has 0 to 1 double bonds and each 6 membered ring has 0 to 2 double bonds iii the nitrogen and sulfur heteroatoms may optionally be oxidized iv the nitrogen heteroatom may optionally be quaternized and iv any of the above rings may be fused to a benzene ring representative heterocycloalkyl groups include but are not limited to 1 3 dioxolane pyrrolidinyl pyrazolinyl pyrazolidinyl imidazolinyl imidazolidinyl piperidinyl piperazinyl oxazolidinyl isoxazolidinyl morpholinyl thiazolidinyl isothiazolidinyl and tetrahydrofuryl the term u201c substituted heterocycloalkyl u201d as used herein refers to a heterocycloalkyl group as previously defined substituted by independent replacement or one two or three of the hydrogen atoms thereon with f cl br i oh no 2 cn c 1 c 6 alkyl oh c o u2014 c 1 c 6 alkyl och 2 u2014 c 3 c 12 cycloalkyl c o aryl c o heteroaryl co 2 alkyl co 2 aryl co 2 heteroaryl conh 2 conh u2014 c 1 c 6 alkyl conh aryl conh heteroaryl oc o u2014 c 1 c 6 alkyl oc o aryl oc o heteroaryl oco 2 alkyl oco 2 aryl oco 2 heteroaryl oconh 2 oconh u2014 c 1 c 6 alkyl oconh aryl oconh heteroaryl nhc o u2014 c 1 c 6 alkyl nhc o aryl nhc o heteroaryl nhco 2 alkyl nhco 2 aryl nhco 2 heteroaryl nhconh 2 nhconh u2014 c 1 c 6 alkyl nhconh aryl nhconh heteroaryl so 2 u2014 c 1 c 6 alkyl so 2 aryl so 2 heteroaryl so 2 nh 2 so 2 nh u2014 c 1 c 6 alkyl so 2 nh aryl so 2 nh heteroaryl c 1 c 6 alkyl c.