Abstract. In this paper, we develop a syntactical version of elaborated reductions for high-level Petri nets. These reductions simplify the model by merging some sequential transitions into an atomic one. Their conditions combine local structural ones (e.g. related to the actions of a thread) and global algebraic ones (e.g. related to the threads synchronization). We show that these conditions are performed in a syntactical way, when a syntax of the color mappings is given. We show also how our method outperforms previous ones on a recent case study with regard both to the reduction ratio and the automatization of their application.