Washington firm Patton Boggs’ is set to turn its back on a merger offer by Dentons as a rival deal from Squire Sanders is understood to be close to completion.

A source involved in the discussions told Legal Week that Dentons’ offer of a merger with Patton Boggs – described by the former firm’s chief executive Elliott Portnoy in April as a “serious overture” – had yielded no further developments or discussions.