Compounds having the following formula:
are useful in treating disease conditions mediated by matrix metalloproteinases and TACE, such as tumor growth, osteoarthritis, rheumatoid arthritis and degenerative cartilage loss.
Compounds are provided having the following formula: ##STR1## wherein R, R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are defined in the specification, which have matrix metalloproteinase inhibiting activity.