Organocatalytic Synthesis of Fused Bicyclic 2,3-Dihydro-1,3,4-oxadiazoles through an Intramolecular Cascade Cyclization

Abstract

Hydrazone-carboxylic acids undergo intramolecular cyclization in the presence of pivaloyl chloride, iPr(2)NEt, and catalytic DABCO to form a range of substituted fused tricyclic 2,3-dihydro-1,3,4-oxadiazoles in high yields.

Mild and Versatile Potassium Fluoride/Tetrabutylammonium Fluoride Protocol for Ester Hydrolysis

“…7a, 7b, 7e, 7f, 7g, 7h, 7i, 7j, 7k and 7l) and the carboxylic acids (8a, 8b, 8e, 8f, 8g, 8h, 8i, 8j, 8k and 8l) mentioned in the Table-1 are commercially known compounds and are confirmed by matching with the authentic compounds. The esters 7c, 7d, 7m, 7n, 7o and the carboxylic acids 8c, 8d, 8m, 8n, 8o are reported in the literature [8][9][10][11][12][13][14][15][16] and are confirmed by matching the analytical data with the authentic compounds. Further the reaction was tried on p-nitromethyl benzoate (7a) in different solvents (Table-2) and the solvent THF was found the best in terms of time and yield of the reaction.…”

Synthesis of 3‐Indole Substituted Sulfonyl 4H‐Chromenes Using Recyclable Cyclometrix Polyphosphazene‐Base Catalysts

“…Heterocyclic motifs are ubiquitous throughout pharmaceutical and agrochemical industries [4,5] . The chromene core skeleton is one of the most privileged pharmacophores as it is able to interact with different kinds of cellular targets, [6–9] exhibiting a broad spectrum of significant biological activities [10] .…”

“…[2,3] Heterocyclic motifs are ubiquitous throughout pharmaceutical and agrochemical industries. [4,5] The chromene core skeleton is one of the most privileged pharmacophores as it is able to interact with different kinds of cellular targets, [6][7][8][9] exhibiting a broad spectrum of significant biological activities. [10] Among the derivatives of chromene motif, the 2amino substituted 4H-chromenes are known to possess several pharmaceutical activities such as anticancer, antifungal, antiinflammatory, antiviral, antitumor, antivascular, and anti-tubercular.…”

Mild and Efficient Synthesis of 5‐(2,2‐difluoro‐1‐phenyl cyclopropyl)‐N‐substituted‐1,3,4‐oxadiazol‐2‐amines via Graphene Oxide as Catalyst under Ultrasonic Irradiation Conditions

“…Heterocyclic motifs are ubiquitous throughout pharmaceutical and agrochemical industries, in which oxadiazole skeleton has attracted a major focus due to their wide range of interesting biological properties in the field of medicinal chemistry . Especially, 2‐amino substituted 1,3,4‐oxadiazoles have impacted numerous drug discovery programs, including anticancer,, anti‐inflammatory and anti‐proliferative, antimicrobial and cytotoxic, antiallergic, antibacterial, anti‐tubercular, antioxidant and antifungal activities .…”