Compound or salt thereof, composition, chemiluminescence method, method for measuring chemiluminescence signal, reagent, reagent kit, and method for assaying analyte

A composition comprising:

• a compound represented by formula I, or a salt thereof:
• where,
• R1 represents a C1-8 alkyl group,
• each of R2 and R3 independently represents a C3-18 alkyl group or a C3-7 cycloalkyl group;
• R1 and R2, R1 and R3, or R2 and R3, together with a carbon atom to which they are bound, may form an optionally substituted ring;
• X represents a caging group;
• L is absent or represents a linker represented by formula L1, L2, L3, or L4:
• in each formula,
• M is absent or represents —O— or —NH—,
• a wavy line represents a linkage point to X,
• an asterisk represents a linkage point to Y;
• a benzene ring in formulae L1, L2, and L3 may be substituted with a substituent selected from the group consisting of halo group, alkyl group, cycloalkyl group, and alkoxy group;
• Y is absent or represents —O— or —NH—;
• R4 represents H or an electron withdrawing group bound to an ortho or a para position of the -Y-L-X group;
• A represents —C≡C-E where, E represents —COOH, —H, —CN, —COO-alkyl, or, an aryl group, a pyridinyl group, a pyridinium group, a 3H-indolyl group, or a 3H-indol-1-ium group, optionally substituted with a substituent, or an aryl group substituted with an electron withdrawing group;
• and
• an aqueous solvent.

A reagent for assaying an analyte in a sample, the reagent comprising a compound represented by formula I, or a salt thereof:

• where,
• R1 represents a C1-8 alkyl group,
• each of R2 and R3 independently represents a C3-18 alkyl group or a C3-7 cycloalkyl group;
• R1 and R2, R1 and R3, or R2 and R3, together with a carbon atom to which they are bound, may form an optionally substituted ring;
• X represents a caging group;
• L is absent or represents a linker represented by formula L1, L2, L3, or L4:
• in each formula,
• M is absent or represents —O— or —NH—,
• a wavy line represents a linkage point to X,
• an asterisk represents a linkage point to Y;
• a benzene ring in formulae L1, L2, and L3 may be substituted with a substituent selected from the group consisting of halo group, alkyl group, cycloalkyl group, and alkoxy group;
• Y is absent or represents —O— or —NH—;
• R4 represents H or an electron withdrawing group bound to an ortho or a para position of the -Y-L-X group;
• A represents —C≡C-E where, E represents —COOH, —H, —CN, —COO-alkyl, or, an aryl group, a pyridinyl group, a pyridinium group, a 3H-indolyl group, or a 3H-indol-1-ium group, optionally substituted with a substituent, or an aryl group substituted with an electron withdrawing group.

A reagent kit for assaying an analyte in a sample, the reagent kit comprising:

• a first reagent comprising:
• a compound represented by formula I, or a salt thereof:
• where,
• R1 represents a C1-8 alkyl group,
• each of R2 and R3 independently represents a C3-18 alkyl group or a C3-7 cycloalkyl group;
• R1 and R2, R1 and R3, or R2 and R3, together with a carbon atom to which they are bound, may form an optionally substituted ring;
• X represents a caging group;
• L is absent or represents a linker represented by formula L1, L2, L3, or L4:
• in each formula,
• M is absent or represents —O— or —NH—,
• a wavy line represents a linkage point to X,
• an asterisk represents a linkage point to Y;
• a benzene ring in formulae L1, L2, and L3 may be substituted with a substituent selected from the group consisting of halo group, alkyl group, cycloalkyl group, and alkoxy group;
• Y is absent or represents —O— or —NH—;
• R4 represents H or an electron withdrawing group bound to an ortho or a para position of the -Y-L-X group;
• A represents —C≡C-E where, E represents —COOH, —H, —CN, —COO-alkyl, or, an aryl group, a pyridinyl group, a pyridinium group, a 3H-indolyl group, or a 3H-indol-1-ium group, optionally substituted with a substituent, or an aryl group substituted with an electron withdrawing group;
• and
• a second reagent comprising a substance that releases the caging group.