(3R,5R)-5-(tert-Butyl-dimethyl-silanyloxy)-tetrahydro-pyridazine-1,3-dicarboxylic acid 3-methyl ester 1-(2-trimethylsilanyl-ethyl) ester

(3R,5R)-5-(tert-Butyl-dimethyl-silanyloxy)-tetrahydro-pyridazine-1,3-dicarboxylic acid 1-(2-trimethylsilanyl-ethyl) ester

(3R,5R)-3-{(S)-1-[(1R,2S)-1-Allyloxycarbonyl-2-(tert-butyl-dimethyl-silanyloxy)-propylcarbamoyl]-3-methyl-butylcarbamoyl}-5-(tert-butyl-dimethyl-silanyloxy)-tetrahydro-pyridazine-1-carboxylic acid 2-trimethylsilanyl-ethyl ester

3-{1-[1-allyloxycarbonyl-2-(tert-butyl-dimethyl-silanyloxy)-propylcarbamoyl]-3-methyl-butylcarbamoyl}-5-(tert-butyl-dimethyl-silanyloxy)-2-(2-hydroxy-3-methyl-butyryl)-tetrahydro-pyridazine-1-carboxylic acid 2-trimethylsilanyl-ethyl ester