~ 46 ~ International Journal of Chemical Studies 2015; 3(3): 46-52 P-ISSN2349–8528 E-ISSN 2321–4902 IJCS 2015; 3(3): 46-52 © 2015 JEZS Received: 13-08-2015 Accepted: 14-09-2015 Ofentse Mazimba Botswana Institute for Technology Research and Innovation, Private Bag 0082, Gaborone, Botswana. Tracy CS Molefe University of Botswana, Private Bag 0022, Gaborone, Botswana. Correspondence: Ofentse Mazimba Botswana Institute for Technology Research and Innovation, Private Bag 0082, Gaborone, Botswana. 1, 5-Benzodiazepines: A Review Update Ofentse Mazimba, Tracy CS Molefe Abstract 1,5-benzodiazepines are the most studied group of diazepines, which are a class of drugs prescribed against psychotic disorders. An immense literature is continually produced from the research work carried out about the synthesis and pharmacological activities of 1,5-benzodiazepine, two recent reviews in 2013 outlined the importance of this privileged pharmacophore. Due to their wide range of biological properties the benzodiazepine nucleus has continued to attract many investigators to synthesize and screen their analogues for all possible activities. This current review article describes the literature relating to 1,5-benzodiazepines synthetic strategies and provides highlights of the different pharmacological activities accomplished since 2013. Keywords: 1,5-Benzodiazepines, Anxiolytic, Synthesis, o-Phenylenediamine, Ketones, Catalyst, Solvent-free 1. Introduction Benzodiazepines are an important pharmacophore due to their pharmacotherapeutic properties and various pharmacopeial information. The 1,5-benzodiazepine nucleus is a privileged scaffold that is a core structure of medicinal drugs and has received great attention of medicinal research searching for new derivatives with enhanced pharmacological activities [1, 2, 3] . The bicyclic, tricyclic, tetracyclic and fused polycyclic 1,5-benzodiazepines exist in literature [4] . The benzodiazepines have revolutionized the treatment of anxiety and insomnia since the 1950s with the introduction of chlordiazepoxide [5] largely due to their anxiolytic and sedative-hypnotic effects [6] . The 1,5-benzodiazepine have retained attention due to their pharmacological activities and immense literature exist on the benzodiazepine nucleus. Bariwal and co-workers [7] . Reviewed the pharmacological profiles of structurally enhanced 1,5-benzodiazepines. Salvi and Mali [3] review article reported on the various synthetic routes, solvents and catalysts used towards 1,5- benzodiazepines and their different pharmacological activities, while another recent review by Aastha and co-workers [1] . Provided an overview of the biological properties and synthetic schemes for 1,5-benzodiazepine. Casher and co-workers [8] . have described benzodiazepines as versatile clinical tools and a review showing the compendium on genotoxicity and carcinogenicity data for benzodiazepines drugs appeared in 2007 [9] . Post the 2013 [1] reviews a significant number of articles have appeared in literature reporting on the synthesis and screening of 1,5-benzodiazepine analogues for all possible activities. Therefore, this review describes the synthesis of 1,5-benzodiazepine analogues and highlights the different pharmacological activities from the last two years (2013-2015). 2. Discussion 2.1 The ring system The IUPAC ring numbering of the simplest form of 1,5-benzodiazepine (2, 3-dihydro-1H-1, 5 benzodiazepine) is shown in Figure 1. The structure has two nitrogen atoms at positions 1 and 5 in a seven membered diazepine ring fused to a benzene ring. The ring system occurs in the diimine forms where there is conjugation between the two imino groups and the benzene ring, which bring stability to the system [10-13] . 1 3 5 7 5a 9 N N Figure 1