [69], 6,7-dimethoxy-l-methyl-2(lH)-quinoxalinone-3-propionylcarboxylic acid hydrazide (quinoxalinone) [70], and a quinolizinocoumarin derivative termed Lumarin 4 [71],... 

DMQPH = 6,7-dimethoxy-l-methyl-2(177j-quinoxalinone-3-proprionylcarboxylic acid hydrazide, HCPI = 2-(4-hydrazinocarbonylphenyl)-4,5-diphenyli-midazole, DBPM = 7V-[4 (6 dimethylamino-2-benzofuranyl)phenyl]maleimide, DNS-H = dansyl hydrazine, DBD H = 4 (AA -dimethylaminosulphonyl) 7-hydrazino-2,l,3-benzoxadiazole, DETBA = l,3-diethyl-2-thiobarbituric acid, DCIA = 7-dimethylamino-3- 4-[(iodoacetyl)amino]phenyl -4-methylcou marin, m-CED = 1, 2-bjs(3-chlorophenyl)ethylenediamine. 

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