Nickel‐Catalyzed Decarboxylative Cyclization of Isatoic Anhydrides with Carbodiimides: Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones

Abstract

In this study, a nickel‐catalyzed decarboxylative cyclization of isatoic anhydrides with carbodiimides was developed. This protocol realized the direct introduction of carbodiimides into heterocyclic compounds under an in situ generated Ni(0) complex. Synthetically, this methodology provides a simplified and secure new approach for the preparation of 2‐imino‐2,3‐dihydroquinazolin‐4(1H)‐ones. The control experiments and DFT theoretical calculations indicated that the Ni(0)‐catalyzed process is of central importance to the entire transformation.magnified image

Cascade Cross‐Coupling/Spirocyclization/Formal [4+2] Cycloaddition Reactions of 3‐(2‐Isocyanoethyl)Indoles with Aromatic Azides: Access to Polycyclic Spiroindolines Bearing A Pentasubstituted Guanidine Moiety

“…Based on the experimental results together with previous related reports, [17] we proposed a plausible mechanism for the formation of 6 . As shown in Scheme 3, [RhCp*Cl 2 ] 2 might first coordinate with isocyanide 4 a to afford the complex Int‐I , which further reacted with azide 5 a to give rhodium nitrene species Int‐II with the release of N 2 .…”

“…Substrate scope of organic azides. Based on the experimental results together with previous related reports, [17] we proposed a plausible mechanism for the formation of 6. As shown in preferred because the aryl group could stabilize the built-up negative charge on N2, but there was no such stabilization effect available on N1.…”

Metal-Free N–H/C–H Carbonylation by Phenyl Isocyanate: Divergent Synthesis of Six-Membered N-Heterocycles

“…Another method includes an earth metal-catalyzed (Lanthanum) reaction using phenyl isocyanate (Scheme b) . Also, a couple of methods were available involving a reaction of phenyl isocyanate to N -heterocycles. − Another promising synthetic approach involves phenyl isocyanate with isatoic anhydride in the presence of a transition metal catalyst (Scheme c). − In contrast, the direct C–H carbonylation process also emerged as a valuable method for N -heterocycle synthesis. Such transformations have been developed predominantly under transition metal-catalyzed conditions (Scheme d). − Additionally, reviewing many studies displays that there are only a few methods with different sources of carbonylating agents such as, DIAD, dioxazolone, and TFBen .…”

Convenient Novel Method to Access N-Benzylated Isatoic Anhydride: Reaction Behavior of Isatoic Anhydride with 4-Chlorobenzyl Chloride in the Presence of Bases

“…N-Alkylated and benzylated isatoic anhydride and their derivatives are the most expedient building blocks for the synthesis of numerous potent nitrogen-substituted heterocyclic compounds mainly N-substituted 4-hydroxyquinolinone esters, 1 acetylenic quinazolinones, 2 anthranilamides, benzodiazepinedione, 3 quinazolinone, 4 quinolone derivatives, 5 benzoazetinone, 6 N-sulfonyl-1,2,3-triazoles, 7 tryptanthrin, 8 and 2,3dihydroquinazolin-4(1H)-ones. 9 Therefore, in the global isatoic anhydride market, 30−40% isatoic anhydrides have been used as pharmaceutical and chemical intermediates. The isatoic anhydride derivatives find a variety of applications that include dyes, pigments, coupling agents, labeling, and functionalizing target materials.…”