| abstract |
Compounds of formula I:wherein R<1>, R<2>, R<3>, R<4 >and n have any of the values defined in the specification, and their pharmaceutically acceptable salts, are useful for inhibiting beta-lactamase enzymes, for enhancing the activity of beta-lactam antibiotics, and for treating beta-lactam resistant bacterial infections in a mammal. The invention also provides pharmaceutical compositions, processes for preparing compounds of formula I, and novel intermediates useful for the synthesis of compounds of formula I. |