A Novel Ruthenium-Catalyzed Dehydrogenative Synthesis of 2-Arylquinazolines from 2-Aminoaryl Methanols and Benzonitriles

Abstract

By employing a commercially available Ru3(CO)12/Xantphos/t-BuOK catalyst system, a novel and straightforward ruthenium-catalyzed dehydrogenative synthesis of 2-arylquinazolines has been demonstrated. A series of 2-aminoaryl methanols were efficiently converted in combination with different types of benzonitriles into various desired products in moderate to good yields upon isolation. The synthetic protocol proceeds with the advantages of operational simplicity, high atom efficiency, broad substrate scope, and no need for the use of less environmentally benign halogenated reagents, offering an important basis for accessing 2-arylquinazolines.

Heterogeneous Palladium‐Catalyzed Hydrogen‐Transfer Cyclization of Nitroacetophenones with Benzylamines: Access to C−N Bonds

“…To gain insight into a possible mechanism for the formation of the quinazolines, several control experiments were conducted, as shown in Scheme . First, 3 a was not observed in the reaction of 6 a with 2 a′ over 4 h under the standard conditions (Scheme A) . Upon performing the reaction of 5 c with 2 a′ in the presence of a nitrogen source, 3 a was formed in 89 % yield (Scheme B).…”

Nickel‐Catalyzed Synthesis of Pyrimidines via Dehydrogenative Functionalization of Alcohols

“…In this regard, selective conversion/functionalization of cheap and abundantly available alcohols offers an elegant sustainable approach for the synthesis of various important organic compounds including pyrimidines and other organo‐heterocycles . This indeed uses our fossil carbon resources and can reduce CO 2 emission.…”

“…In recent years much research has been focused on developing new synthetic approaches for functionalization of alcohols to quinoline, quinazoline, quinazolin‐4(3H)‐one, pyrrole, pyrimidine, pyridine etc. Despite notable progress, most of these methods involve expensive and toxic heavier transition metals such as Ru or Ir as catalysts (Scheme ) . Therefore, to make these alcohol functionalization reactions more sustainable and economically affordable, the heavier metal catalysts need to be substituted by low‐cost and abundantly available first‐row base metal catalysts.…”

“…It is worth mentioning here that transition metal catalyzed functionalization of alcohols usually proceeds via initial dehydrogenation of alcohols to the corresponding carbonyl compounds followed by subsequent condensation, inter‐, or intramolecular cyclization steps . The first dehydrogenation step mostly goes via two‐electron hydride transfer pathway involving the formation of metal‐hydride intermediates .…”

Expeditious Synthesis and Spectroscopic Characterization of 2-Methyl-3-substituted-quinazolin-4(3H)-one Derivatives

“…For instance, quinazoline motifs have been reported to exhibit diverse biological and pharmacological activities which include anticonvulsant 9 , anti-inflammatory 10 , antileishmanial 11 , antimalarial 12 , antioxidant 13 , antitubercular 14 , antiviral 15 among others. Vast amount of literature has been documented for the synthesis of quinazoline and quinazolinone on the catalyst supported synthesis of this crucial heterocyclic core, some of which are Ceryl ammonium nitrate (CAN) for synthesis of 1 16 , Ru 3 (CO 2 ) 12 for 2 17 , CuCl for 3 18 , b-cyclodextrin/Montmorillonite for 4 19 , iodine for 5 20 and Fe/HCl for 6 21 ( Fig. 1).…”