Mannose

(3S,4S)-3-[(R)-1-(tert-butyldimethylsilyloxy)ethyl]-4-[(RS)-1-(hydroxycarbonyl)ethyl]-2-azetidinone

Butyldimethylsilyloxyethylcarboxyet

1-BMA

(3S,4S)-4-[(R)-1-carboxy-ethyl]-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone

β-methylazetidin-2-one

[2R-[2α(R*),3β(R*)] ]-3-[1-[[(1,1-dimethylethyl)dimethylsilyl]oxy]ethyl]-α-methl-4-oxo-2-azetidineacetic acid

(R)-2-((2S,3S)-3-((R)-1-(TERT-BUTYLDIMETHYLSILYLOXY)ETHYL)-4-OXOAZETIDIN-2-YL)PROPANOIC ACID

side chain for imipenem

4-BMA

(3S,4S)-4-[(R)-1-carboxyethyl]-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-2-azetidinone

(3S 4S)-3-[(R)-1-(T-BUTYLDIMETHYLSILYLOXY)ETHYL]-4-[(R)-1-CARBOXYETHYL]-2-AZETIDINONE

(3S,4S)-3-[(R)-1-(TERT-BUTYLDIMETHYLSILOXY)ETHYL]-4-[(R)-1-CARBOXYETHYL]-2-AZETIDINONE

(3S,4S)-3-[(R)-1-(TERT-BUTYLDIMETHYLSILYLOXY)ETHYL]-4-[(R)-1-CARBOXYETHYL]-2-AZETIDINONE

(3S,4S)-3-[(R)-(BUTYLDIMETHYLSILYLOXY)ETHYL]-4-[(R)-CARBOXYETHYL]-2-AZETIDINONE

4-BMA(for Meropenem)

4BMA

(2R)-2-{(2S,3S)-3-[(1R)-1-{[tert-butyl(dimethyl)silyl