4-Methoxy-7-nitrobenzo[c][1,2,5]oxadiazole TCI M3965

4-Methoxy-7-nitrobenzo[c][1,2,5]oxadiazole from TCI is a benzoxadiazole derivative, a fused aromatic heterocycle more commonly known to researchers as the NBD scaffold. The compound carries a nitro group at one end of the ring and a methoxy group at the opposite end, an arrangement that makes it both a fluorescent labelling reagent and a heterocyclic building block. In the laboratory, this material is used to attach a fluorescent tag to target molecules containing amine or thiol groups, so that molecules which were originally undetectable by optical means can be observed and quantified through fluorescence measurement or chromatographic detection.

The characteristics that lead analysts to select this reagent stem from its electronic properties. The strongly electron-withdrawing nitro group activates the ring so that the methoxy group at the opposing position acts as a leaving group in nucleophilic aromatic substitution. The reaction proceeds selectively with primary amines, secondary amines and thiols, producing strongly fluorescent NBD adducts. What makes this behaviour particularly useful is that the parent NBD compound is itself practically non-fluorescent, so emission appears only after labelling has taken place, and this property yields a low background against which the labelled species stands out clearly.

In Indonesian laboratories, this reagent is typically found in analytical chemistry, biochemistry and pharmaceutical research settings where amine- or thiol-containing analytes must be rendered detectable. It supports derivatisation work ahead of chromatographic separation, fluorescence-based assay development in university research groups, and synthetic programmes that build heterocyclic structures around the benzoxadiazole core. Quantities are generally modest, since derivatisation reagents are consumed in small amounts per sample batch.

• Pre-column derivatisation for chromatography: amines and thiols that lack a useful chromophore are converted into fluorescent NBD adducts, allowing sensitive detection of analytes that would otherwise pass undetected.
• Fluorescent labelling of amine-containing biomolecules: the selective reaction with primary and secondary amines attaches a reporter group to peptides and small biomolecules for subsequent fluorescence measurement.
• Thiol detection and quantification: the reagent reacts with thiol groups to produce strongly emitting adducts, providing a route to quantify sulfhydryl-bearing species in prepared sample solutions.
• Heterocyclic building block in synthesis: the activated ring and displaceable methoxy group let chemists introduce the benzoxadiazole core into larger target molecules through nucleophilic aromatic substitution.
• Low-background fluorescence assay development: because the unreacted reagent is essentially non-fluorescent, assays built on it show signal only after labelling, which simplifies method development considerably.

• Chemical name: 4-Methoxy-7-nitrobenzo[c][1,2,5]oxadiazole

Store the reagent in a cool, dark place in its original tightly closed container, protected from light and moisture, since nitroaromatic labelling reagents are generally light-sensitive and can degrade when exposed to humid air. Amber glass or the manufacturer's supplied container is suitable for long-term storage. Handle the material in a fume hood while wearing gloves, safety glasses and a laboratory coat, and avoid raising dust during weighing. Keep the container away from strong bases, reducing agents and sources of heat or ignition. Allow refrigerated material to reach room temperature before opening to prevent condensation, and consult the manufacturer's safety data sheet before first use.

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