(S)-N-Boc-(2-hydroxyethyl)piperazine-HCl

(S)-tert-butyl 2-(2-hydroxyethyl)piperazine-1-carboxylate

(S)-tert-butyl 2-(2-hydroxyethyl)piperazine-1-carboxylate-HCl

(S)-2-(2-Hydroxyethyl)piperazine-1-carboxylic acid tert-butyl ester