194 RECENT ADVANCES IN THE SYNTHESIS OF NEW PYRAZOLE DERIVATIVES DOI: http://dx.medra.org/ 10.17374/targets.2019.22.194 Juan - Carlos Castillo a,b , Jaime Portilla a * a Bioorganic Compounds Research Group, Department of Chemistry, Universi dad de los Andes, Carrera 1 No. 18A - 10, Bogotá, Colombia b Grupo de Cat álisis, E scuela de Ciencias Químicas, Universidad Pedagógica y Tecnológica de Colombia UPTC, Av enida Central del Norte, Tunja, Colombia (e - mail :
[email protected] ) Abstract. Pyrazoles have attracted great attention in organic and medicinal chemistry, due to their proven utility as synthetic intermediates for the preparation of diverse bioactive compounds, of coordination complexes, as well as in the design of functional materials. Consequently , the synthesis of functionalized pyrazoles is an important focus of research for synthetic organic chemists. Likewise, fuse d pyrazoles such as pyrazolo[1,5 - a]pyrimidines and pyrazolo[3,4 - b]pyridines have been widely studied due to their varied biological and physicochemical applications based on the important electronic properties of th ese N - heterocycles. Therefore, the preparation of these fused heterocycles and of their functionalized derivatives is of notable interest to both uncover novel derivatives and explore new applications. Several methods have been described in the literature for the synthesis of pyrazoles and of their fused systems in recent years , which mainly involve classi cal cyclocondensation reactions , some of these are presented in th is contribution. Contents 1. Introduction 2. Functionalized pyrazoles 2.1. Aminopyrazoles 2.2. Formylpyrazoles 3. Fused pyrazoles 3.1. Pyrazolo[1,5 - a ]pyrimidines 3.2. Pyrazolo[3,4 - b ]pyridines 3.3.