Model driven architecture (MDA) is a software development framework based on automatic transformations of models. The first of these models, the computation independent model (CIM), is used to define the business system, and it is usually represented with UML models. Natural language is widely used in requirements engineering as it is generally understandable by stakeholders encouraging their participation. Therefore, in order to enhance the first stages of MDA software development, we propose to define natural language oriented requirements models and derive from them a CIM. To achieve this integration we describe in this paper an automatic process to derive a business class diagram representing the structural aspects of a CIM starting from natural language oriented models.