Methods and compounds for producing dipeptidyl peptidase IV inhibitors and intermediates thereof

1. A compound of the structure of Formula IA:

or a pharmaceutically acceptable salt thereof, wherein

R 1 is OH;

R 2 is selected from the group consisting of —C(═O)—COR 4 , —C(X) n —COR 4 and

wherein

X is a halogen;

n is 2;

R 4 is selected from the group consisting of O-alkyl, NH 2 and OH; and

R 7 and R 8 are each selected from the group consisting of H and COOR 9 , wherein R 9 is alkyl; and

R 3 selected from the group consisting of H or OH.

2. The compound of claim 1 of the structure of Formula I,

3. The compound of claim 1 of the structure of Formula II,

4. The compound of claim 1 of the structure of Formula V,

5. The compound of claim 1 of the structure of Formula VI,

or its DABCO salt VIA

6. The compound of claim 1 of the structure of Formula VIII,

or the compound of the structure of Formula IX