Compounds of Formula (I), wherein represents a single bond when G is —OH and double bond when G is —O; R1 and R2 are independently selected from hydrogen, alkyl, alkenyl, alkynyl, aralkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, heterocyclylalkyl or heteroarylalkyl; R3 is selected from the group selected from hydrogen, hydroxy, alkoxy, alkenyloxy or alkynyloxy; X is selected from oxygen, —NH, —NR (wherein R is alkyl, alkenyl, alkenyl, alkynyl or aryl), sulphur or no atom; Het is heterocyclyl or heteroaryl; n is an integer from 1 to 6; are muscarinic receptor antagonists, which are useful, among other uses, for the treatment of various diseases of the respiratory, urinary and 4 i gastrointestinal systems mediated through muscarinic receptors.