1 XD1 (2r,4s)-2-[(1r)-1-amino-2-oxoethyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid 1.000 2 ALP 2-(1-carboxy-2-hydroxy-ethyl)-5,5-dimethyl-thiazolidine-4-carboxylic acid 0.765 3 2V0 (2r)-2-[(R)-amino(carboxy)methyl]-5-methyl-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.706