Abstract: A compound represented by the formula (I) wherein R1 and R2 represent amino groups that substitute at adjacent positions on the benzene ring, wherein one of the amino groups may have one alkyl group; R3 and R4 represent hydrogen atom, a C1-6 alkyl group, or a C1-6 alkoxy group, R5 and R8 independently represent a C1-6 alkyl group, R6 and R9 represent a carboxy-substituted C1-6 alkyl group, an alkoxycarbonyl-substituted C1-6 alkyl group, a sulfo-substituted C1-6 alkyl group, or an alkyl sulfonate-substituted C1-6 alkyl group, and R7 and R10 represent a C1-6 alkyl group, an aryl group, a C1-6 alkoxycarbonyl group, a vinyl group, a thienyl group, or a pyrrolyl group, and an agent for measurement of nitrogen monoxide containing the compound. Said compound can give a fluorescent substance that is free from change in fluorescence intensity in a wide pH range.

Abstract: A compound represented by the following general formula (I) or a salt thereof: wherein R1 represents hydrogen atom, an alkyl group, an alkoxy group, or hydroxy group; R2 represents a group represented by the following formula (A): wherein X1 to X4 represent hydrogen atom, an alkyl group, or 2-pyridylmethyl group, and m and n represent 0 or 1; Y represents a single bond or —CO—; R3 represents a carboxy-substituted aryl group, a carboxy-substituted heteroaryl group, benzothiazol-2-yl group, or 5-oxo-2-thioxo-4-imidazolyzinylidenmethyl group], and a fluorescent probe for zinc which comprises said compound or a salt thereof.

Abstract: A method for measuring hypochlorite ion, which comprises the steps of. (A) reacting, with hypochlorite ion, a compound represented by the following general formula (I): wherein R1 represents a 2-carboxyphenyl group which may be substituted; R2 represents a phenyl group which is substituted with a substituted or unsubstituted amino group; X1 and X2 each independently represents either hydrogen atom or a halogen atom; or a salt thereof; and (B) measuring fluorescence of a dearylated compound generated in the aforementioned step (A) or a salt thereof.

Abstract: A compound represented by the following formula (I): wherein R1 and R2 represent amino groups that substitute at adjacent positions on the phenyl ring, provided that either of R1 and R2 represents a mono(C1-6 alkyl)-substituted amino group and the other represents an unsubstituted amino group; and R3 and R4 independently represent hydrogen atom or an acyl group, and an agent for measurement of nitrogen monoxide which comprises said compound.

Abstract: A method for measurement of a target substance in a sample by means of fluorescence, which comprises the step of carrying out the measurement in the presence of (1) a specific fluorescent probe which specifically reacts with the target substance to generate fluorescence, and (2) a donor which, per se, has long-lived fluorescence and is capable of inducing fluorescence resonance energy transfer to the specific fluorescent probe that acts as an acceptor, provided that the donor forms no binding to the specific fluorescent probe by means of a chemical bond; and the step of converting fluorescence, wherein said fluorescence is resulted from a reaction between the acceptor and the target substance, into long-lived excitation fluorescence by the fluorescence resonance energy transfer which is induced on the acceptor.

Abstract: A compound represented by the following formula (I): wherein R1 and R2 represent amino groups that substitute at adjacent positions on the phenyl ring, provided that either of R1 and R2 represents a mono(C1-6 alkyl)-substituted amino group and the other represents an unsubstituted amino group; and R3 and R4 independently represent hydrogen atom or an acyl group, and an agent for measurement of nitrogen monoxide which comprises said compound.

Abstract: Compounds useful as agents for measurement of singlet oxygen, which are represented by the following general formula (I): wherein R1, R2, R3, R4, R5, and R6 independently represent a hydrogen atom, a halogen atom, a C1-6 alkyl group, or a C1-6alkoxyl group, R7 and R8 independently represent a C1-4alkyl group, and R9 represents a hydrogen atom, a C1-12 alkanoyl group, or acetoxymethyl group, or salts thereof.

Abstract: A compound represented by general formula (IA) or a salt thereof useful as a fluorescent probe for zinc: wherein R1 and R2 represent a hydrogen atom or a group represented by formula (A), wherein X1, X2, X3, and X4 represent a hydrogen atom, an alkyl group, a 2-pyridylmethyl group, or a protective group for an-amino group, and m and n represent 0 or 1, provided that R1 and R2 do not simultaneously represent hydrogen atoms; R3 and R4 represent a hydrogen atom or a halogen atom; and R5 and R6 represent a hydrogen atom, an alkylcarbonyl group, or an alkylcarbonyloxymethyl group, and R7 represents a hydrogen atom or an alkyl group.

Abstract: A compound represented by the following general formula (IA) or (IB) or a salt thereof which specifically traps a zinc ion and emits fluorescence, and is useful as a fluorescent probe for zinc: wherein R1 and R2 represent a hydrogen atom or a group represented by the following formula (A): wherein X1 to X4 represent a hydrogen atom, a 2-pyridylmethyl group, a 2-pyridylethyl group, a 2-methyl-6-pyridylmethyl group, or a 2-methyl-6-pyridylethyl group, provided that at least one is the group except a 2-pyridylmethyl group, and m and n represent 0 or 1, provided that they are not simultaneously 0; provided that R1 and R2 are not simultaneously hydrogen atoms; R3 and R4 represent a hydrogen atom or a halogen atom; R5 and R6 represent a hydrogen atom, an alkylcarbonyl group, or an alkylcarbonyloxymethyl group; and R7 represents a hydrogen atom or an alkyl group.

Abstract: A method for measuring hypochlorite ion, which comprises the steps of:

Abstract: A compound represented by the, following formula (I) or (II): 1

Abstract: A compound represented by the following general formula: wherein R1 and R2 represent amino groups present at adjacent positions each other on the phenyl ring; R3, R4, R5 and R6 independently represent a C1-6 alkyl group; R7, R8, R9 and R10 independently represent a hydrogen atom, a C1-6 alkyl group, an allyl group, or a halogen atom; R11 represents a hydrogen atom or a C1-18 alkyl group; and X− represents an anion, and an agent for nitric oxide measurement comprising said compound. The compound efficiently reacts with nitric oxide to give a fluorescent compound that emits strong fluorescence by irradiation with excitation light of a long wavelength. This fluorescent compound is characterized in that said compound is detectable in a fluorescence wavelength range hardly influenced by autofluorescence of cells, and its fluorescence intensity is not attenuated under an acidic condition.

Abstract: A compound useful for the measurement of nitrogen monoxide under a substantially neutral condition which is represented by the following formula (I): ##STR1## wherein R.sup.1 and R.sup.2 represent amino groups that substitute at adjacent positions on the phenyl ring; R.sup.3 and R.sup.4 independently represent a hydrogen atom or an acyl group; R.sup.5, R.sup.6, R.sup.7, and R.sup.8 independently represent a hydrogen atom, a C.sub.1-6 alkyl group, allyl group, or a halogen atom.