2β-(chloromethyl)penams has been successfully performed by treatment with aqueous sodiumnitrite in a two-layer solution comprising aqueous hydrochloric acid and dichloromethane layers. Similarly, the corresponding 2β-(bromomethyl)penams can be obtained by use of aqueous hydrobromicacid in place of aqueous hydrochloric acid.
A straightforward access to penicillanates bearing SCN and SeCN groups at the 2 β-methyl group was performed by electrolysis of 4-dithioazetidinones in a two-phase system (aqueous and organic phases) in the presence of KSCN and KSeCN, respectively, while a mixture of 2β-azidomethyl derivative and its 2α-isomer (6/4) was obtained by a similar electrolysis with NaN3.