FUSED HETEROCYCLYL DERIVATIVES AS NAMPT INHIBITORS
Provided are substituted heterocyclyl derivatives of formula (I), which may be the therapeutically useful, more particularly as NAMPT inhibitors; in which R 1, R 2, X 1, X 2, ring A, L and 'n' have the meanings given in the specification, and pharmaceutically acceptable salts thereof that are useful in the treatment and prevention of diseases or disorder caused by an elevated level of nicotinamide phosphoribosyltransferase (NAMPT) in a mammal. Also provided are preparation of the compounds and pharmaceutical formulations comprising at least one of the substituted fused heterocyclyl derivatives of formula (I) or pharmaceutically acceptable salts or stereoisomers thereof.