Simple efficient synthesis of 4-aminoquinazoline via amidine of N-arylamidoxime

A Review on Current Synthetic Methods of 4-Aminoquinazoline Derivatives

Quinazoline scaffold and its various derivatives, as an important category of heterocyclic compounds, have received much attention for the design and development of new drugs due to their various pharmacological properties like anticancer, anticonvulsant, antidepressant, antibacterial, antifungal, antioxidant, anti-HIV, antileishmanial, anticoccidial, antimalarial, anti-inflammatory, antileukemic, and antimutagenic. Among the various substituted quinazolines, 4-aminoquinazoline scaffold, as a privileged structure in medicinal chemistry, is present in many approved drugs and biologically active compounds. Furthermore, 4-aminoquinazoline derivatives are often applied as key intermediates in the preparation of bioactive compounds. The current review focuses on the key methods for the preparation of 4-aminoquinazoline derivatives, including the nucleophilic substitution reaction, metal-catalyzed approaches, microwave irradiation methods, cyclocondensation, and direct amination methods.

I2/CuCl2-Copromoted Formal [4 + 1 + 1] Cyclization of Methyl Ketones, 2-Aminobenzonitriles, and Ammonium Acetate: Direct Access to 2-Acyl-4-aminoquinazolines

We herein report an I₂/CuCl₂-copromoted diamination of C(sp³)-H bonds for the preparation of 2-acyl-4-aminoquinazolines from methyl ketones, 2-aminobenzonitriles, and ammonium acetate. This reaction features operational simplicity, commercially available substrates, mild reaction conditions, and good functional group compatibility. Mechanistic studies indicate that CuCl₂ plays a pivotal role in this transformation. This study uses a methyl group as a novel input to construct 2-acyl-4-aminoquinazoline derivatives for the first time.

A convenient one-pot synthesis of N-substituted amidoximes and their application toward 1,2,4-oxadiazol-5-ones

The first direct one-pot approach for the synthesis of N-substituted amidoximes from secondary amides or the intermediate amides has been developed. Through the Ph₃P–I₂-mediated dehydrative condensation, a variety of N-aryl and N-alkyl amidoximes (R¹(C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> NOH)NHR², where R¹ or R² = aryl, alkyl, or benzyl) were readily afforded under mild conditions and short reaction times. The synthetic application of the obtained amidoximes has also been demonstrated through the formation of 1,2,4-oxadiazolones via base-mediated carbonylative cyclization with 1,1′-carbonyldiimidazole.

Ph₃P–I₂ mediated one-pot synthesis of N-substituted amidoximes via imidoyl iodide was developed. The synthesis of 1,2,4-oxadiazol-5-ones was also demonstrated.