Regioselective four-component synthesis of new tetrazolo[1,5-a]quinoline-based 2-amino-1,4-dihydropyridine and pyridin-2(1H)-one derivatives using nano-ZnO catalysis

Abstract

Four-component reaction between primary amines, dialkylacetylendicarboxylates, tetrazolo[1,5-a] quinoline-4-carbaldehyde and ethyl-2-cyanoacetate in the presence of 1,4-diaza-bicyclo[2.2.2]octane and zinc oxide nanoparticles results to the regioselective production of new tetrazolo[1,5-a]quinoline-based 2-amino-1,4-dihydropyridine or pyridin-2(1H)-one derivatives in good to high yields. The selectivity of the catalyzed reaction toward the generation of the dihydropyridine or pyridin-2(1H)-one derivatives was found to be strongly dependent on the size of the alkyl groups in the ester moieties of the acetylenic esters. According to single-crystal X-ray diffraction and NMR studies, the pyridin-2(1H)-one derivatives involve a restricted rotation around the C-C bond connecting the tetrazoloquinoline and dihydropyridinone cyclic systems.

Use of Dialkyl Acetylenedicarboxylates in the Multicomponent Synthesis of Heterocyclic Structures

“…Thus, the best result was detected using in 100 mol % of DABCO in 20 mol % of ZnO NPs in ethanol under reflux condition (Scheme 40). [69] …”

“…Thus, the best result was detected using in 100 mol % of DABCO in 20 mol % of ZnO NPs in ethanol under reflux condition (Scheme 40). [69] In 2019 Pawar and co-workers accomplished synthesis of polysubstituted dihydropyridine derivatives 102 in presence of morpholine as an efficient organobase catalysis. The product synthesized via one-pot four component reaction of aldehydes 6, amines 2, dialkyl acetylene dicarboxylates 1 and acidic active methylene compound 101 at ambient temperature.…”

Chemistry of Quinoline Based Heterocycle Scaffolds: A Comprehensive Review

“…Tooran Aghaalizadeh et al . reported a method for synthesis of the tetrazolo[1,5‐a] quinoline based 2‐amino‐1,4‐dihdropyridine or pyridin‐2‐(1H)‐one derivatives (208,209) by reacting primary amine (204) , dialkylacetylendicarboxylates (205) , ethyl‐2‐cyanoacetate (206 ) and tetrazolo[1,5‐a]quinoline‐4‐carbaldehyde (207) in the presence of DABCO(1,4‐diaza‐bicyclo[2.2.2]octane and nanoparticles of ZnO with refluxing for 1 h [56] . (Scheme 41 )…”