An appropriate approach for translating UML to B formal specifications allows one to use UML and B jointly in an unified, practical and rigorous software development. We formally analyze UML specifications via their corresponding B formal specifications. This point is significant because B support tools like \atelierb{} are available. We can also use UML specifications as a tool for building B specifications, so the development of B specifications become easier. This paper reports our recent results on formalizing UML behavioral diagrams in B notations. We are planning to present automatic derivation schemes from UML behavioral diagrams to B specifications. Our proposal together with the formalization in B of UML structure specifications provide a complete frameworks to translate UML specifications into B. We discuss also the perspectives for analyzing UML behavioral specifications via the derived B specifications.