DRUG CONJUGATE COMPRISING QUINOLINE DERIVATIVES

Abstract

Disclosed are compounds having the formula (I):

##STR00001##

wherein R.sub.1 represents a group: —NH.sub.2, —NHCOR.sub.a, —NHCOOR.sub.b, —(C.sub.2-C.sub.6)alkenylene-CO—NH—OH, —(C.sub.2-C.sub.6)alkynylene-CO—NH—OH or —OH; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; and R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; in the state of a base or acid or acid salts or base salts or in the form of hydrate or of solvate. Also disclosed are drug conjugates including such compounds.

Claims

1. A compound having the formula (I): ##STR00069## wherein: R.sub.1 represents a group: —NH.sub.2, —NHCOR.sub.a, —NHCOOR.sub.b, —(C.sub.2-C.sub.6)alkenylene-CO—NH—OH, —(C.sub.2-C.sub.6)alkynylene-CO—NH—OH or —OH; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; and R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; in the following state: base or acid, or salts of acids or salts of bases; or in the form of a hydrate or a solvate.

2. The compound according to claim 1, wherein R.sub.3 represents a hydrogen atom.

3. The compound according to claim 1, wherein R.sub.4 represents a hydrogen atom.

4. The compound according to claim 1, having the formula (Ia): ##STR00070## wherein: R.sub.1 represents a group: —NH.sub.2, —NHCOR.sub.a, —NHCOOR.sub.b, —(C.sub.2-C.sub.6)alkenylene-CO—NH—OH, —(C.sub.2-C.sub.6)alkynylene-CO—NH—OH or —OH; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; and R.sub.b represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; in the following state: base or acid, or salts of acids or salts of bases; or in the form of a hydrate or a solvate.

5. The compound according to claim 1, wherein R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, or —OCHF.sub.2.

6. The compound according to claim 1, wherein R.sub.1 represents a group: —NH.sub.2, —NHCOR.sub.a, —NHCOOR.sub.b, or —OH.

7. The compound according to claim 1, selected from: ##STR00071##

8. The compound according to claim 1, having the formula (Ib): ##STR00072## wherein: R.sub.5 represents a hydrogen atom, a group: —COR.sub.a, or —COOR.sub.b; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; and R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; in the following state: base or acid, or salts of acids or salts of bases; or in the form of a hydrate or a solvate.

9. The compound according to claim 1, wherein R.sub.1 represents a group: —(C.sub.2-C.sub.6)alkenylene-CO—NH—OH or —(C.sub.2-C.sub.6)alkynylene-CO—NH—OH.

10. The compound according to claim 1, having the formula (Ic): ##STR00073## wherein: W represents —CH═CH— or —C≡C—; n is 0, 1, 2, 3 or 4; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; and R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; in the following state: base or acid, or salts of acids or salts of bases; or in the form of a hydrate or a solvate.

11. The compound according to claim 10, selected from: ##STR00074##

12. A preparation method for preparing a compound according to claim 1, wherein R.sub.1 represents an —NH.sub.2 or —OH group, wherein: a compound having the formula (B): ##STR00075## wherein R.sub.2 is as defined according to claim 1 and R.sub.9 represents a —NO.sub.2 or —O-Benzoyl group; is brought into contact with a compound having the formula (D): ##STR00076## wherein R.sub.3 and R.sub.4 are as defined according to claim 1; so as to form, by an aromatic nucleophilic substitution reaction, or by a coupling reaction in the presence of a catalyst, the compound having the formula (E): ##STR00077## wherein R.sub.3, R.sub.4 and R.sub.2 are as defined according to claim 1, and R.sub.10 represents a —NO.sub.2 or —O-Benzoyl group; the compound having the formula (E) is subjected to a methylation reaction, then to a reduction or deprotection reaction so as to form the compound having the formula (I): ##STR00078## wherein R.sub.3, R.sub.4 and R.sub.2 are as defined according to claim 1, and R.sub.1 represents an —NH.sub.2 or —OH group, with R.sub.a and R.sub.b being as defined according to claim 1.

13. A preparation method for preparing the compound (Ic) according to claim 10, wherein: the compound having the formula (N): ##STR00079## wherein R.sub.3 and R.sub.4 are as defined according to claim 10; is brought into contact with a compound having the formula (O): ##STR00080## wherein R.sub.2 is as defined according to claim 10, so as to form, by an aromatic nucleophilic substitution reaction, followed by a methylation reaction, the compound having the formula (P): ##STR00081## wherein R.sub.3, R.sub.4 and R.sub.2 are as defined according to claim 10; the compound having the formula (P) is subjected to an organometallic coupling reaction with a group: —(C.sub.2-C.sub.6)alkenylene-CO—NH—O-(2-tetrahydropyranyl) or —C.sub.2-C.sub.6-alkynylene-CO—NH—O-(2-tetrahydropyranyl), then to a deprotection reaction, so as to form the compound having the formula (Ic): ##STR00082## wherein, , n, R.sub.3, R.sub.4 and R.sub.2 are as defined according to claim 10.

14. An intermediate compound, selected from: ##STR00083##

15. (canceled)

16. A compound having the formula (II): ##STR00084## wherein: Y.sub.1 represents —O—, —NH—, —NHCO—, —NHCOR.sub.a—, —NHCOO—, —NHCOOR.sub.b—, —(C.sub.2-C.sub.6)alkenylene-CO—NH—O— or —(C.sub.2-C.sub.6)alkenylene-CO—NH—O—; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; L represents a linking agent (linker); RM* is selected from RM and RM′, wherein RM is a reactive functional group that is able to form a covalent bond with a targeting agent moiety, and wherein RM′ is an RM moiety carrying at least one protecting group; in the following state: base or salts of bases; or in the form of a hydrate or a solvate.

17. The compound according to claim 16, wherein the L-RM* group is selected from among: ##STR00085## ##STR00086##

18. The compound according to claim 16, selected from among: ##STR00087## ##STR00088##

19. An antibody-drug conjugate having the formula (III): ##STR00089## wherein: Y.sub.1 represents —O—, —NH—, —NHCO—, —NHCOR.sub.a—, —NHCOO—, NHCOOR.sub.b, —(C.sub.2-C.sub.6)alkenylene-CO—NH—O— or —(C.sub.2-C.sub.6)alkenylene-CO—NH—O—; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; L represents a linking agent (linker); AC represents a targeting agent moiety; and wherein the DAR (drug-to-antibody [targeting agent] ratio) varies between 1 and 8.

20. A preparation method for preparing a compound having the formula (II) ##STR00090## wherein: Y.sub.1 represents —O—, —NH—, —NHCO—, —NHCOR.sub.a—, —NHCOO—, —NHCOOR.sub.b—, —(C.sub.2-C.sub.6)alkenylene-CO—NH—O— or —(C.sub.2-C.sub.6)alkenylene-CO—NH—O—; R.sub.2 represents a group: —OCH.sub.3, —OCH.sub.2CH.sub.3, —SCH.sub.3, —SCH.sub.2CH.sub.3 or —OCHF.sub.2; R.sub.3 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.c; R.sub.4 represents a hydrogen atom or a group: —CH.sub.3, —CN, —F, —Cl or —OR.sub.d; R.sub.a represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.b represents a group: —(C.sub.1-C.sub.5)alkylene- or —CF.sub.2—; R.sub.c represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; R.sub.d represents a group: —(C.sub.1-C.sub.5)alkyl or —CF.sub.3; L represents a linking agent (linker); RM* is selected from RM and RM′, wherein RM is a reactive functional group that is able to form a covalent bond with a targeting agent moiety, and wherein RM′ is an RM moiety carrying at least one protecting group; in the following state: base or salts of bases; or in the form of a hydrate or a solvate; the method comprising a reaction step of reacting a compound having the formula (I) according to claim 1, with a compound having the formula X-L″-RM* wherein: X represents a group that is capable of reacting with an R.sub.1 group as defined according to claim 1; L represents a linking agent (linker); RM* is selected from RM and RM′, wherein RM is a reactive functional group that is able to form a covalent bond with a targeting agent moiety, and wherein RM′ is an RM moiety carrying at least one protecting group; wherein the reaction between the —R.sub.1 moiety of the compound having the formula (I) and the compound having the formula X-L″-RM* results in the formation of a —Y.sub.1-L-RM* moiety.

21. The A preparation method according to claim 20, wherein RM* is RM, the method further comprising a deprotection step of deprotecting an RM′ moiety resulting in an RM group.

22. (canceled)

23. A pharmaceutical composition comprising an antibody-drug conjugate according to claim 19, in association with a pharmaceutically acceptable carrier.

24. A method of therapeutic treatment, wherein said method comprises administering to a subject in need thereof an antibody-drug conjugate according to claim 19.

25. The method according to claim 24, wherein the therapeutic treatment is, killing or inhibiting cell growth.

26. The method according to claim 24, wherein the therapeutic treatment is treatment of cancer.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples

Example 1: Preparation of 4-((3-amino-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile

1.1 General Schematic Representation

[0286] ##STR00046##

1.2 Preparation of 4-((4-methoxy-3-nitrophenyl)(methyl)amino)quinoline-2-carbonitrile

[0287] In a sealed tube the chlorinated heterocyclic compound and the aromatic amine derivative are successively added in 2 ml of dioxane.

[0288] One drop of HCl is then added to the mixture and the reaction medium is heated to 140° C., with agitation, for a period of 12 hours.

[0289] The mixture is cooled, and thereafter neutralised with NaOH.sub.aq. (5N) and the mixture is extracted with ethyl acetate (3×10 mL).

[0290] The combined organic phases are dried over Na.sub.2SO.sub.4 and concentrated under vacuum. The crude reaction mixture is dissolved in a Dimethylformamide (DMF) solution (5 mL) containing NaH at 0° C. To this mixture CH.sub.3I is added drop by drop and the reaction medium is placed at ambient temperature, under agitation, for a period of 2 hours.

[0291] The crude reaction mixture is concentrated and purified by means of chromatography on a silica column.

[0292] 4-((4-methoxy-3-nitrophenyl)(methyl)amino) quinoline-2-carbonitrile is obtained in solid form with a yield of 56%.

[0293] The melting temperature measured is 219.9-220.5° C.

[0294] Characterisation .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 8.11 (d, J=8.5 Hz, 1H); 7.71 (t, J=8.5 Hz, 1H) 7.61 (d, J=8.5 Hz, 1H); 7.58 (d, J=2.7 Hz, 1H) 7.42 (t, J=8.5 Hz, 1H) 7.34 (s, 1H) 7.05 (dd, J=9.1 Hz, J=2.8 Hz, 1H) 6.98 (d, J=9.1 Hz, 1H); 3.94 (s, 3H); 3.52 (s, 3H).

[0295] Characterisation .sup.13C NMR (75 MHz, CDCl.sub.3) δ: 153.9; 150.0; 149.3; 142.1; 139.9; 134.3; 130.9; 130.8; 128.2; 127.4; 124.5; 123.6; 118.4; 117.6; 114.9; 114.5; 56.9; 42.9.

[0296] Characterisation HRMS C.sub.18H.sub.15N.sub.4O.sub.3: 335.1144 (calculated); 335.1150 (observed).

[0297] Characterisation IR neat v.sub.max/cm.sup.−1: 2363, 2340, 1679, 1625, 1603, 1460, 1275.

1.3 Preparation of 4-((3-amino-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile

[0298] In a 25 mL bicol, the nitro compound is added to an ethanol/water mixture [8/2]. The reaction medium is heated to 80° C. and solid iron (10 equivalents) and 3 drops of HCl are added to the reaction medium. The whole mixture is heated to 80° C., under agitation, until the nitro compound is completely reduced.

[0299] The crude reaction mixture is cooled to ambient temperature and filtered on filtre paper. The filtrate is concentrated and purified by means of chromatography on a silica column and the reduced product is thus obtained.

[0300] The 4-((3-amino-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile is obtained in solid form with a yield of 62%.

[0301] The melting temperature measured is 84.9-92.6° C.

[0302] Characterisation .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 7.98 (d, J=8.4 Hz, 1H); 7.59 (t, J=9.2 Hz, 2H); 7.26 (d, J=8.3 Hz, 1H); 6.68 (d, J=8.5 Hz, 1H); 6.46 (d, J=2.5 Hz, 1H); 6.36 (dd, J=8.5 Hz, J=2.5 Hz, 1H); 3.88 (s, 2H); 3.84 (s, 3H); 3.42 (s, 3H).

[0303] Characterisation .sup.13C NMR (75 MHz, CDCl.sub.3) δ: 154.5; 149.7; 144.9; 143.5; 137.5; 134.0; 130.1; 129.9; 126.7; 125.6; 123.0; 118.2; 113.6; 111.0; 110.9; 110.7; 55.7; 43.8.

[0304] Characterisation HRMS C.sub.18H.sub.17N.sub.4O: 305.1402 (calculated); 305.1399 (observed).

[0305] Characterisation IR neat v.sub.max/cm.sup.−1: 3475, 3377, 2960, 2837, 2236, 1570, 1502, 1264.

[0306] Characterisation (liquid chromatography/mass spectrometry) LC-MS: t.r. 15.36.

[0307] Purity: 95.47%.

Example 2: Preparation of 4-(3-iodo-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile

2.1 Preparation of 4-(3-iodo-4-methoxyphenyl)amino)quinoline-2-carbonitrile

[0308] ##STR00047##

[0309] In a sealed tube the following are mixed: 4-chloroquinoline-2-carbonitrile (376 mg, 2.00 mmol, 1 equivalent), and 3-iodo-4-methoxyaniline (500 mg, 2.00 mmol), dioxane (10 mL) and concentrated HCl (5 drops).

[0310] The mixture is heated overnight at 140° C.

[0311] After the reaction medium has cooled, the mixture is neutralised to neutral pH and extracted with ethyl acetate. The organic phases are dried over MgSO.sub.4.

[0312] The crude residue is purified by means of chromatography on silica gel (cyclohexane:ethyl acetate 0.fwdarw.30%) The 4-(3-iodo-4-methoxyphenyl)amino)quinoline-2-carbonitrile is isolated in the form of a yellow solid with a yield of 51%.

[0313] Characterisation .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 8.11 (d, J=8.5 Hz, 1H); 7.92 (d, J=7.7 Hz, 1H); 7.86-7.74 (m, 2H); 7.71-7.60 (m, 1H); 7.33 (dd, J=8.3; 2.7 Hz, 1H); 7.00-6.88 (m, 2H); 6.73 (s, 1H); 3.98 (s, 3H).

[0314] Characterisation Electrospray Ionisation-High Resolution Mass Spectrometry (ESI.sup.+) HRMS: m/z for C.sub.17H.sub.13N.sub.3O [M+H].sup.+ 402.0103 (calculated); 402.0113 (found).

2.2 Preparation of 4-((3-iodo-4-methoxyphenyl)(methyl)amino)quinoline-2-carbonitrile

[0315] ##STR00048##

[0316] NaH (70.0 mg, 2.17 mmol) is added to a solution of 4-((3-iodo-4-methoxyphenyl)amino)quinoline-2-carbonitrile (219 mg, 0.54 mmol) in Dimethylformamide (DMF) (5 mL) at 0° C. CH.sub.3I (305 mg, 2.17 mmol) is then added drop by drop. The mixture is agitated for a period of 30 minutes at 0° C.

[0317] The mixture is brought to ambient temperature, diluted with water and then extracted with ethyl acetate and dried over MgSO.sub.4.

[0318] The crude residue is purified by means of chromatography on silica gel (cyclohexane:ethyl acetate 0.fwdarw.40%)

[0319] The compound 4-((3-iodo-4-methoxyphenyl)(methyl)amino)quinoline-2-carbonitrile is isolated in the form of a yellow solid with a yield of 71%.

[0320] Characterisation .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 8.08 (d, J=8.4 Hz, 1H); 7.79-7.51 (m, 3H); 7.48-7.21 (m, 2H); 6.92 (dd, J=8.7; 2.7 Hz, 1H); 6.73 (d, J=8.8 Hz, 1H); 3.88 (s, 3H); 3.48 (s, 3H).

[0321] Characterisation .sup.13 C NMR (75 MHz, CDCl.sub.3) δ: 155.49; 154.17; 149.84; 144.02; 134.25; 134.19; 130.56; 130.29; 127.41; 125.07; 124.27; 123.06; 117.91; 112.35; 111.28; 86.64; 56.66; 43.64.

[0322] Characterisation (ESI.sup.+) HRMS: m/z C.sub.18H.sub.15N.sub.3OI [M+H].sup.+ 416.02260 (calculated); 416.0267 (found).

[0323] Characterisation IR (neat): 1571, 1562, 1482, 1430, 1279, 1109, 808, 766, 713, 603 cm.sup.−1.

[0324] Melting point=175-180° C.

Example 3: Preparation of (E)-5-(5-((2-cyanoquinolin-4-yl)(methyl) amino)-2-methoxyphenyl)-N-hydroxypent-4-enamide

3.1 Preparation of N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-enamide

[0325] ##STR00049##

[0326] One equivalent of carboxylic acid is mixed with one equivalent of NHTHP in Dichloromethane (DCM). One equivalent of (Dicyclohexylcarbodiimide) DCC is subsequently added. The mixture is agitated overnight at ambient temperature and then washed with a saturated bicarbonate solution and water. The residue is purified by means of chromatography on silica gel (cyclohexane:ethyl acetate 1:1).

[0327] N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-enamide in the form of a white solid is obtained with a yield of 86%.

[0328] Characterisation .sup.1H NMR (300 MHz, DMSO) δ: 10.93 (s, 1H); 5.78 (dq, J=10.6; 6.6 Hz, 1H); 5.00 (dd, J=21.1; 13.7 Hz, 2H); 4.80 (s, 1H); 3.92 (m, 1H); 3.50 (m, 1H); 2.24 (m, 2H); 2.08 (m, 2H); 1.69-1.51 (m, 6H).

3.2 Preparation of (E)-5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-enamide

[0329] ##STR00050##

[0330] In a sealed tube purged with argon gas, the following are added: 4-((3-iodo-4-methoxyphenyl)(methyl)amino)quinoline-2-carbonitrile as prepared in Example 2 above (30.0 mg, 0.072 mmol), N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-enamide (42.0 mg, 0.20 mmol), tri(o-tolyl)phosphine (7.20 mg, 0.023 mmol), Pd(OAC).sub.2 (6.0 mg, 0.026 mmol), EtN.sub.3 (49.0 mg, 0.48 mmol) and DMF (1 mL); the mixture is degassed and heated overnight at 100° C.

[0331] The reaction medium is brought to ambient temperature, diluted with DCM and thereafter filtered through celite, the filtrate is then evaporated. The formation of the intermediate compound (see schematic above) is confirmed by Liquid Chromatography/Mass Spectrometry (LC/MS), and the compound is used in the subsequent step without purification.

[0332] A solution of 4N HCl in dioxane (0.5 mL) is added to a solution of the intermediate compound (see schematic above) in anhydrous dioxane (1 mL). The mixture is agitated for a period of 30 minutes at ambient temperature and subsequently evaporated at ambient temperature and then purified by high performance liquid chromatography (HPLC) using a gradient of acetonitrile in water. After lyophilisation, the compound (E)-5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-enamide is obtained in the form of a yellow solid with a yield of 30%.

[0333] Characterisation (ESI.sup.+) HRMS: m/z C.sub.23H.sub.23N.sub.4O.sub.3 [M+H].sup.+: 403.1770 (calculated); 403.1768 (found).

[0334] Characterisation IR (neat): 2947, 1641, 1569, 1491, 1235, 1031, 970, 758 cm.sup.−1.

[0335] Purity (HPLC): 100%.

[0336] Characterisation .sup.1H NMR (400 MHz, MeOD) δ: 7.89 (d, J=8.3 Hz, 1H); 7.61 (t, J=7.4 Hz, 1H); 7.53-4.45 (m, 1H); 7.34 (m, 1H); 7.24-7.23 (m, 3H); 6.87 (m, 3H); 6.67 (d, J=15.9 Hz, 1H); 6.17-6.04 (m, 1H); 3.81 (s, 3H); 3.48 (s, 4H); 2.46 (dd, J=13.5; 6.7 Hz, 2H); 2.28-2.16 (m, 2H).

[0337] Characterisation .sup.13C NMR (101 MHz, MeOD) δ: 172.04; 156.07; 155.65; 150.60; 144.35; 134.94; 131.31; 131.22; 130.31; 129.22; 127.66; 126.91; 126.25; 125.32; 123.70; 123.63; 118.85; 113.20; 111.66; 56.24; 44.45; 33.52; 30.33.

[0338] Melting point=177-182° C.

Example 4: Preparation of 5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-ynamide

4.1 Preparation of N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-ynamide

[0339] ##STR00051##

[0340] One equivalent of carboxylic acid is mixed with one equivalent of NHTHP in DCM. One equivalent of (Dicyclohexylcarbodiimide) DCC is subsequently added. The mixture is agitated overnight at ambient temperature and then washed with a saturated bicarbonate solution and water. The residue is purified by means of chromatography on silica gel (cyclohexane:ethyl acetate 1:1).

[0341] The N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-ynamide in the form of a white solid is obtained with a yield of 76%.

[0342] Characterisation .sup.1H RMN (300 MHz, DMSO) δ: 11.04 (s, 1H); 4.80 (s, 1H); 3.91 (s, 1H); 3.50 (d, J=11.6 Hz, 1H); 2.80 (s, 1H); 2.35 (d, J=6.2 Hz, 2H); 2.18 (t, J=7.0 Hz, 2H); 1.58 (m, 6H).

4.2 Preparation of 5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-ynamide

[0343] ##STR00052##

[0344] In a sealed tube purged with argon, the following are are added: 4-((3-iodo-4-methoxyphenyl)(methyl)amino)quinoline-2-carbonitrile as prepared in Example 2 above (30.0 mg, 0.072 mmol), N-((tetrahydro-2H-pyran-2-yl)oxy)pent-4-ynamide (28.0 mg, 0.144 mmol), PdCl.sub.2P(Ph.sub.3).sub.2 (12 mg, 0.017 mmol), CuI (7 mg, 0.036 mmol), Et.sub.3 N (21.0 mg, 0.22 mmol) and DMF (1 mL).

[0345] The mixture is degassed and agitated overnight at ambient temperature. The reaction mixture is diluted with DCM and thereafter filtered through celite, the filtrate is then evaporated. The formation of the intermediate compound (see scheme above) is confirmed by Liquid Chromatography/Mass Spectrometry (LC/MS), and the compound is used in the subsequent step without purification.

[0346] A solution of 4N HCl in dioxane (0.5 mL) is added to a solution of the intermediate compound (see schematic above) (29.0 mg, 0.06 mmol) in anhydrous dioxane (1 mL). The mixture is agitated for a period of 30 minutes at ambient temperature and subsequently evaporated at ambient temperature and then purified by high performance liquid chromatography (HPLC) using a gradient of acetonitrile in water.

[0347] After lyophilisation, the compound 5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-ynamide is obtained in the form of a yellow solid with a yield of 15%.

[0348] Characterisation .sup.1H NMR (400 MHz, MeOD) δ: 8.54 (s, 1H); 7.93 (d, J=8.3 Hz, 1H); 7.72-7.49 (m, 2H); 7.30-7.27 (m, 2H); 7.18-6.85 (m, 3H); 3.83 (s, 3H); 3.47 (s, 3H); 2.70 (s, 2H); 2.34 (s, 2H).

[0349] Characterisation .sup.13 C NMR (101 MHz, DMSO) δ: 167.20; 156.84; 153.86; 149.09; 142.69; 133.65; 130.27; 129.92; 128.30; 127.21; 125.14; 125.05; 122.31; 118.06; 113.16; 112.43; 112.11; 94.05; 76.58; 55.84; 43.65; 40.15; 39.94; 39.73; 39.52; 39.31; 39.10; 38.89; 31.49; 15.41.

[0350] Characterisation (ESI.sup.+) HRMS: m/z C.sub.23H.sub.21N.sub.4O.sub.3 [M+H].sup.+ 403.1614 (calculated); 403.1621 (found).

[0351] Characterisation IR (neat): 2987, 1644, 1496, 1066, 766 cm.sup.−1.

[0352] Purity (HPLC): 100%.

[0353] Melting point=170-175° C.

Example 5: Preparation of (E)-3-(5-((2-cyanoquinolin-4-yl)(methyl) amino)-2-methoxyphenyl)-N-hydroxyacrylamide

5.1 Preparation of N-((tetrahydro-2H-pyran-2-yl)oxy)acrylamide

[0354] ##STR00053##

[0355] One equivalent of carboxylic acid is mixed with one equivalent of NHTHP in DCM. One equivalent of (Dicyclohexylcarbodiimide) DCC is subsequently added. The mixture is agitated overnight at ambient temperature and then washed with a saturated bicarbonate solution and water. The residue is purified by chromatography on silica gel (cyclohexane:ethyl acetate 1:1).

[0356] The N-((tetrahydro-2H-pyran-2-yl)oxy)acrylamide is obtained in the form of a white solid with a yield of 61%.

[0357] Characterisation .sup.1H NMR (200 MHz, CDCL) δ: 9.41 (s, 1H); 6.40 (d, J=16.7 Hz, 1H); 6.15 (s, 1H); 5.69 (d, J=10.4 Hz, 1H); 4.97 (s, 1H); 3.96 (t, J=8.1 Hz, 1H); 3.59 (dd, J=11.3; 4.0 Hz, 1H); 1.77 (d, J=10.9 Hz, 3H); 1.58 (s, 3H).

5.2 Preparation of (E)-3-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxyacrylamide

[0358] ##STR00054##

[0359] In a sealed tube purged with argon, the following are added: 4-((3-iodo-4-methoxyphenyl)(methyl)amino)quinoline-2-carbonitrile as prepared in Example 2 above (30.0 mg, 0.072 mmol), N-((tetrahydro-2H-pyran-2-yl)oxy)acrylamide (34.0 mg, 0.20 mmol), tri(o-tolyl)phosphine (7.20 mg, 0.023 mmol), Pd(OAC).sub.2 (6.0 mg, 0.026 mmol), EtN.sub.3 (49.0 mg, 0.48 mmol) and DMF (I mL). The mixture is degassed and heated overnight at 100° C.

[0360] The reaction medium is brought to ambient temperature, diluted with DCM and thereafter filtered through celite, the filtrate is then evaporated. The formation of the intermediate compound (see schematic above) is confirmed by Liquid Chromatography/Mass Spectrometry (LC/MS), and the compound is used in the subsequent step without purification

[0361] A solution of 4N HCl in dioxane (0.5 mL) is added to a solution of the intermediate compound (see schematic above) in anhydrous dioxane (1 mL). The mixture is agitated for a period of 30 minutes at ambient temperature and subsequently evaporated at ambient temperature and then purified by high performance liquid chromatography (HPLC) using a gradient of acetonitrile in water.

[0362] After lyophilisation, the compound (E)-3-(5-((2-cyanoquinolin-4-yl)(methyl) amino)-2-methoxyphenyl)-N-hydroxyacrylamide is obtained in the form of a yellow solid with a yield of 55%.

[0363] Characterisation .sup.1H NMR (300 MHz, MeOD) δ: 7.94 (d, J=8.2 Hz, 1H); 7.82-7.48 (m, 3H); 7.44 (s, 1H); 7.29 (s, 2H); 7.07 (dd, J=29.0; 8.9 Hz, 2H); 6.42 (d, J=17.0 Hz, 1H); 4.85 (peak corresponding to hydrochloride salt overlapped with water), 3.90 (s, 3H); 3.53 (s, 3H).

[0364] Characterisation .sup.13 C NMR (75 MHz, MeOD) δ: 165.03; 155.74; 154.66; 149.31; 143.14; 134.58; 133.72; 130.06; 129.10; 126.58; 125.39; 124.73; 123.80; 122.40; 118.50; 117.41; 112.46; 110.98; 55.02; 42.86.

[0365] Characterisation (ESI.sup.+) HRMS: m/z C.sub.21H.sub.19N.sub.4O.sub.3 [M+H].sup.+ 375.1457 (calculated); 375.1455 (found).

[0366] Characterisation IR (neat): 3213, 1567, 1492, 1427, 1241, 1105, 977, 762 cm.sup.−1. Purity (HPLC): 100%.

[0367] Melting point=215-210° C.

Example 6: Comparison of the Antiproliferative Activity of Compounds of the Invention (Referenced as “ICQN”) in Free, Unconjugated Format on Cancer Cell Lines

[0368] The IC.sub.50 (as per accepted terminology) activities of the compounds according to the invention 4-((3-amino-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile (ICQN-1); 5-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxypent-4-ynamide (ICQN-2); and (E)-3-(5-((2-cyanoquinolin-4-yl)(methyl)amino)-2-methoxyphenyl)-N-hydroxyacrylamide (ICQN-3) were compared with compounds of the prior art and with a commercial and clinical reference compound, in particular MMAE (monomethylauristatin E). The IC.sub.50 activities were measured on various different cancer cell lines HCT116 (colorectal tumour), A549 (non-small cell lung cancer), NCI-N87 (gastric tumour), Mia-Paca-2 (pancreatic tumour), K562R (chronic myeloid leukemia), SKOV3 (ovarian tumour), SKBr3 (breast tumour, Her2 overexpression), MCF7 (breast tumour) and MDA-MB231 (breast tumour).

[0369] The cancer cell lines were obtained from the American Culture Collection (ATCC, Rockville, Md.) or from the German collection of microorganisms and cell cultures of the Leibniz Institute (DSMZ, Braunschweig-Germany) or from the European collection of cell cultures (ECACC, England). The cancer cell lines were cultured according to the supplier's instructions.

[0370] The HCT-116 human colorectal carcinoma, SK-BR3 breast carcinoma, and SK-OV-3 ovarian carcinoma cells were cultured in Gibco McCoy's 5A medium supplemented with 10% foetal calf serum (FCS) and 1% glutamine.

[0371] The A549 lung carcinoma cells, K562R myeloid leukemia cells, and the NCI-N87 gastric carcinoma cells were cultured in Gibco Roswell Park Memorial Institute (RPMI) 1640 medium supplemented with 10% foetal calf serum (FCS) and 1% glutamine. The Mia-Paca2 carcinoma cells were cultured in Gibco Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% foetal calf serum (FCS) and 1% glutamine.

[0372] The breast adenocarcinoma cells MDA-MB231 and MCF7 were cultured in Gibco RPMI 1640 culture medium supplemented with 10% foetal calf serum (FCS) and 1% glutamine. The cells were counted using a Vi-cell XR (Beckman Coulter) and the cell viability was assessed by using 0.25% trypan blue dye exclusion assay. The cells were tested for the presence of mycoplasmas prior to the experiments with the Mycoplasma PCR detection kit (Applied Biological Materials Inc., Canada) according to the manufacturer's instructions, and only Mycoplasma-free cells were used for the study. The cell lines were maintained at 37° C. in a humidified atmosphere containing 5% CO.sub.2.

[0373] For the determination of IC.sub.50, the cells were seeded in 96-well plates (3×10.sup.3 cells/well) containing 100 μl of growth medium. After 24 hours of culturing, the cells were treated with the tested compounds at 10 different final concentrations. Each concentration was obtained from serial dilutions in culture medium starting from the stock solution. The control cells were treated with the carrier. The experiments were carried out in triplicate.

[0374] The measurements were performed after 72 hours of treatment using the CellTiter Glo assay (Promega) which makes it possible to measure through bioluminescence (quantification of adenosine triphosphate—ATP) the number of living cells, by using a PolarStar Omega microplate reader (BMG-Labtech).

[0375] The dose-response curves were plotted with the Graph Prism software application and the IC.sub.50 values were calculated using the Graph Prism software based on polynomial curves (four or five parameter logistic equations).

[0376] The results are shown in Table 1 below.

[0377] As these results show, the compounds according to the invention exhibit very good inhibitory activity against a number of cancer cell lines.

TABLE-US-00001 TABLE 1 Mia- MDA- HCT116 A549 NIC-N87 Paca-2 K562R SKOV3 SKBr3 MCF7 MB231 IC.sub.50 IC.sub.50 IC.sub.50 IC.sub.50 IC.sub.50 IC.sub.50 IC.sub.50 CI.sub.50 CI.sub.50 Cell Lines (nM) (nM) (nM) (nM) (nM) (nM) (nM) (nM) (nM) 4-((3-amino-4-methoxyphenyl) 0.23 0.72 0.30 0.49 0.47 0.44 0.36 0.17 0.34 (methyl)amino)quinoline- 2-carbonitrile ICQN-1 MMAE (GOLD STANDARD) 1.52 4.12 6.58 3.02 19.70 0.08 0.06 0.58 1.25 4-((3-amino-4-ethoxyphenyl) / / 0.93 0.29 0.36 0.59 0.38 / / (methyl)amino)quinoline- 2-carbonitrile ICQN-2 (E)-3-(5-((2-cyanoquinolin-4- / / 0.10 0.94 0.56 2.64 1.78 0.78 0.44 yl)(methyl)amino)-2-methoxyphenyl)-N- hydroxyacrylamide ICQN-3

[0378] The results of IC.sub.50 over the cell lines HCT116, A549, NCI-N87, Mia-Paca-2, K562R, MCF7 and MDA-MB231 are overall far better than those obtained with the commercial and clinical reference compound MMAE. It should be reiterated that the selection of cell lines is based on a broad spectrum of solid and liquid cancer indications representing a medical need that remains unmet in which context the conjugated antibodies would be relevant. This cytotoxicity observed over a broad panel is also a criterion of commercial success for payloads.

Example 7: Comparative Analysis of the Antiproliferative Activity of the Compounds of the Invention with the Commercial and Clinical Reference Compound MMAE (in Unconjugated Format)

[0379] The IC.sub.50 ratio was established between a compound of the invention (ICQN-1) and MMAE. The higher the IC.sub.50 ratio, the greater the potential for therapeutic improvement and thus greater the potential for commercial success.

TABLE-US-00002 TABLE 2 NCI- Mia- MDA- Cell Lines HCT116 A549 N87 Paca-2 MCF7 MB231 IC.sub.50 Ratio 7 6 22 6 3 4 ICQN1/MMAE

[0380] Thus, the compounds according to the invention demonstrate a very significant advantage over MMAE. For example, in the context of the NCI-N87 (gastric cancer) cell line, ICQN1 is 22 times more efficacious than MMAE.

Example 8: Antiproliferative Activity as Compared to the Compounds of the Prior Art Having a Quinoline Nucleus and an Aromatic Ring Linked to Each Other by an N-Me Group (L. Chen et al. Eur. J. Med. Chem. 2017, 138, 1114)

[0381] In the context of the work published by Chen et al. cited above, among the molecules mentioned, the compound 13b has the following structure:

##STR00055##

[0382] This compound 13b shows an IC.sub.50 of 3.2 nM over the MDA-MB-231 cell line.

[0383] Table 3 below presents the collective comparative data over 7 cell lines for a compound according to the invention (ICQN-1 (4-((3-amino-4-methoxyphenyl)(methyl)amino) quinoline-2-carbonitrile)) and for the compound 13b described by L. Chen et al. (Eur. J. Med. Chem. 2017, 138, 1114)

TABLE-US-00003 TABLE 3 Mia- HCT116 A549 NCI-N87 Paca2 K562R SKOV3 SKBr3 Prior Art 2.15 0.68 4.36 0.92 3.59 1.28 2.17 Compound 13b according to L. Chen et al. Compound 0.23 0.72 0.30 0.49 0.47 0.44 0.36 according to the invention (Compound ICQN1) Ratio of activity ~10 1 15 2 8 3 6 13b vs ICQN-1

[0384] The compounds of the invention, quite surprisingly, have an overall cytotoxic activity that is far greater than that of the compound 13b. The resulting activity obtained following the replacement of the Me group by CN at position 2 of the quinoline is unexpected and could not have been predicted by the person skilled in the art. In fact, according to L. Chen et al as well as the person skilled in the art, the methyl at position 2 of quinoline was considered to be necessary in order to maintain the inhibitory activity. Moreover, according to L. Chen et al, no mention is made of any conjugation or application in the context of an ADC strategy.

Example 9: Antiproliferative Activity as Compared to the Compounds of the Prior Art Having a Diheteroarylmethylamine Type Structure (Alami et al.)

[0385] According to Alami et al. Eur. J. Med. Chem. 2019, 168, 176-188, by comparison of the molecules Ia and Ib (structures here below), the person skilled in the art noted that replacing Me by CN at position 2 of quinoline led to a drastic drop in cytotoxic activity (by a factor of 170 over the HCT116 cell line).

##STR00056##

[0386] However, as supported by Example 8 here above, the replacement of an Me by CN at position 2 of quinoline induces a surprising improvement in cytotoxicity (by a factor of 10). The person skilled in the art did not expect and could not have foreseen such activity in respect of the compounds according to the present invention.

[0387] It should also be noted that the compound 1a according to Alami et al. could not possibly be considered as a payload in the context of an ADC strategy given that it does not have an anchor point for binding to a linker.

Example 10: Antiproliferative Activity as Compared to the Compounds of the Prior Art Having a Di(heteroaryl)arylethylene Type Structure

[0388] According to Alami et al. J. Med. Chem. 2019, 62, 1902-1916, by comparing two at a time the molecules 4f/4j and 4g/4k that carry a double bond instead of the N-Me group, the person skilled in the art would have found that replacing Me with CN at position 2 of quinoline did not provide the ability to foresee achieving an improvement in the cytotoxic activity IC.sub.50 below 1 nM for the cell line HCT116. The person skilled in the art noted a loss in activity when passing from the compound 4f (Me at position 2) to the compound 4j (CN at position 2).

TABLE-US-00004 TABLE 4 IC.sub.50 (HCT116) nM [00057] 2 [00058] 12 [00059] 5.7 [00060] 3.4

Example 11: Comparative Analysis of the Antiproliferative Activity of a Compound of the Invention as Compared to the Payload of the Prior Art ICQO-1

[0389] Of all the compounds identified in the prior art, ICQO-I is the only one to exhibit the characteristic of a payload according to the person skilled in the art. ICQO is a compound disclosed in the international patent application PCT/EP2018/058168 as having the following structure:

##STR00061##

[0390] The IC.sub.50 ratio was established between a compound of the invention (ICQN-1) and the compound of the prior art ICQO-1. The higher the ratio, the greater the potential therapeutic activity in vivo.

TABLE-US-00005 TABLE 5 Cell lines HCT-116 SKOV-3 ICQN-1 vs ICQO-1 44 3

[0391] The ratios indicate that the compounds of the invention (ICQN) demonstrate a very significant advantage over compounds of the ICQO-1 type. For example, in the context of the HCT-116 (colorectal cancer) cell line, ICQN-1 is 44 times more efficacious than the payload compound ICQO-1. This significant difference was particularly unforeseeable and unexpected for the person skilled in the art.

Example 12: Comparative Analysis of the Antiproliferative Activity of ICQN as Compared to Compounds of the Prior Art of the Quinoline Type (Patent Application US 2006/074187, Example 21)

[0392] VB118 is a quinoline compound (patent application US 2006/074187, Example 21) that has been synthesised and described with a view to being compared with the compounds according to the invention.

TABLE-US-00006 TABLE 6 Cell Lines ICQN2 ICQN1 VB118 NCI-N87 0.93 0.30 >100 nM Mia-Paca-2 0.29 0.49 >100 nM K562R 0.36 0.47 >100 nM SKOV-3 0.59 0.44 >100 nM SKBR3 0.38 0.36 >100 nM

[0393] The addition of the nitrile function and the amine function —NH2 at position 2 of quinoline on the compounds according to the invention (ICQN), compared with the compounds of the prior art of the VB118 type, induces a surprising increase, greater by at least 2 log of activity, over a broad panel of cell lines and cancer indications.

Example 13: Comparative Analysis of the Antiproliferative Activity of the Compounds of the Invention (ICQN) as Compared to the Commercial Reference Compound MMAE and the Payload ICQO-1 on Resistant Cancer Cells (MDR Profile: Multi Drug Resistance)

[0394] The K562R (chronic myeloid leukemia) cells have an MDR profile that allows them to be resistant to several chemotherapeutic compounds including the reference compound MMAE.

TABLE-US-00007 TABLE 7 K562R (PgP+) Ratio vs MMAE Ratio vs ICQO-1 MMAE .sup. 35 nM ICQO-1 1.98 nM 17 ICQN-1 0.47 nM 74 4.2

[0395] The person skilled in the art within the payloads and conjugated medicinal products field would note that a payload such as MMAE with an IC.sub.50 of 35 nM offers lower therapeutic interest than a compound according to the invention. A payload, in order to be efficacious once conjugated, preferably has sub-nanomolar activity on the targeted cancer line. It is found that the compound according to the invention ICQN-1 exhibits a superiority that is not only 74 times greater than the MMAE but also 4.2 times greater than the compound ICQO-1. The compounds according to the invention exhibit a particularly surprising activity while also exhibiting therapeutic differentiation for cancers that have a multi-drug resistance (MDR) profile.

Example 14: Preparation of Conjugated Antibodies

[0396] Various different “Toxic-Linker” compounds (based on valine-citrulin), enzyme cleavable (by Cathepsin B enzyme) and non-cleavable, were obtained as illustrated in table 8 below:

TABLE-US-00008 TABLE 8 Mal-Val-Cit- PABC-ICQN-1 (cleavable) (VB179) [00062] Mal-Val-Cit- PABC-ICQO-1 (VB185) [00063] Mal-PEG4-Val- Cit-PABC- ICQN-1 (VB199) [00064] Mal-PEG4-Val- Cit-PABC- ICQO-1 (VB279 & VB288) [00065] Mal-Val-Cit- PABC-NI313 (VB277) [00066] Mal-ICQN-1 (non cleavable) (VB284) [00067] MCC-ICQN-1 (non cleavable) (VB289) [00068]

[0397] The compounds VB179, VB185, VB199 and VB279 were obtained by activation of the NH2 function of the compounds having the formula (I) according to the invention (ICQN-1) by para-nitrophenyl chloroformate. The intermediary formed then reacts with the benzyl alcohol function of the linker MC-Val-Cit-PABA.

[0398] The compound VB277 was prepared by activation of the benzyl alcohol function of the linker MC-Val-Cit-PABA in triflate form and followed by reacting in basic medium with the compound NI313.

[0399] The compounds VB284 and VB289 were prepared by peptide coupling between ICQN-1 and an acid function.

[0400] VB179:

[0401] .sup.1H NMR (400 MHz, DMSO-de) 5:8.58 (s, 1H), 8.06 (d, J=7.3 Hz, 1H), 7.96 (d, J=7.8 Hz, 1H), 7.79 (d, J=8.4 Hz, 1H), 7.67 (t, J=7.6 Hz, 1H), 7.60 (s, 1H), 7.58 (s, 2H), 7.56 (s, 1H), 7.49 (dd, J=8.6, 1.1 Hz, 1H), 7.34 (m, 1H), 7.31 (s, 1H), 6.98 (s, 2H), 6.94 (d, J=8.8 Hz, 1H), 6.74 (dd, J=8.7, 2.7 Hz, 1H), 5.97 (t, J=5.8 Hz, 1H), 5.40 (s, 2H), 5.00 (s, 2H), 4.38 (td, J=8.2, 5.5 Hz, 1H), 4.18 (dd, J=8.3, 7.1 Hz, 1H), 3.77 (s, 3H), 3.43 (s, 3H), 2.97 (m, 2H), 2.15 (m, 2H), 1.97 (dq, J=13.5, 6.7 Hz, 1H), 1.70 (m, 1H), 1.57 (m, 1H), 1.52-1.47 (m, 2H), 1.45 (d, J=7.3 Hz, 2H), 1.42-1.30 (m, 2H), 1.23-1.14 (m, 2H), 0.85 (d, J=6.7 Hz, 3H), 0.82 (d, J=6.7 Hz, 3H). HRMS (ESI): m/z [M+H] calcd. for C.sub.47H.sub.55N.sub.10O.sub.9: 903.4153 Found: 903.4156. Purity: 98.2%

[0402] VB 199:

[0403] .sup.1H NMR (400 MHz, DMSO-d.sub.6) δ: 8.58 (s, 1H), 8.06 (d, J=7.3 Hz, 1H), 7.96 (d, J=7.8 Hz, 1H), 7.79 (d, J=8.4 Hz, 1H), 7.67 (t, J=7.6 Hz, 1H), 7.60 (s, 1H), 7.58 (s, 2H), 7.56 (s, 1H), 7.49 (dd, J=8.6, 1.1 Hz, 1H), 7.34 (m, 1H), 7.31 (s, 1H), 6.98 (s, 2H), 6.94 (d, J=8.8 Hz, 1H), 6.74 (dd, J=8.7, 2.7 Hz, 1H), 5.97 (t, J=5.8 Hz, 1H), 5.40 (s, 2H), 5.00 (s, 2H), 4.38 (td, J=8.2, 5.5 Hz, 1H), 4.18 (dd, J=8.3, 7.1 Hz, 1H), 3.77 (s, 3H), 3.62-3.47 (m, 10 2H), 3.43 (s, 3H), 2.97 (m, 2H), 1.97 (dq, J=13.5, 6.7 Hz, 1H), 1.70 (m, 1H), 1.57 (m, 1H), 1.42-1.30 (m, 2H), 0.85 (d, J=6.7 Hz, 3H), 0.82 (d, J=6.7 Hz, 3H). HRMS (ESI): m/z [M+H] calcd. for C.sub.52H.sub.65N.sub.10O.sub.13: 1037.4733 Found: 1037.4727. Purity: 96.0%

[0404] VB277

[0405] HRMS (ESI): m/z [M+H] calcd. for C.sub.49H.sub.57N.sub.10O: 929.4310 Found: 929.4312.

[0406] VB284

[0407] .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 8.48 (d, J=1.9 Hz, 1H), 8.04 (d, J=9.1 Hz, 1H), 7.83 (s, 1H), 7.73-7.55 (m, 2H), 7.21 (s, 1H), 6.74 (d, J=8.7 Hz, 1H), 6.71 (s, 2H), 6.53 (d, J=9.6 Hz, 1H), 3.90 (s, 2H), 3.57 (m, 2H), 3.53 (s, 3H), 2.43 (t, J=7.3 Hz, 2H), 1.76 (m, 4H), 1.42 (m, 2H). HRMS (ESI): m/z [M+H] calcd. for C.sub.28H.sub.28N.sub.5O.sub.4: 498.2141 Found: 498.2140. Purity: 100%

[0408] VB289

[0409] .sup.1H NMR (300 MHz, CDCl.sub.3) δ: 8.46 (d, J=2.3 Hz, 1H), 8.02 (d, J=8.8 Hz, 1H), 7.86 (s, 1H), 7.70-7.54 (m, 2H), 7.34-7.23 (m, 1H), 7.18 (s, 1H), 6.71 (s, 2H), 6.45 (dd, J=8.6, 2.5 Hz, 1H), 3.87 (s, 3H), 3.46 (s, 3H), 3.40 (d, J=6.6 Hz, 2H), 2.30-2.16 (m, 1H), 2.10-1.97 (m, 2H), 1.87-1.76 (m, 2H), 1.54 (ddd, J=25.0, 13.1, 3.0 Hz, 2H), 1.16-0.98 (m, 2H), 0.88 (m, 1H). HRMS (ESI): m/z [M+H] calcd. for 524.2298 C.sub.30H.sub.30N.sub.5O.sub.4: Found: 524.2300. Purity: 93%

[0410] The conjugated antibodies are obtained according to the protocol described in Example 9 of the international patent application PCT/EP2018/058168, incorporated herein by reference (in particular paragraph 158), if necessary adapted to the reading of the present invention and the general knowledge of the person skilled in the art.

Example 15: Evaluation of the Activity of the Conjugated Antibodies Obtained

[0411] A compound according to the invention (ICQN-1) was coupled to different linkers and subsequently the toxic linkers were conjugated to the antibody Trastuzumab with a view to obtaining different ADCs. Among the ADCs prepared, the following ADC Trastuzumab-Mal-PEG4-Val-Cit-PABC-ICQN-1 with DAR 4 showed in vitro nanomolar activity on the gastric carcinoma cell line NCI-N87 (IC.sub.50=9 nM). By way of comparison, the reference ADC with the reference payload MMAE: Trastuzumab-Mal-Val-Cit-PABC-MMAE showed almost equivalent cytotoxic activity (IC.sub.50 of 6 nM).