Cobalt-Catalyzed Tandem Transformation of 2-Aminobenzonitriles to Quinazolinones Using Hydration and Dehydrogenative Coupling Strategy

Abstract

A tandem synthesis of quinazolinones from 2-aminobenzonitriles is demonstrated here by using an aliphatic alcohol–water system. For this transformation, a cheap and easily available cobalt salt and P­(CH2CH2PPh2)3 (PP3) ligand were employed. The substrate scope, scalability, and synthesis of natural products exhibited the vitality of this protocol.

Cobalt Catalyzed N‐Methylation of Amides using Methanol

“…In 2017, Liu and co‐workers first reported, cobalt catalyzed C‐methylation and N‐methylation reactions using methanol by introducing a [Co]/PP 3 (PP 3 = tris [2‐(diphenylphosphino)ethyl]phosphine) system [4a,b] . Using [Co]/PP 3 catalytic system, we recently reported direct synthesis of N‐methylated amides and quinazolinones by employing H 2 O/ROH from nitriles and 2‐aminobenzonitriles, respectively [4c,5] . Cobalt catalyzed numerous transformations using alcohol also explored in the recent years [3a] .…”

Recent Progress in the Synthesis of Heterocycles through Base Metal‐Catalyzed Acceptorless Dehydrogenative and Borrowing Hydrogen Approach

“…Several naturally occurring alkaloids and bio-active compounds contain quinazolinone (73) scaffolds, [76] which encourage chemist to develop new strategies to synthesize this heterocycle. [77][78][79] In 2017, Paul and co-workers [77] envisioned that quinazolinones (73) could be synthesized via acceptorless dehydrogenative coupling of 2-aminobenzamide (72) with various benzyl alcohols. They utilized square planar Ni(II) complex ([Ni(MeTAA)]) (Ni-2) in association with NaOtBu (1.1 equiv.)…”

“…In the same year, an inexpensive and widely abundant Co‐catalyzed synthesis of quinazolinone ( 73 ) has been introduced by Kundu and co‐workers [78] . 2‐aminobenzonitrile ( 75 ) reacted well with an array of various aliphatic alcohols (Scheme 32) to afford the desired product.…”

Synthesis of Quinazolinones Via a Tandem Hydrogen-Transfer Strategy Catalyzed by N,S Co-doped Carbon-Anchored Co Nanoparticles

“…A variety of synthetic strategies for quinazolinone skeleton construction have been disclosed. The representative synthetic methods are as follows (Scheme a–d): (a) the condensation reactions of 2-aminobenzamides with aldehydes − or carboxylic acids, (b) the coupling reactions of 2-haloarylamides with benzylamines, nitriles, , or aldehydes, (c) the annulation reactions of 2-aminoarylnitriles with carboxylic acids, aldehydes, ketones, or other similar reactants, − and (d) the acceptor-less dehydrogenation coupling or hydrogen-transfer reactions of benzyl alcohols with 2-aminobenzonitrile, 2-aminobenzamide, or 2-nitrobenzamide. − …”

“…Various transition metal-based catalysts including Ni, Fe, − Pt, Pd, Co, Au, Mn, and Cu , have been reported for the synthesis of quinazolinones through the abovementioned synthesis strategies. For example, Song et al developed a Ni 2 P@NPC-800 catalyst for aerobic cross-dehydrogenative coupling of alcohols with 2-aminobenzamides .…”