75562-84-4Relevant academic research and scientific papers
Hydrolytic behavior of two β-lactams and their corresponding imidate salts. New evidence for stereoelectronic control
Deslongchamps, Pierre,Caron, Maurice
, p. 2061 - 2068 (2007/10/02)
The basic hydrolysis and the concurrent carbonyl-oxygen exchange of 18O-labelled N-phenyl-4-phenyl-2-azetidinone (5*) and N-2,6-dimethylphenyl-2-azetidinone (6*) have been studied. β-Lactam 5* was easily hydrolysed and showed no carbonyl-oxygen exchange with 0.1 N sodium hydroxide (dioxane - water, 9:1).Under the same conditions, β-lactam 6* gave no exchange and was found resistant to basic hydrolysis.Hydrolysis and exchange was observed when 6* was refluxed with 0.1 N and 1 N sodium hydroxide in water.The hydrolysis of the corresponding imidate salts 7 and 8 was also investigated.Under basic conditions, salt 7 gave and 8:2 mixture of ester amine 9 and β-lactam 5, while under acidic conditions the hydrochloride salt of ester amine 9 was the only product.Under basic conditions, the imidate salt 8 produced only the β-lactam 6, and under acidic conditions, a 3:7 mixture of the hydrochloride salt of 10 and β-lactam 6.Under stronger acidic conditions (>/=3 N HCl), 8 gave only the starting β-lactam 6.The results of these hydrolysis reactions are easily explained on the basis of the stereoelectronic theory for the cleavage of tetrahedral intermediates, and by taking into account that the nitrogen of tetrahedral intermediates must be either protonated under acidic conditions, or hydrogen bonded with the solvent under basic conditions in order to observe the cleavage of the C-N bond.
