Design and synthesis of benzothiazole/thiophene-4H-chromene hybrids

Abstract

A library of 4H-chromene derivatives with heterocyclic substituents at 3 and 4-positions was synthesized in a convenient DBU catalysed three component reaction.

Arylformylacetonitriles in Multicomponent Reactions Leading to Heterocycles

“…Earlier in 2018, the same group reported the formation of 2,3,4-trisubstituted chromenes 125 from the reaction of arylformylacetonitriles 1 with heterocyclic carbon nucleophiles 123 and salicylaldehydes 124 (Scheme 21, a). [158] The best yields were achieved using DBU as the catalyst, a mixture of ethanol and water (1 : 1) as the solvent, and after 2 h of reaction time at room temperature. In the same context, the MCRs of arylformylacetonitriles 1, with aldehydes 126 and dimedones 127 was developed by Hussain and Rao in 2021, allowing the synthesis of chromene scaffolds 128 in 40-82 % yield in the presence of commercially available silica nanocatalyst LUDOX HS-40 via a pot, atom, and step economic (PASE) assembly (Schemes 21, b).…”

Multicomponent synthesis of pyrrolo[2,1-a]isoindolylidene-malononitrile (PIYM) fluorophores and their photophysical properties

“…24–29 As a part of our research interests, our group is actively engaged in synthesizing hybrid building blocks to develop libraries of diverse bioactive small molecules through multicomponent reactions, incorporating the principles of diversity-oriented synthesis. 30–33…”

“…[24][25][26][27][28][29] As a part of our research interests, our group is actively engaged in synthesizing hybrid building blocks to develop libraries of diverse bioactive small molecules through multicomponent reactions, incorporating the principles of diversity-oriented synthesis. [30][31][32][33] Isoindoline derivatives are renowned for their chromophoric nature in several commercial dyes but are least exploited as fluorescent materials. [34][35][36][37][38][39][40] This might be due to the less available synthetic methodologies focused on improving the intramolecular charge transfer (ICT) of the isoindoline moiety with effectively extended conjugation.…”

Ethylenediamine Functionalized Cellulose Acetate [CAEDA] Nanosized Solid Base Catalyst in the Synthesis of 2‐Amino‐4H‐Chromenes and 5‐Substituted‐1H‐Tetrazoles

“…substituted 2-amino-4H-chromenes. [39][40][41][42][43][44][45][46][47][48][49][50][51][52] Very recent work has been done to synthesize Alkyl-4-(1H-indol-3 yl)-2-alkyl-4H-chromene-3-carboxylates using water extract of lemon [107] and is still in process but many of the protocols suffer from certain drawbacks such as tedious work-up, long reaction time, harsh reaction conditions etc. So, we present here the synthesis of 2amino-4H-chromenes using dimedone, different substituted aromatic aldehydes and malononitrile using ethanol as a solvent at 80°C in presence of Cellulose acetate [1,2-ethylenediamine][CAEDA] as a catalyst (Scheme 1).…”

“…Much research in context to synthesize this biological moiety viz . substituted 2‐amino‐4 H ‐chromenes [39–52] . Very recent work has been done to synthesize Alkyl‐4‐(1 H ‐indol‐3 yl)‐2‐alkyl‐4 H ‐chromene‐3‐carboxylates using water extract of lemon [107] and is still in process but many of the protocols suffer from certain drawbacks such as tedious work‐up, long reaction time, harsh reaction conditions etc.…”