for the following products
(S)-2-N-Boc-Amino-3-hydroxy-3-methylbutyric acid | Boc-beta,beta-diMe-L-Ser-OH | N-alpha-tert-Butyloxycarbonyl-beta,beta-dimethyl-L-serine | N-Boc-(S)-2-Amino-3-hydroxy-3-methylbutanoic acid and (2S)-2-(N-tert-Butoxycarbonyl)amino-3-hydroxy-3-methylbutanoic acid