The present invention relates to inhibitors of ras farnesylation of the Formula I ##STR1##

wherein:

• R¹ is for example H and further values as defined in the specification; R² is for example H and further values as defined in the specification; R³ is for example H or a substituent having values as defined in the specification; p is 0-3 in which R³ values can be the same or different; L is a linking moiety for example —CH_2—NH— and further values as defined in the specification; A is selected from phenyl; naphthyl; a 5-10 membered monocyclic or bicyclic heteroaryl ring containing upto 5 heteroatoms where the heteroatoms are independently selected from O, N & S; or a —S—S— dimer thereof when R²H; or a N-oxide or a pharmaceutically-acceptable salt, prodrug or solvate thereof. Processes for their preparation their use as therapeutic agents and pharmaceutical compositions containing them.