A compound of the formula: wherein, R 1 is substituted or unsubstituted C 1 -C 6 alkyl, (wherein R a is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, or substituted or unsubstituted C 3 -C 8 cycloalkyl); R 2 is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl; R 3 and R 4 are independently selected from substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted amine, substituted or unsubstituted C 3 -C 8 cycloalkyl, substituted or unsubstituted heterocyclyl, or substituted or unsubstituted heteroaryl, or R 3 and R 4 are taken together with the carbon atom to which they are attached to form substituted or unsubstituted C 3 -C 8 cycloalkyl, epoxide, oxetane or azetidine; R 5 and R 6 are independently selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl or R 5 and R 6 are taken together with the carbon atom to which they are attached form substituted or unsubstituted C 3 -C 8 cycloalkyl or R 5 and R 6 together represent oxo; R 7 is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted amino, substituted or unsubstituted C 1 -C 6 amino alkyl, substituted or unsubstituted C 3 -C 8 cycloalkyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted heteroaryl, or -S 2 R b; wherein the substituents are independently selected from one or more R m; R m is selected from halo, C 1 -C 6 alkyl, haloalkyl, amino, -C OR c, substituted or unsubstituted heterocyclyl, substituted or unsubstituted heterocyclylalkyl, substituted or unsubstituted heteroaryl or -S 2 R b; R b and R c are independently selected from substituted or unsubstituted C 1 -C 6 alkyl or substituted or unsubstituted C 6 -C 12 aryl; 'n' is an integer selected from 0, 1 or 2; pharmaceutically acceptable salts, pharmaceutically acceptable solvates, pharmaceutically acceptable hydrates, tautomers, or combination thereof. R 1 is substituted or unsubstituted C 1 -C 6 alkyl, (wherein R a is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, or substituted or unsubstituted C 3 -C 8 cycloalkyl); R 2 is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl; R 3 and R 4 are independently selected from substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted amine, substituted or unsubstituted C 3 -C 8 cycloalkyl, substituted or unsubstituted heterocyclyl, or substituted or unsubstituted heteroaryl, or R 3 and R 4 are taken together with the carbon atom to which they are attached to form substituted or unsubstituted C 3 -C 8 cycloalkyl, epoxide, oxetane or azetidine; R 5 and R 6 are independently selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl or R 5 and R 6 are taken together with the carbon atom to which they are attached form substituted or unsubstituted C 3 -C 8 cycloalkyl or R 5 and R 6 together represent oxo; R 7 is selected from hydrogen, substituted or unsubstituted C 1 -C 6 alkyl, substituted or unsubstituted C 1 -C 6 alkoxy, substituted or unsubstituted amino, substituted or unsubstituted C 1 -C 6 amino alkyl, substituted or unsubstituted C 3 -C 8 cycloalkyl, substituted or unsubstituted C 6 -C 12 aryl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted heteroaryl, or -S 2 R b; wherein the substituents are independently selected from one or more R m; R m is selected from halo, C 1 -C 6 alkyl, haloalkyl, amino, -C OR c, substituted or unsubstituted heterocyclyl, substituted or unsubstituted heterocyclylalkyl, substituted or unsubstituted heteroaryl or -S 2 R b; R b and R c are independently selected from substituted or unsubstituted C 1 -C 6 alkyl or substituted or unsubstituted C 6 -C 12 aryl; 'n' is an integer selected from 0, 1 or 2; pharmaceutically acceptable salts, pharmaceutically acceptable solvates, pharmaceutically acceptable hydrates, tautomers, or combination thereof.