Thymoquinone derivatives for treatment of cancer

A compound of formula (I)

• or a pharmaceutically acceptable salt or solvate thereof, wherein
• R1 and R2 are selected from CH3 and isopropyl, wherein R1 and R2 are different;
• X is NR3R4, wherein:
• R3 is selected from H or —(CH2)2—OH;
• and
• R4 is selected from H or —(C1-C4alkyl)R5, wherein:
• R5 is selected from:
• a) —OH,
• b) phenyl substituted by 1-3 substituents independently selected from —CF3, —F, —OCH3, —NH2 and —SO2NH2,
• c) a 5 or 6 membered heterocyclic ring having 1 or 2 hetero atoms selected from O and N, and wherein the heterocyclic ring is optionally substituted by 1-2 substituents independently selected from —OH and CH3,
• d) a ring system having the formula of:
• and
• e) NR6R7, wherein:
• R6 is selected from H or CH3;
• and
• R7 is selected from CH3, phenyl, and a ring system having the formula of:
• wherein the ring system is optionally substituted by 1-2 substituent of CH3;
• and
• Y is H,
• wherein R3 and R4 are not both H.