A process for purification of protected tricyclic carbamoylpyridone derivatives of Formula II, or a stereoisomer thereof; wherein P is hydroxy protecting group selected from straight or branched chain C 1-8 alkyl group, C 1-8 halo alkyl, substituted or unsubstituted silyl or C 6-14 aryl; Ar is aryl substituted with one to three halogens; V 1 and V 2 are each independently, hydrogen, C 1-6 alkyl, or C 1-6 haloalkyl; or V 1 and V 2 together with the carbon atom to which they are attached, form a carbocyclic ring having from 3 to 6 ring atoms or a heterocyclic ring having from 3 to 6 ring atoms, wherein the carbocyclic or a heterocyclic ring is optionally substituted with one or more R a group; X is -O-; Y is -CHV 5 ; Z is a bond, (-CH 2 -) n or Y and Z taken together form (-CH 2 -) n ; wherein n is an integer of 0 to 3; V 3 and V 5 are each independently, hydrogen or C 1-6 alkyl, C 6-14 aryl; or wherein V 3 and V 5 taken together form a carbocyclic ring containing having from 3 to 6 ring atoms or a heterocyclic ring having from 3 to 6 ring atoms, wherein the carbocyclic or heterocyclic ring is optionally substituted with one or more R a group, wherein each R a is, independently, hydrogen, halo, hydroxyl or C 1-6 alkyl, or wherein two R a groups together with the carbon atom to which they are attached to form =O; which comprises; a) reacting a compound of Formula II comprising a compound of Formula III, wherein P, Ar, V 1 , V 2 , V 3 , X, Y and Z are as defined above; with a C 2 -C 20 substituted or unsubstituted cyclic anhydride in a suitable organic solvent; b) treating the reaction mass with an aqueous basic solution and separating the organic layer and aqueous layer; and c) isolating the compound of Formula II substantially free of compound of Formula III from the organic layer. or a stereoisomer thereof; wherein P is hydroxy protecting group selected from straight or branched chain C 1-8 alkyl group, C 1-8 halo alkyl, substituted or unsubstituted silyl or C 6-14 aryl; Ar is aryl substituted with one to three halogens; V 1 and V 2 are each independently, hydrogen, C 1-6 alkyl, or C 1-6 haloalkyl; or V 1 and V 2 together with the carbon atom to which they are attached, form a carbocyclic ring having from 3 to 6 ring atoms or a heterocyclic ring having from 3 to 6 ring atoms, wherein the carbocyclic or a heterocyclic ring is optionally substituted with one or more R a group; X is -O-; Y is -CHV 5 ; Z is a bond, (-CH 2 -) n or Y and Z taken together form (-CH 2 -) n ; wherein n is an integer of 0 to 3; V 3 and V 5 are each independently, hydrogen or C 1-6 alkyl, C 6-14 aryl; or wherein V 3 and V 5 taken together form a carbocyclic ring containing having from 3 to 6 ring atoms or a heterocyclic ring having from 3 to 6 ring atoms, wherein the carbocyclic or heterocyclic ring is optionally substituted with one or more R a group, wherein each R a is, independently, hydrogen, halo, hydroxyl or C 1-6 alkyl, or wherein two R a groups together with the carbon atom to which they are attached to form =O; which comprises; a) reacting a compound of Formula II comprising a compound of Formula III, wherein P, Ar, V 1 , V 2 , V 3 , X, Y and Z are as defined above; with a C 2 -C 20 substituted or unsubstituted cyclic anhydride in a suitable organic solvent; b) treating the reaction mass with an aqueous basic solution and separating the organic layer and aqueous layer; and c) isolating the compound of Formula II substantially free of compound of Formula III from the organic layer. a) reacting a compound of Formula II comprising a compound of Formula III, wherein P, Ar, V 1 , V 2 , V 3 , X, Y and Z are as defined above; with a C 2 -C 20 substituted or unsubstituted cyclic anhydride in a suitable organic solvent; b) treating the reaction mass with an aqueous basic solution and separating the organic layer and aqueous layer; and c) isolating the compound of Formula II substantially free of compound of Formula III from the organic layer. <EOS>