NK1 antagonists

A compound having the formula (I):

• or a pharmaceutically acceptable salt thereof, wherein
• Ar1 is phenyl, wherein said phenyl can be unsubstituted or substituted with 1 to 3 fluoro;
• Ar2 is bis(trifluoromethyl)phenyl;
• X1 is —O—;
• R1 and R2 are independently selected from the group consisting of H, C1-C6 alkyl or hydroxyl(C1-C3 alkyl), C3-C8 cycloalkyl, —CH2F, —CHF2, —CF3;
• R3 is H, C1-C6 alkyl, hydroxyl(C1-C3 alkyl), C3-C8 cycloalkyl, —CH2F, —CF2H, or —CF3;
• R6 and R7 are independently selected from H or C1-C6 alkyl;
• n2 is 1 or 2;
• R4 and R5 together are ═O;
• R18 is C1-C6 alkyl, Cbz or H;
• R32 and R33 are each H;
• or a diaseteromer, enantiomer, stereoisomer, regioisomer, rotamer, or tautomer thereof.