The present application describes novel barbituric acid derivatives of
formula I: ##STR00001## or pharmaceutically acceptable salt or prodrug
forms thereof, wherein A, B, L, R.sup.1, R.sup.2, R.sup.3, R.sup.4,
R.sup.5, n, W, U, X, Y, Z, U.sup.a, X.sup.a, Y.sup.a, and Z.sup.a are
defined in the present specification, which are useful as TNF-.alpha.
converting enzyme (TACE) and matrix metalloproteinases (MMP) inhibitors.