Patent ID: 8304553

Claim:
A process of forming a 4,5-diamino cyclohexene carboxylate ester of general formula (1) or a pharmaceutically acceptable salt thereof, wherein R 1 -R 3 are independently selected from the group consisting of a silyl-group, an aliphatic group, an alicyclic group, an aromatic group, an arylaliphatic group, and an arylalicyclic group, comprising 0 to about 3 heteroatoms selected from the group N, O, S, Se and Si, wherein R 4 , R 11 and R 12 are independently selected from the group consisting of H, a silyl-group, and an aliphatic, alicyclic, aromatic, arylaliphatic, and arylalicyclic group, comprising 0 to about 3 heteroatoms selected from the group N, O, S, Se and Si, the process comprising: (a) reacting a 3,4-dihydropyran compound (9) wherein R 5 and R 6 are independently selected suitable protecting groups, and wherein the symbols indicates that the bond may have any configuration, to form an aldehyde of general formula (4) (b) oxidizing aldehyde (4) to carboxylic acid ester (10) (c) replacing protecting group R 5 of carboxylic acid ester (10) by an N-substituted carbamoyl group, thereby forming N-substituted carbamate (3) wherein R 7 is a suitable protecting group, (d) reacting N-substituted carbamate (3) to form oxazolinidone (12) (e) removing moiety OR 6 from oxazolinidone (12) to form oxazolinidone (13) wherein R 8 is H or one of a silyl-group, an aliphatic group, an alicyclic group, an aromatic group, an arylaliphatic group, and an arylalicyclic group, comprising 0 to about 3 heteroatoms selected from the group N, O, S, Se and Si, (f) reacting oxazolinidone (13) to form azido carboxylate ester (2) wherein R 18 and R 19 are independently selected from the group consisting of a silyl-group, an aliphatic, alicyclic, aromatic, arylaliphatic, and arylalicyclic group, comprising 0 to about 3 heteroatoms selected from the group N, O, S, Se and Si, and (g) converting azido carboxylate ester (2) to 4,5-diamino cyclohexene carboxylate ester (1).