p. 246 - 247
(2002)p. 979 - 982
(1997)(2021/11/06)
p. 2533 - 2536
(2007/10/03)(2S)-1,4-bis(tert-butoxycarbonyl)piperazine-2-carboxylic acid
(S)-4-(tert-butoxycarbonyl)piperazine-2-carboxylic acid
(S)-4-(benzyloxycarbonyl)piperazine-2-carboxylic acid
(S)-4-benzyl 1-tert-butyl 2-(hydroxymethyl)piperazine-1,4-dicarboxylate
(S)-4-benzyl 1-tert-butyl 2-methyl piperazine-1,2,4-tricarboxylate