<3S-<3α(S*),4α>>ethyl 1-(2,4-dimethoxybenzyl)-3-(1-acetoxyethyl)-2-azetidinone-4-carboxylate

<3S-<3α(S*),4β>>ethyl 1-(2,4-dimethoxybenzyl)-3-(1-acetoxyethyl)-2-azetidinone-4-carboxylate

<1R-(1α,4α,5α)>-7-(2,4-dimethoxybenzyl)-2,6-dioxo-4-methyl-3-oxa-7-azabicyclo<3.2.0>heptane