Blockade of voltage dependent sodium channels

A compound of formula (I), or a pharmaceutically acceptable salt thereof,

• wherein:
• R1 is substituted or unsubstituted benzyl;
• R2 is C6–C10 aryl, 5- to 10-membered heteroaryl, 3- to 6-membered heterocyclyl, C3–C6 carbocyclyl or —XR wherein X is a divalent C1–C6 alkyl, C2–C6 alkenyl or C2–C6 alkynyl group and R is C6–C10 aryl, 5- to 10-membered heteroaryl, 3- to 6-membered heterocyclyl or C3–C6 carbocyclyl, or R2 is C1–C6 alkyl, C2–C6 alkenyl, C2–C6 alkynyl or —COR, wherein R is selected from C1–C6 alkyl, C6–C10 aryl a 5- to 10-membered heteroaryl, provided that R2 is not a furanyl, phenyl, pyrrolyl, or thienyl group;
• and
• either R3 and R4, together with the carbon atoms to which they are attached, form a phenyl group, or R3 is hydrogen an R4 is 5- to 10-membered heteroaryl, —CONR′—NR″COR, —CONR′—NR″CS—R, —CONR′R″, —CONR′—NR″CO—NR′″R″″ or —CONR′—NR″CS—NR′″R″″, wherein each R is the same or different and is selected from C1–C6 alkyl, C6–C10 aryl, —(C1–C6 alkyl)-(C6–C10 aryl) and 5- to 10-membered heteroaryl and each R′, R″, R′″ and R″″ is the same or different and is selected from hydrogen, C1–C6 alkyl, C6–C10 aryl, —(C1–C6 alkyl)-(C6–C10 aryl) and 5- to 10-membered heteroaryl,
• said aryl and heteroaryl groups and moieties being unsubstituted or substituted by 1, 2 or 3 substituents selected from halogen, hydroxyl, —SH, C1–C6 alkyl, C2–C6 alkenyl, C2–C6 alkynyl, C6–C10 aryl, 5- to 10-membered heteroaryl, 3- to 6-membered heterocyclyl, C3–C6 carbocyclyl, —XY wherein X is a divalent C1–C6 alkyl, C2–C6 alkenyl or C2–C6 alkynyl group and Y is a C6–C10 aryl or 5- to 10-membered heteroaryl group, nitro, cyano, C1–C6 alkoxy, C2–C6 alkenyloxy, C2–C6 alkynyloxy, C1–C6 alkylthio, C2–C6 alkenylthio, C2–C6 alkynylthio, —OR, —SR, —COR′, —CO2R″, —CONR′″R″″, —NR′″R″″, —NR″—CO—R′, —S—X—COR′, —O—X—COR′, —S—X—CO2R′, and —O—X—CO2R′, wherein R is C6–C10 aryl, 5- to 10-membered heteroaryl or —XY wherein X is a divalent C1–C6 alkyl, C2–C6 alkenyl or C2–C6 alkynyl group and Y is a C6–C10 aryl or 5- to 10-membered heteroaryl group, R′ is selected from R, C1–C6 alkyl, C2–C6 alkenyl and C2–C6 alkynyl, R″ is selected from R′ and hydrogen, R′″ and R″″ are the same or different and are selected from R′, hydrogen and hydroxy and R′is C1–C6 alkyl, C6–C10 aryl or 5- to 10-membered heteroaryl, the aryl, heteroaryl, carbocyclic and heterocyclic moieties in said substituents being unsubstituted or substituted by one or more further unsubstituted substituent selected from halogen, hydroxy, C1–C6 alkyl, C1–C6 haloalkyl, C1–C6 alkoxy, C1–C6 haloalkoxy and —NR′R″ wherein R′ and R″ are the same or different and represent hydrogen C1–C6 alkyl,
• said carbocyclic and heterocyclic groups being unsubstituted or substituted by up to 3 substituents selected from halogen, hydroxyl, —SH, C1–C6 alkyl, C2–C6 alkenyl, C2–C6 alkynyl, C6–C10 aryl, 5-to 10-membered heteroaryl, 3- to 6-membered heterocyclyl, C3–C6 carbocyclyl, nitro, cyano, C1–C6 alkoxy, C2–C6 alkenyloxy, C2–C6 alkynyloxy, C1–C6 alkylthio, C2–C6 alkenylthio, C2–C6 alkynylthio, —OR, —SR, —COR′, —CO2R″, —CONR′″R″″, —NR′″R″″, —S—X—COR′ and —O—X—COR′ wherein R is C6–C10 aryl, 5- to 10-membered heteroaryl or —XY wherein X is a divalent C1–C6 alkyl, C2–C6 alkenyl or C2–C6 alkynyl group and Y is a C6–C10 aryl or 5- to 10-membered heteroaryl group, R′ is selected from R, C1–C6 alkyl, C2–C6 alkenyl and C2–C6 alkynyl, R″ is selected from R′ and hydrogen, R′″ and R″″ are the same or different and are selected from R′, hydrogen and hydroxy and R′is C6–C10 aryl or 5- to 10-membered heteroaryl, the aryl, heteroaryl, carbocyclic and heterocyclic moieties in said substituent being unsubstituted or substituted by one or more further unsubstituted substituent selected from halogen, hydroxy, C1–C6 alkyl, C1–C6 haloalkyl, C1–C6 alkoxy, C1–C6 haloalkoxy and —NR′R″ wherein R′ and R″ are the same or different and represent hydrogen or C1–C6 alkyl,
• said alkenyl and alkynyl groups or moieties being unsubstituted or substituted by 1 or 2 substituents selected from halogen, cyano, nitro, hydroxy, C1–C6 alkoxy and
• —NR′R″ substituents, wherein R′ and R″ are the same or different and represent hydrogen or C1–C6 alkyl;
• and
• said alkyl groups and moieties being unsubstituted or substituted by 1 or 2 substituents selected from halogen, cyano, nitro, hydroxy, C1–C6 alkoxy and —NR′R″, wherein R′ and R″ are the same or different and represent hydrogen or C1–C6 alkyl, or by 1, 2 or 3 halogen substituents,
• provided that when R2 is —CONH—(C6–C10 aryl) or C1–C4 alkyl and R3 is hydrogen, R4 is not heteroaryl or a substituted or unsubstituted amide moiety.