Fluorogenic beta-lactamase substrate and associated detection method

A compound of formula (I):

• in which:
• W is —O— or —NR13—, with R13 being a C1-C4 alkyl or a hydrogen atom;
• R1 is such that HWR1, obtained after cleavage of the —C(O)—WR1 bond present in formula (I), belongs to the class of fluorophores;
• R2, R3 and R4 are defined as follows:
• either R2 is a C1-C4 alkyl, R3 is a C1-C4 alkyl or a hydrogen atom, and R4 is a C1-C4 alkyl;
• or R3 is a C1-C4 alkyl or a hydrogen atom and R2 and R4 are bonded to each other and form a —(CH2)p—Yq—(CH2)r— chain in direction of R2 toward R4, wherein
• Y is O, NR14, N(R14)2+or S,
• p=0, 1, 2, 3, 4 or 5,
• q=0 or 1,
• r=0, 1, 2, 3, 4 or 5,
• p+q+r=3,4,5, or 6,and
• each R14 represents independently a hydrogen atom, a C1-C6 alkyl, an amino protecting group, or -(L)q-GP, with q which is equal to 0 or 1, L which is a linking arm and GP which is a hydro solubilizing group;
• or R2 is a C1-C4 alkyl and R3 and R4 are bonded together and form, with the carbon atom to which they are bonded, an aliphatic carbocycle;
• R5 and R6 are identical or different and represent, independently of each other, a hydrogen atom, a C1-C4 alkyl, or a C5-C10 aryl;
• R7 is a hydrogen atom, or a group selected from C1-C4 alkyl and C1-C4 alkoxy;
• R8 represents a hydrogen atom;
• V represents an oxygen atom or a sulfur atom;
• n is 0 or 1;
• Z is —S—, —SO—or —CR9R10—;
• with R9 and R10 being identical or different and representing, independently of each other, a hydrogen atom or a C1-C4 alkyl;
• Q is H, a cation or R16, where R16 is selected from C1-C6 alkyl optionally substituted with an aryl or a —O(CO)—R, with R being independently selected from H, C1-C6 alkyl and C3-C6 cycloalkyl;
• and
• R11 is an organyl group, an organylamino group, an organyloxy group, or an organylthio group,
• X represents a bond, or a group selected from