Cleavable tetrazine used in bio-orthogonal drug activation

A tetrazine according to formula (1), or a salt thereof;

• wherein Formula (1) is:
• AT, BT, CT, DT each independently are selected from the group consisting of CR22, C═O, C═CR32, C—NR6, NR4, O, S, S(═O), or S(═O)2, provided that no sets consisting of adjacent atoms are present selected from the group consisting of —O—O—,—S—N(R4)—,—O—S—,—O—S(═O)—,—O—S(═O)2—, and —S—S—, and wherein one R2 or R4 group from BT and one R2 or R4 group from AT or CT can together be a bond, so as to form a double bond, and wherein two or more groups selected from R2, R3, R4, R5, R6 can together form a C6-C12 aryl, or a 3- to 8-membered heterocycle, a 3- to 8-membered annelated hetero(alkyl), a 3- to 8-membered spiro carbocycle or a 3- to 8-membered spiro heterocycle;
• XC is O, S, CR52 or NR6;
• LC is a self-immolative linker with f being 0 or 1;
• CA is Construct A;
• YC1 is O, S or a secondary amine or a tertiary amine, wherein these moieties are part of LC;
• YC2 is O, S or a secondary amine or a tertiary amine, wherein these moieties are part of CA, wherein f is 0 and g is 1, or wherein fis 1 and g is an integer from 1 to 9;
• wherein b, c, d and e are independently 0 or 1, provided that if b is 0 then c and d are 0, and if c is 0 then dis 0, and provided that if d is 1 then b and c are 1, and that if c is 1 then b is 1, and provided that if c is 0 then e is 1;
• wherein when f is 1 then YC1 is referred to as YC, and when f is 0, then YC2 is referred to as YC;
• wherein when b, e, and g are 1, c, d, and f are 0, YC is O or a secondary anime, and AT and BT together form —CH2—CH2-, then XC is S, CR52 or NR6;
• wherein each R1, R2, R3 and R5 is independently selected from the group consisting of H, (hetero)alkyl, aryl, heterocycle, carbocycle, F, Cl, Br, I, CF3, CF2—R′, NO2, N3, OR′, SR′, CN, C(═O)R′, S(═O)R′, S(═O)2R″, S(═O)2OR′, OS(═O)2R″, PO3R′2, Si—R″3, Si—O—R″3, B(OR′)2, S(═O)2NR′2, NR'S(═O)2R″, C(═O)NR′2, C(═S)NR′2, C(═NR′)NR′2, NR′2,
• NR′C(═O)R′, NR′C(═S)R′, NR′C(═O)NR′2, NR′C(═S)NR′2 wherein each R′ is independently selected from the group consisting of H, (hetero)alkyl, aryl, carbocycle, heterocycle, and each R″ is independently selected from the group consisting of (hetero)alkyl, aryl, carbocycle, heterocycle, wherein all (hetero)alkyl, aryl, carbocycle, heterocycle moieties comprised in R1, R2, R3 and R5 can be unsubstituted or substituted, and wherein two R′ or R″ groups can together form a ring;
• each R4 and R6 is independently selected from the group consisting of H, (hetero)alkyl, aryl, heterocycle, carbocycle, OR′, C(═O)R′, C(═O)NR′2, C(═S)NR′2, C(═NR′)NR′2, NR′2, such that no sets consisting of adjacent atoms are present selected from the group consisting of —N—N—,—N—O—,—N—S—,—N—Si-and-N—P—, and wherein each R′ is independently selected from the group consisting of (hetero)alkyl, aryl, carbocycle, heterocycle, wherein all (hetero)alkyl, aryl, carbocycle, heterocycle moieties comprised in R4 and R6 can be unsubstituted or substituted, and
• wherein two R′ groups can together form a ring;
• wherein in all of the above embodiments, one or more of R1, R2, R3, R4, R5, R6 and the self-immolative linker LC, may be bound to an SP, CB, and/or SP-CB;
• wherein SP is a spacer;
• wherein CB is Construct B;
• wherein Construct A is selected from the group consisting of small molecules, organic molecules, metal coordination compounds, inorganic molecules, organometallic molecules, biomolecules, drugs, polymers, resins, particles, gels, surfaces, cells, biological tissues, pathogens, solid supports, and combinations thereof;
• and
• wherein each Construct B is independently selected from the group consisting of small molecules, organic molecules, metal coordination compounds, inorganic molecules, organometallic molecules, biomolecules, drugs, polymers, resins, particles, gels, surfaces, cells, biological tissues, pathogens, solid supports, a radioisotope, and combinations thereof.