A metal-free approach towards synthesis of β-carboline C1 substituted Pyrido(2,3-c)carbazole derivatives (nitramarine analogues) through A3-coupling and estimation of their light emitting properties

A Review on Molecular Iodine Catalyzed/Mediated Multicomponent Reactions

“…An iodine catalyzed multicomponent synthesis of fluorescent β‐carboline tethered pyrido[2,3‐ c ]carbazole derivatives (highly functionalized quinolines) 44 in good yields was reported by Singh et al [54] . via reaction of 3‐amino‐9‐ethylcarbazole, terminal alkynes and 1‐formyl‐9H‐β‐carbolines in acetonitrile (Scheme 23).…”

“…An iodine catalyzed multicomponent synthesis of fluorescent β-carboline tethered pyrido[2,3-c]carbazole derivatives (highly functionalized quinolines) 44 in good yields was reported by Singh et al [54] via reaction of 3-amino-9-ethylcarbazole, terminal alkynes and 1-formyl-9H-β-carbolines in acetonitrile (Scheme 23). 1-Formyl-9H-β-carbolines in acetonitrile react with amine component giving imine which upon A 3 -coupling with alkyne gives propargylic amine intermediate which results in the formation of dihydro[2,3c]carbazoles via 6-endo-dig cyclization which upon further dehydrogenation affords the desired product.…”

A cascade A3 coupling strategy towards the regioselective synthesis of β-carboline N-fused pyrrole derivatives with pyridine tethers

“…28 Similarly, our group also reported the synthesis of β-carboline substituted pyrido(2,3- c )carbazole derivatives by the application of an A 3 coupling reaction wherein 3-aminocarbazoles were explored as an amine component (eqn (4)). 29 Interestingly, a 3-component reaction of 1-formyl-9 H -β-carbolines with 2-aminopyridine and isonitriles (instead of alkyne) resulted in the formation of an imidazo[1,2- a ]pyridine framework showing that the nitrogen of 2-aminopyridine was more nucleophilic than the nitrogen of the β-carboline ring (N2) (eqn (5)). 30 Therefore, it was envisaged to execute a study in the presence of two nucleophilic pyridines (β-carboline ring vs. 2-aminopyridine) for an A 3 coupling as it could be challenging to control the regioselectivity owing to the possibility of formation of β-carboline N -fused pyrrole and/or an imidazo[1,2- a ]pyridine framework.…”

Potassium Tert‐Butoxide‐Promoted Synthesis of Fluorescent β‐Carboline Tethered 1,3,5‐Triazines and Assessment of Their Luminescent Properties

“…Therefore, the development of more efficient and facile approaches for the synthesis of novel 1,3,5‐triazines from simple precursors continues to be a challenging task. In a recent research endeavor, we achieved the synthesis of Nitramarine analogues via A 3 ‐coupling of Aldehyde (Kumujian C), Alkyne and Anilines [15] . In an extension to this study, we were interested to develop a variant of A 3 ‐coupling wherein it was envisaged to explore amidines as an amine component instead of conventional secondary or primary amines to generate the Annomontine analogues having a pyrimidine skeleton [16] …”

“…In a recent research endeavor, we achieved the synthesis of Nitramarine analogues via A 3 -coupling of Aldehyde (Kumujian C), Alkyne and Anilines. [15] In an extension to this study, we were interested to develop a variant of A 3 -coupling wherein it was envisaged to explore amidines as an amine component instead of conventional secondary or primary amines to generate the Annomontine analogues having a pyrimidine skeleton. [16] We initiated the study with the attempted synthesis of βcarboline substituted pyrimidine derivatives via A 3 -coupling of N-methyl Kumujian C, benzamidine hydrochloride and phenyl acetylene in presence of Cu/Zn catalysts; however, we obtained the dissimilar but quite interestingly results and ended with βcarboline linked triazine derivatives.…”