p. 3235 - 3238
(2007/10/03)(2S,3R)-3-(1-tert-Butoxycarbonyl-azetidin-3-ylmethyl)-1-(tert-butyl-dimethyl-silanyl)-4-oxo-azetidine-2-carboxylic acid
(2S,3R)-3-(1-tert-Butoxycarbonyl-azetidin-3-ylmethyl)-4-oxo-azetidine-2-carboxylic acid
(2S,3R)-3-(1-tert-Butoxycarbonyl-azetidin-3-ylmethyl)-4-oxo-azetidine-2-carboxylic acid benzyl ester