1 HJ2 (2r)-2-[(R)-{[(6s)-6-amino-6-carboxyhexanoyl]amino}(carboxy)methyl]-5-methyl-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 1.000 2 REC Cephalosporin 1.000 3 HJ3 (2r,4s)-2-[(1r)-1-{[(6s)-6-amino-6-carboxyhexanoyl]amino}-2-oxoethyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid 0.821