Treating diabetes with dipeptidyl peptidase-iv inhibitors

A compound of structural Formula I:

• or a pharmaceutically acceptable salt thereof;
• wherein
• R1, R9, R10 and R11 are selected from the group consisting of halogen and hydrogen;
• X is selected from the group consisting of —NR4— and —CHR4—;
• Y is selected from the group consisting of —N— and —CHR2—;
• Z is selected from the group consisting of —N— and —CH—;
• R2 is selected from the group consisting of hydrogen or taken with R8 forms (CH2)n;
• R3 is selected from the group consisting of hydrogen, SO2NH2, SO2NH(C1-6alkyl), SO2N(C1-6alkyl)2, SO2NHC3-6 cycloalkyl, SOC1-6alkylNP, SO2NHP, SO2C1-6alkyl and SO2C3-6cycloalkyl, wherein Q is a amine protecting group;
• R4 is hydrogen or C1-6 alkyl or taken together with R6 forms a six-membered ring;
• R5 is hydrogen or C1-6 alkyl or taken together with R7 forms —(CH2)n-;
• R6 is hydrogen or C1-6 alkyl or taken together with R4 forms a six-membered ring;
• R7 is hydrogen or C1-6 alkyl or taken together with R5 forms —(CH2)n-;
• R8 is hydrogen or C1-6 alkyl or taken together with R2 forms —(CH2)n-, wherein when Y and X are CH2 and R3 is SO2C1-6alkyl or SO2C3-6cycloalkyl then R5, R6, R7 and R8 cannot be simultaneously hydrogen;
• and
• n is 1 or 2.