Hydrochloric Acid → HCID 67074996, compound

Participants

Reaction Steps

In analogy to the procedure described in example 120 step D, (2S,5RS)-4-(3-tert-butoxycarbonyl-propyl)-5-carbamoyl-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester was first hydrolysed with HCl and then coupled with (S)-6-aza-spiro[2.5]octan-4-ol hydrochloride (intermediate 2). The two diasterioisomers could be separated by flash column chromatography (SiO2, EtOAc/MeOH 1:0-9:1) affording first (2S,5R)-5-carbamoyl-4-[4-((S)-4-hydroxy-6-aza-spiro[2.5]oct-6-yl)-4-oxo-butyl]-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester in 22% yield as an amorphous white solid, MS: 487.30 (MH+) and then (2S,5S)-5-carbamoyl-4-[4-((S)-4-hydroxy-6-aza-spiro[2.5]oct-6-yl)-4-oxo-butyl]-2-methyl-3-oxo-piperazine-1-carboxylic acid benzyl ester in 20% yield as a colorless foam MS: 487.30 (MH+).

Provenance & Evidence