Dipeptide nitriles

A compound of formula (I):

• wherein
• R is substituted aryl selected from 4-(morpholin-1-yl)-phen-1-yl, 4-(morpholin-1-yl-methyl)-phen-1-yl, 4-(pyrrolidin-1-yl-methyl)-phen-1-yl), 4-(4-methylpiperazin-1-yl)-phen-1-yl and 4-(piperidinyl)-phenyl;
• R2 and R3 are, independently, hydrogen or lower alkyl;
• or
• R2 and R3, together, represent lower alkylene, optionally interrupted by O, S or NR6, so as to form a ring with the carbon to which they are attached, and R6 is hydrogen, lower alkyl or aryl-lower alkyl;
• R4 and R5 are, independently, hydrogen or lower alkyl;
• or
• R4 and R5, together, represent lower alkylene, optionally interrupted by O, S or NR6, so as to form a ring with the carbon atom to which they are attached, and R6 is hydrogen, lower alkyl or aryl-lower alkyl;
• X1 is —C(O)—;
• Y is oxygen;
• and
• x is zero;
• or a pharmaceutically acceptable salt thereof.

A compound of formula (II):

• wherein
• R20 is substituted aryl selected from 4-(morpholin-1-yl)-phen-1-yl, 4-(morpholin-1-yl-methyl)-phen-1-yl, 4-(pyrrolidin-1-yl-methyl)-phen-1-yl), 4-(4-methylpiperazin-1-yl)-phen-1-yl and 4-(piperidinyl)-phenyl;
• R22 is hydrogen or lower alkyl and R23 is lower alkyl;
• or
• R22 and R23, together with the carbon atom to which they are attached, form a C5-C8 cycloalkyl group or a heterocycloalkyl group of 3-10 ring atoms;
• R24 and R25 are, independently, hydrogen or lower alkyl;
• or
• R24 and R25, together with the carbon atom to which they are attached, form a C3-C7 cycloalkyl group;
• X1 is —C(O)—;
• Y is oxygen;
• and
• x is zero;
• or a pharmaceutically acceptable salt thereof.

A compound of the formula (I):

• wherein
• R is phenyl substituted by hetero(C3-C10)cycloalkyl(C1-C4)alkyl or hetero(C3-C10)cycloalkyl;
• x is zero;
• X1 is —C(O)—;
• R2 is hydrogen or lower alkyl;
• R3 is lower alkyl;
• or
• R2 and R3 together represent lower alkylene optionally interrupted by O, S or NR6, wherein, so as to form a ring with the carbon atom to which they are attached, and R6 is hydrogen or lower alkyl;
• Y is oxygen;
• R4 and R5 are hydrogen;
• or a pharmaceutically acceptable salt thereof.