Benzoxadiazole reagents

Heterocyclic fluorophores based on the benzoxadiazole nucleous, namely 4-nitrobenz-2-oxa-l,3-diazole (NBD) 14 derivatives/analogs, have been widely used as derivatization reagents for analysis purposes. Examples include the amino- or thiol reactive 4-fluoro-7-nitrobenz-2-oxa-l,3-diazole (NBD-F) 15 and 4-chloro-7-nitrobenz-2-oxa-1,3-diazole (NBD-C1) 16 [45-50] and the thiol-reactive /V-((2-(iodoacetoxy)ethyl)-/V-methyl)amino-7-nitrobenz-2-oxa-1,3-dia-zole (IANBD ester) 17 [51] and 7-chlorobenz-2-oxa-l,3-diazole-4-sulfonate (SBD-C1) 18 [52], NBD-F and NBD-C1 derivatives can be excited at about 470 nm by using the relatively inexpensive and reliable argon ion lasers or newer diode pumped solid state (DPSS) lasers. NBD-F has been used as a labeling tag in various capillary electrophoresis (CE) experiments for amino acids [53-57] including the monitorization of in vivo dynamics of amino acids neurotransmitters [58]. 

Klinker CC, Bowser MT (2007) 4-Fluoro-7-nitro-2, 1, 3-benzoxadiazole as a fluorogenic labeling reagent for the in vivo analysis of amino acid neurotransmitters using online microdialysis-capillary electrophoresis. Anal Chem 79 8747-8754... 

Figure 14 Representative fluorescence derivatization reagents used for PO-CL detection. DNS-CI, dansyl chloride DBD-F, 4-(A,A-dimethylaminosulphonyl-7-fluoro-2,l, 3-benzoxadiazole NDA, naphthalene-2,3-dicarboxaldehyde DNS-H, dansyl hydrazine DBD-H, 4-(iV,iV-dimethylaminosulphonyl-7-hydrazino-2,l,3-benzoxadiazole).

Reaction of this compound, or the considerably more explosive 2,6-dinitrobenzofur-oxan, with nucleophiles (secondary and tertiary amines, sodium hydroxide) showed evidence of Meisenheimer type complexes being formed - zwitteionic in the case of tertiary amines. Some of these broke down by elimination of water to give substituted benzoxadiazoles. All complexes and other isolated products are described as explosive. 4,6-Dinitrobenzofurazan iV-oxide Nucleophilic reagents See other furazan n-oxides... 

Toyo oka, T. Ishibashi, M. Takeda, Y Nakashima, K. Akiyama, S. Uzu, S. Imai, K. Precolumn fluorescence tagging reagent for carboxylic acids in high-performance liquid chromatography 4-substi-tuted-7-aminoalkylamino-2,l,3-benzoxadiazoles.t/.Chromotogr., 1991, 588, 61-71... 

Uzu, S. Imai, K. Nakashima, K. Akiyama, S. Use of 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,l,3-benzoxadiazole as a labelling reagent for peroxyoxalate chemiluminescence detection and its application to the determination of the p-blocker metoprolol in serum by high-performance liquid chromatography. Analyst, 1991, 116, 1353-1357... 

Vogel, M. and Karst, U., 4-Nitro-7-piperazino-2,l,3-benzoxadiazole as a reagent for monitoring of airhome isocyanates by liquid chromatography. Anal. Chem., lA, 6418-6426, 2002. 

The selection of a reagent depends on the required reactivity. Fluorescein [Figure 11.15(c)] and 7-nitro-2,l,3-benzoxadiazole (NBD) [Figure 11.15(f)] were used when highly sensitive reagents were required. Fluorescein is also used for fluorometric analysis of proteins. OrtAo-phthaldialdehyde (OPA) is a... 

Many benzofurazan reagents have been synthesized for labeling of carboxylic acids, e.g., 4-(amino-sulfonyl)-7-N-(2-animoethylamino)-2,l,3-benzoxadia-zole (ABD-AE), 4-(N,N-dimethylaminosulfonyl)-7-carverino-2,l,3-benzoxadiazole (DBD-CD), 4-nitro-7-(2-carbazoylpyrrolidine-l-yl)-2,l,3-benzoxadiazole (NBD-ProCZ), etc. 

Halogenobenzofurazan, e.g., 7-fluoro-2,l,3-ben-zoxadiazole-4-sulfonate (SBD-F), 4-(aminosulfonyl)-7-fluoro-2,l,3-benzoxadiazole (ABD-F), and 4-(N, N-dimethylaminosulfonyl)-7-fluoro-2,l,3-benzoxadia-zole (DBD-F), having reactive fluorine groups are synthesized. The application studies of these reagents on the determination of cysteine, GSH, and other thiol compounds by LC-FL detection have been reported with detection limits at the subpicomole level. 

The chiral derivatization reagents bearing an amino group include l-(4-dimethylamino-l-naph-thyl)ethylamine (DANE), 4-(3-aminopyrrolidin-l-yl)-7-nitro-2,l,3-benzoxadiazole (NBD-APy), and 4-(3-aminopyrroHdin-l-yl)-7-(N,N-dimethylaminosul-fonyl)-2,l,3-benzoxadiazole (DBD-APy). The derivatization of amino acids with these reagents yielded the corresponding amide derivatives, and the diastereo-meric amide derivatives produced were separated by normal or reversed-phase chromatography. 

Muramatsu, N. Toyo oka, T. Yamaguchi, K. Kobayashi, S. High-performance liquid chromatographic determination of erdosteine and its optical active metabolite utiUzing a fluorescent chiral tagging reagent, i -(—)-4-(N,N-dimethylaminosulfonyl)-7-(3-aminopyrrolidin-l-yl)-2,l,3-benzoxadiazole, J. Chromatogr.B, 1998, 719, 177—189. 

By treatment with ammonia, the sulfonyl chloride 175 was converted into 7-(aminosulfonyl)-4-fluoro-2,l,3-benzoxadiazole 176, which is used as a new fluorogenic reagent for thiols in HPLC. °... 

Amide [91366-65-3]. 7-Fluoro-4-benzofurazansulfonamide, 9CI. 4-Aminosulfonyl- 7-fluoro-2,l,3-benzoxadiazole C6H4FN3O3S M 217.180 Fluorogenic reagent for thiols. Mp 145-146°. 

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