Heteroaryl derivatives of monocyclic beta-lactam antibiotics

DETAILED DESCRIPTION OF THE INVENTION Listed below are definitions of various terms used to describe the .
beta.
-lactams of this invention.
These definitions apply to the terms as they are used throughout the specification (unless they are otherwise limited in specific instances) either individually or as part of a larger group.
The terms "alkyl" and "alkoxy" refer to both straight and branched chain groups.
Those groups having 1 to 10 carbon atoms are preferred.
The term "cycloalkyl" refers to cycloalkyl groups having 3, 4, 5, 6 or 7 carbon atoms.
The term "substituted alkyl" refers to alkyl groups substituted with one or more (preferably 1, 2 or 3) azido, amino (--NH.
sub.
2), halogen, hydroxy, carboxy, cyano, alkoxycarbonyl, aminocarbonyl, alkanoyloxy, alkoxy, phenyloxy, (substituted phenyl)oxy, R.
sub.
a -oxy, mercapto, alkylthio, phenylthio, (substituted phenyl) thio, alkylsulfinyl, or alkylsulfonyl groups.
The terms "alkanoyl", "alkenyl", and "alkynyl" refer to both straight and branched chain groups.
Those groups having 2 to 10 carbon atoms are preferred.
The term "substituted alkanoyl" refers to alkanoyl groups substituted with one or more (preferably 1, 2 or 3) azido, amino (--NH.
sub.
2), halogen, hydroxy, carboxy, cyano, alkoxycarbonyl, aminocarbonyl, alkanoyloxy, alkoxy, phenyloxy, (substituted phenyl)oxy, mercapto, alkylthio, phenylthio, (substituted phenyl)thio, alkylsulfinyl or alkylsulfonyl groups.
The term "substituted phenyl" refers to a phenyl group substituted with 1, 2 or 3 amino (--NH2), halogen, hydroxyl, trifluoromethyl, alkyl (of 1 to 4 carbon atoms), alkoxy (of 1 to 4 carbon atoms), alkanoyloxy, aminocarbonyl, or carboxy groups.
The expression "a 4, 5, 6 or 7-membered heterocycle" (referred to as "R.
sub.
a ") refers to substituted and unsubstituted, aromatic and nonaromatic groups containing one or more (preferably 1, 2 or 3) nitrogen, oxygen or sulfur atoms.
Exemplary substituents are oxo (.
dbd.
O), halogen, hydroxy, nitro, amino, cyano, trifluoromethyl, alkyl of 1 to 4 carbons, alkoxy of 1 to 4 carbons, alkylsulfonyl, phenyl, substituted phenyl, 2-furfurylideneamino ##STR6## benzylideneamino and substituted alkyl groups (wherein the alkyl group has 1 to 4 carbons)