for the following products
(S)-2-((tert-Butoxycarbonyl)amino)-4,4-dimethylpentanoic acid | Boc-b-tBu-Ala-OH | Boc-beta-tBu-Ala-OH | Boc-β-tert-butyl-L-alanine | N-(tert-Butoxycarbonyl)-L-neopentylglycine | N-(tert-Butyloxycarbonyl)-N-tert-Butyl-beta-alanine and Boc-L-NptGly-OH