Current Organic Chemistry - Volume 23, Issue 10, 2019

Nitrogen-containing heterocycles (NCH), constitute an important group of molecules, which are widely extended in whole chemical space. These compounds are of great interest due to their diverse biological activities. Currently, many compounds derived from NCH are used as powerful drugs for the treatment of diseases ranging from bactericides to anticancer agents. During last decade, the enantioselective synthesis of numerous heterocyclic compounds has been achieved through the use of chiral organocatalysts. The present contribution explores the application of the aminocatalysis towards the synthesis of NCH, particularly through the trienamine catalysis.

This review article is focused on the synthesis of compounds with quinazolinones and benzo di/triazepine scaffolds. These invaluable derivatives are of great interest in medicinal and pharmaceutical studies because of their important biological properties. Quinazolinones have diverse applications due to their antibacterial, analgesic, antiinflammatory, antifungal, antimalarial, antihypertensive, CNS depressant, anticonvulsant, antihistaminic, antiparkinsonism, antiviraland and anticancer activities. On the other hand, pharmacological properties of benzodiazepines include antianxiety, anticancer, anticonvulsant, antagonists of cholecystokinin receptors (CCK), antileishmanial, sleep-inducing muscle relaxant and several other useful and interesting properties. As an example, three main categories of drugs, namely anxiolytics, sedative hypnotics (sleep inducers) and anticonvulsants are constructed by 1,4-benzodiazepines. Finally, benzotriazepines are believed to possess various pharmacological properties such as antipsychotic and antitumor activities. Hence, this review is divided into three major sections, considering quinazolinones, benzodiazepines and benzotriazepines. In the first section, we take a brief look at various approaches towards synthesis of substituted quinazolin-4(3H)-ones and 2,3-dihydroquinazolin-4(1H)-ones. Also in this section, we try to give an overview of the synthetic routes and strategies recently reported for the generation of various classes of substituted 4(3H)-quinazolinones and 2,3-dihydroquinazolin-4(1H)-ones. Accordingly, quinazolin-4(3H)-ones, were subdivided into three major classes: 2-substituted, 3-substituted and 2,3-disubstituted-quinazolinones. 2,3- dihydroquinazolin-4(1H)-ones also were subdivided into six sub-categories: 2-monosubstituted, 2,2- disubstituted, 2,3-disubstituted, 1,2,3-trisubstituted, 2,2,3-trisubstituted 2,3-dihydroquinazolin-4(1H)-ones and boron-containing quinazoline-4(1H)-ones. In the other two sections, we cover the literature related to synthesis of benzo di/triazepine. The most recent developments are highlighted with a special emphasis on new synthetic routes based on isatoic anhydride as starting material.

Nitro hydrocarbons as inexpensive, easily available, and relatively stable organic intermediates have aroused great attention in various functional group transformations over the past several decades. The electron-withdrawing action of the nitro group can act as a transient leaving group to efficiently transform into the other important functionalities. Nitro compounds are easily prepared through simple synthetic reactions from simple and facile starting substrates and provide an exciting opportunity for the synthesis of various valuable products. This account will review recent progress in the denitrative coupling reaction of nitroalkanes, nitroolefins, and nitroarenes under transition metalcatalyzed, transition metal-free, or visible light induced conditions.

Bromopyridines, bromotiophenes and 3-bromofuran were reacted with diphenylphosphine oxide or diethyl phosphite under microwave irradiation using Pd(OAc)2 as the catalyst precursor together with some excess of the >P(O)H reagent. Hence, there was no need for the usual mono- and bidentate P-ligands. The >P(O)-functionalized heterocycles were obtained in variable (55-95%) yields. The results of our “green” protocol were in most cases better than those of the literature methods.

Triepoxides were synthesized for the first time in high yields (80-85%) by oxidation of substituted bicyclo[4.2.2]deca-2,4,7,9-tetraenes, bicyclo[4.2.2]deca-2,4,7-trienes, and tricyclo[9.4.2.02,10]heptadeca-2,12,14,16-tetraene with an excess of m-chloroperbenzoic acid. The structures of the epoxy derivatives were reliably proved using modern spectral methods and X-ray diffraction analysis. A high antitumor activity in vitro was found for triepoxides against the Jurkat, K562, U937 tumor cell lines and normal fibroblasts.