4 -Nitro-1,3-diazole

Hydrazino-4-nitro-benzo-2-oxa-l,3-diazole Nbd-H Aldehydes and ketones 611... 

NBDPE 1,2-dipalmitoyl-sn-glycero-3-( A-(7-nitro-2-l, 3-benzooxa-diazol-4-yl))-phosphoethanolamin... 

Chlor-phenylazo )-3-(4-nitro-phenyl)-l, 2,4-oxa-diazol 97% Schmp. ... 

Nitro-l,2-Diazole or 4-Nitro-pyrpzole (called 4-Pyrazol in Ger), HC—NH — N... 

Amino-substituted selenophenes are in general unstable compounds, and are conveniently isolated as IV-acetyl or iV-formyl derivatives. An ortho situated electron-attracting substituent such as acetyl, formyl or nitro renders the amino compounds stable. Derivatives of this type can be diazolized and the resulting diazonium salts converted into azides (by reaction with azide ion) (75CR(C)(281)317) and selenocyanates (by reaction with selenocyanide ion) (79BSF(2)237). 3-Acetamidoselenophene can be thiocyanated or selenocyanated in the 2-position by treatment with bromine and potassium thiocyanate or potassium selenocyanate, respectively (78TL1797). 

In addition, the following have been described as diazo components 2,5-dichloro-4-nitroaniline (red) [49], 2-chloro-5-trifluoromethylaniline (yellow) [50], 4-nitro-2-trifluoromethylaniline (red) [51], 2-amino-5-trifluoromethyl-l,3,4-thia-diazole (red) [52], 3-methylmercapto-5-amino-l,2,4-thiadiazole (red) [53], 3-methyl-4-nitro-5-aminoisothiazole (blue-violet) [54], 2-amino-6-chlorobenzothia-zole (red) [55], and 3-amino-5-nitro-7-bromobenzisothiazole (blue with a red cast) [56],... 

Primary and secondary amines have been quantitated by thin layer chromatography after derivatization with 7-chloro-4-nitro-benzo-2-oxa-l,3-diazole (NBDC1, 12). The reagent has also been used for analysis of reduced nitrosamines employing adsorptive mode HPLC (13). 

Characteristics of the proton spectra of 5-nitro- and 7-nitrobenzisoselenazoles, 2-methyl-6-nitrobenzoselenazole [737] and 4-nitro- and 5-nitro-2,l,3-benzoseleno-diazoles are presented in [817] and [818], respectively. 

N -Iodoacetylethylenediamiwo)-naphthalene-1-sulfonic acid N-(Iodoacetylaminoethyl)-5-naphthylamine-1-sulfonic acid N-(lodoacetylaminoethyl)-8-naphthylamine-l-sulfonic acid 7-(p-Methoxybenzylamino-4-nitro-benz-2-oxy-1,3-diazole N-3-Pyrene maleimide Quinacrine mustard Rhodamine B isothiocyanate... 

Hermeken, H., Lindahl, R., Ostin, A., Vogel, M., Levin, J-0., Karst, U. (2003). Diffusive sampling of methyl isocyanate using 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ) as derivatizing agent. J. Environ. Monit. 5 100-5. 

For those without native fluorescence, two common approaches have been employed, namely, derivatization and indirect fluorescence. Derivatizing agents should be pure, low fluorescent, and stable, as well as react quickly and uniquely with the analytes and, thus, formed compounds should be strongly fluorescent and stable. These include dansyl chloride, fluorescamine, 4-clair-7-nitro-benz-2-oxa-l,3-diazole (NBD), o-phthaldialdehyde (OPA), fluorescein isothiocyanate (FITC), and naphthalene-2,3-dicarboxaldehyde (NDA), which have been used for the analyses of amino acids, peptides, proteins, thiols, and sugars with LOD in 1-100 nM range. Compared to LINF, approaches based on derivatization provide the advantages of relatively low cost and versatility in instrumentation, but they may suffer from contamination and loss of temporal information. 

Sample preparation Condition a Sep-Pak C18 SPE cartridge with 10 mL water, 5 mL MeOH, and 10 mL water. 1 mL Urine -I- 2 nmoles equilin -I- 100 p-L 1.5 M pH 3 acetate buffer, add to the SPE cartridge, wash with 10 mL 150 mM pH 3 acetate buffer, elute with 3 mL MeOH. Add HCl to the eluate so that the concentration of HCl is 500 mM, heat at 100° for 1.5 h, neutralize with sodium bicarbonate, extract with 2 mL chloroform. Evaporate the organic layer to dryness, reconstitute with 1 mL 5 pM 4-chloro-7-nitro-benzo-2-oxa-l,3-diazole (l D-Cl) in MeCN containing 25 nM 18-crown-6 and 15 mM potassium carbonate, heat at 80° for 30 min, filter, inject a 10-15 pL aliquot. 

GSTA2-2—Cumene hydroperoxide, fatty add hydroperoxides, dibenzo(a)-pyrene diol epoxide, CDNB-moderate, DCNB-moderate, 7-chloro-4-nitro-2-oxa-1,3-diazole, ethacrynic add (low moderate), PEITC, sulforophane. 

N-Aryl-C-nitroazoles. 1. C-Nitro-N-phenylazoles 12KGS1856. Diazole N-oxides 12AHC(106)1. 

For increased sensitivity, reagents that yield fluorescent products are employed. These include OPA, fluorescamine, and 4-fluoro-7-nitro-benzo-2-oxa-l, 3-diazole (NBD-F). Derivatization with OPA provides the best limits of detection for most amino acids. Although the products of OPA derivatization are unstable and decompose fairly rapidly to produce nonfluorescent 2,3-dihydro-lH-isoindol-l-ones, this is not a problem with postcolumn derivatization since the products are detected almost instantaneously. 

Other methods. Other methods of high detectability (determination range 0.005-10 pg ml include fluo-rimetric techniques such as binding fluorescamine, o-phthalaldehyde, danysyl chloride, 4-fluoro-7-nitro-benzo-2-oxa-l,3-diazole, l-anilinonaphthalene-8-sul-fonic acid, and hypochlorite-thiamine. Estimation of protein using ninhydrin (20-500 pg ml or... 

Another arylation reagent is 7-fluoro-4-nitro-benzo-2-oxa-l,3-diazol (NBD-F), which is also used as a chlorine compound (NBD-Cl) and which leads to derivatives that are suited for an amino acid analysis through HPLC separation ... 

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