Palladium-Catalyzed Synthesis of Phenanthridine/Benzoxazine-Fused Quinazolinones by Intramolecular CH Bond Activation

Regioselective synthesis of phenanthridine-fused quinazolinones using a 9-mesityl-10-methylacridinium perchlorate photocatalyst

Herein, we demonstrate a regioselective intramolecular C-N cross-coupling for the synthesis of 14H-quinazolino[3,2-f]phenanthridin-14-one by using 9-mesityl-10-methylacridinium perchlorate as the visible-light (450-470 nm) photocatalyst. The experiments with BHT, TEMPO, and Stern-Volmer quenching studies helped to rationalize a radical pathway via a SET mechanism.

Regiodivergent C-N Coupling of Quinazolinones Controlled by the Dipole Moments of Tautomers

Herein, we report that the dipole moments of tautomers can be the controlling factor for regiodivergent synthesis of either 14H-quinazolino[3,2-f]phenanthridin-14-ones or 6H-quinazolino[1,2-f]phenanthridin-6-ones, selectively, from unmasked 2-([1,1'-biphenyl]-2-yl)quinazolin-4(3H)-one. An intramolecular C(sp²)-NH coupling reaction mediated by PhI(OCOOCF₃)₂ could lead to two different regioisomers selectively at different temperatures when the dielectric constants of solvents like hexafluoroisopropanol and trifluoroacetic acid matched with the tautomer's dipole moments.

The Rh(iii)-catalysed C–H/N–H annulation of 2-thienyl- and 2-phenyl-quinazolin-4(3H)-ones with diphenylacetylene

2-Thienyl/phenyl substituted quinazolin-4(3H)-ones were converted into 4,5-diphenyl-7H-thieno[2′,3′:3,4]pyrido[2,1-b]quinazolin-7-ones or amide alcoholysis product via Rh(iii)-catalyzed reaction of with diphenylacetylene.

Rhodium(iii)-catalyzed annulation of 3-arylquinazolinones with alkynes via double C–H activation: an efficient route for quinolino[2,1-b]quinazolinones

An effective method for the synthesis of quinolino[2,1-b]quinazolinones has been described.

C–H functionalization of quinazolinones by transition metal catalysis

Quinazolinone and its derivatives are an important class of heterocyclic scaffolds in pharmaceuticals and natural products. This review provides the recent research advances in the transition metal catalyzed selective C–H bond functionalization of quinazolinone.

Palladium catalyzed chemo- and site-selective C-H acetoxylation and hydroxylation of oxobenzoxazine derivatives

An efficient protocol for the introduction of acetoxy and hydroxy functionalities on unactivated aryl sp2 carbons of oxobenzoxazine derivatives via an ortho-C-H activation reaction using a palladium catalyst has been developed for the first time. Interestingly, this intermolecular C-H functionalization reaction takes place in a facile and simple manner with high chemo- and site selectivity.

Ruthenium catalyzed chemo and site-selective C–H amidation of oxobenzoxazine derivatives with sulfonyl azides

A novel and general protocol towards the synthesis of highly functionalized ortho-amido oxobenzoxazine frameworks via ruthenium catalyzed intermolecular C–H amidation using sulfonyl azides as amidation components has been developed for the first time.

Direct diversification of unmasked quinazolin-4(3H)-ones through orthogonal reactivity modulation

Here we report a set of direct functionalization methods of unmasked 2-phenylquinazolin-4(3H)-ones, a privileged alkaloid core, without the installation/removal event of protecting groups or exogenous coordinating moieties. Divergent pathways were modulated with transition-metal catalysts by suppressing competitive reactivities, leading to N-arylation, annulative π-extension, or C-H fluorination.

Pd-Catalyzed regioselective C–H halogenation of quinazolinones and benzoxazinones

A Pd-catalyzed ortho-selective halogenation of benzoxazinone and quinazolinone scaffolds has been described employing N-halosuccinimide via C–H bond activation.

Visible-light-promoted synthesis of phenanthridines via an intermolecular isocyanide insertion reaction

An isocyanide insertion reaction promoted by the combination of an amide and a photoredox is now presented.