The Conversion of 4-Anilinoquinazoline- and 3-Aryl-4-imino-3,4-dihydro-quinazoline-2-carbonitriles into Benzo[4,5]imidazo[1,2-c]quinazoline-6-carbonitriles via Oxidative and Nonoxidative C–N Couplings

Abstract

Benzo[4,5]imidazo[1,2-c]quinazoline-6-carbonitriles are prepared in high yields via three new routes: (1) a Cu(OTf)2 (0-5 mol %) catalyzed hypervalent iodine [PhI(OTf)2] mediated oxidative coupling of 4-anilinoquinazoline-2-carbonitriles in neat trifluoroacetic acid (TFA); (2) a Pd(OAc)2 (10 mol %) or CuI (10 mol %) mediated nonoxidative coupling of 4-(2-bromoanilino)quinazoline-2-carbonitrile; and (3) a nonoxidative Pd(Ar3P)3 [Ar = 3,5-(F3C)2C6H3] [aka Superstable Pd(0) Catalyst] (10 mol %) mediated intramolecular C-N cyclization of 3-(2-bromophenyl)-4-imino-3,4-dihydroquinazoline-2-carbonitriles. All new compounds are fully characterized.

I2-Catalyzed Oxidative Cross-Coupling Reaction of Methyl Ketones and 2-(2-Aminophenyl) Benzimidazole: Facile Access to Benzimidazo[1,2-c]quinazoline

“…18 Later, Koutentis and co-workers reported Cu- and Pd-catalyzed oxidative and nonoxidative C–N coupling reactions to give the corresponding products in high yields (Scheme 1c). 19 Recently, Sarada et al established a nickel-catalyzed aerobic oxidative isocyanide insertion reaction for the synthesis of a novel benzimidazoquinazolines via sequential double annulation cascade protocol (Schemes 1d and 2). 20 All of the above reports suffer from drawbacks such as the use of prefunctionalized starting materials, harsh reaction conditions, longer reaction time, and metal catalyst.…”

Facile oxidation of alcohols to carboxylic acids in basic water medium by employing ruthenium picolinate cluster as an efficient catalyst

“…Benzoic acid and its derivatives are important precursors for the synthesis of useful organic compounds . Several hundred thousand tons of benzoic acid for industrial applications is produced every year .…”

An Efficient Synthesis of Pyrrolo[1,2‐a] or Pyrido[1,2‐a]benzo[4,5]imidazo[1,2‐c]quinazoline Derivatives in Ionic Liquids Catalyzed by Iodine

“…However, only a few reports concern about the synthesis of benzoimidazoquinazoline skeleton , which is a fused heterocycle containing both benzimidazole and quinazoline moieties in a molecule. As far as we know, there are few examples about the more complicated heterocyclic structures bearing benzoimidazoquinazoline as well as other heterocycles, such as pyrrole or pyridine, whereas they were catalyzed by costly Au or Pt catalyst using alkynol as a reactant.…”