ITMS 8.x
The "Replicate Now" right-click option can be found under 'System Privileges' section (under Settings>Security>Account Management>'Select desired Role'>Privileges tab) and not visible under the Settings>Security>Permissions>Settings view>Hierarchy tree as it used to be (prior to ITMS 8.5 release).
'Replicate Now' is a privilege that can be assigned to a Security Role. If privilege 'ReplicateNow' is enabled then user can use it, if not then 'ReplicateNow' is invisible.