Heterocyclic Bridgehead Nitrogen Atom System: Review on [1,2,4] Triazolo[3,4-b] [1,3,4] thiadiazole and Its Pharmacological Screening.

There has been considerable interest in the development of novel anticonvulsant compounds, , analgesic, anti-inflammatory, antimicrobial, antimycobacterial, antitumour, and antitubercular activities. 1,3,4-thiadiazole constitute Significant class of compounds for new drugs development. They Have an interesting pharmacophore displaying a wide range of pharmacological activity. The 1,3,4-thiadiazole compound is an interesting heterocycle. A group that was used to synthesise a variety of useful bioactive compounds. The stability of the thiadiazole nucleus has inspired the medicinal chemist to perform various structural variations in the ring. Marketed drugs such as acetazolamide and methazolamide have shown their therapeutic potential Therefore, many researchers have identified these compounds as target structures and evaluated their biological activities. This review highlights the different pharmacological activities associated with the 1,3,4-thiadiazole ring system.

Condensed Pyridopyrimidines and Pyridopyrazines Containing a Bridgehead Nitrogen Atom: Synthesis, Chemical Properties and Biological Activity

: The investigation of effective and green synthetic routes to approach to novel fused heterocycles with pyridopyrimidine and pyridopyrazine scaffolds stirs up broad interest from scientists as they are capable of providing valuable properties such as anticancer and antimicrobial activities and they are proved γ-secretase modulators, polymers, and corrosion inhibitors. This causes a steady increase in the number of publications on titled condensed systems. The present review article summarizes recent literature data from 2010 to 2020 on the methods of synthesis, chemical transformations and biological properties of condensed bicyclic systems of pyridopyrimidine and pyridopyrazine with a bridgehead nitrogen atom to establish the current state of the art in this area.

Synthesis of new quinolizinium-based fluorescent compounds and application studies on photocatalysis

Quinoliziniums, cationic aromatic heterocycles bearing a quaternary bridgehead nitrogen, have been widely applied to research areas, such as fluorescent dyes, DNA intercalators and ionic liquids. A library of new quinolizinium...

A four-component domino reaction for the synthesis of novel bridgehead nitrogen-containing pyrido[1,2-d][1,4]diazepines

An efficient one-pot four-component reaction for the synthesis of a new family of novel bridgehead nitrogen-containing pyrido[1,2-d][1,4]diazepines has been described and its mechanism has been proposed, which follows a ring-closure...

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

The Castagnoli–Cushman reaction of 3,4-dihydroisoquinolines with glutaric anhydride, its oxygen and sulfur analogues was investigated as a one-step approach to the benzo[a]quinolizidine system and its heterocyclic analogs. An extension towards the pyrrolo[2,1-a]isoquinoline system was achieved with the use of succinic anhydride. The results are evidence of an unexplored method for the access of the aforementioned tricyclic annelated systems incorporating a bridgehead nitrogen atom. The structures and relative configurations of the new compounds were established by means of 1D and 2D NMR techniques. The reactions between 1-methyldihydroisoquinoline and glutaric, diglycolic and succinic anhydrides yielded unexpected isoquinoline derivatives containing an exocyclic double bond. The compounds prepared bear the potential to become building blocks for future synthetic bioactive molecules.

Hantzsch-Like Three-Component Synthesis of 9,10-Dihydro-3H-10a-azaphenanthrene-2,4-dicarbonitriles

A novel series of 9,10-dihydro-3H-10a-azaphenanthrene-2,4-dicarbonitrile derivatives that contain a bridgehead nitrogen were prepared by a three-component reaction of aldehydes, 2-(6,7-dimethoxy-3,4-dihydroisoquinolin-1-yl)acetonitrile, and 3-aminocrotononitrile in acetic acid.