Niacin as a Potent Organocatalyst towards the Synthesis of Quinazolines Using Nitriles as C–N Source

Abstract

An efficient and cost‐effective Vitamin‐B3‐catalyzed protocol towards the synthesis of diversely substituted quinazolines is illustrated using 2‐aminobenzylamines and nitriles as substrates. An organocatalytic transformation has been investigated where nitrile plays a role of C–N bond donor. The developed approach is applicable on a wide range of 2‐aminobenzylamines and nitriles for the synthesis of substituted quinazolines in high yields with a broad functional group tolerance.

Organocatalytic Decarboxylation and Dual C(sp3)−H Bond Functionalization Toward Facile Access to Divergent 2,6‐Diarylpyridines

“…With an objective of devising a coherent organocatalytic strategy for the decarboxylation of amino acids and C(sp 3 )−H bond functionalization of aromatic ketones toward the synthesis of pyridines, we began our explorations by choosing acetophenone ( 1 a ) and glycine ( 2 a ) as our model substrates. With the experience of working on the similar cores and organocatalysts, we initiated our experimental studies by screening established organocatalysts [2g,m–o] towards the effective conversion of acetophenone ( 1 a ) and glycine ( 2 a ) in to 2,6‐diphenylpyridine ( 3 aa ) (Table 1). To our surprise, all tested organocatalysts responded fairly under the reaction conditions by giving 2,6‐diarylpyridine ( 3 aa ) in yields ranging from 46–72% (Table 1, entries 1–5).…”

One‐Pot Synthesis of Quinazolines via Elemental Sulfur‐Mediated Oxidative Condensation of Nitriles and 2‐(Aminomethyl)anilines

“…Recently, quinazolines could be obtained efficiently under metal‐free conditions [16–21] . Furthermore, the synthesis of corresponding quinazoline derivatives by organocatalytic protocols has been reported [22–24] …”

Recent Advances in Pyridine‐Based Organocatalysis and its Application towards Valuable Chemical Transformations

“…Further oxidation of amine radical C in presence of B gives an imine intermediate D , which upon nucleophilic addition with 57 to furnish an amidine embedded imine intermediate E . At last, imine carbon undergoes nucleophilic addition with an amidine nitrogen resulting in intermediate F , which on dehydroamination yields the desired product 56 (Scheme ) …”