Brønsted acid-catalyzed selective C–C bond cleavage of 1,3-diketones: a facile synthesis of 4(3H)-quinazolinones in aqueous ethyl lactate

Abstract

A facile and green approach was developed for the synthesis of 4(3H)-quinazolinones by using camphorsulfonic acid as a catalyst in an aqueous solution of biodegradable ethyl lactate. Various 2-aryl-, 2alkyl-, and 2-(4-oxoalkyl)quinazolinones were obtained by cyclization of 2-aminobenzamides with a wide range of acyclic or cyclic 1,3-diketones via C-C bond cleavage in satisfactory-to-excellent yields. Scheme 1. A green approach to 4(3H)-quinazolinones.

Organic Synthesis Using Environmentally Benign Acid Catalysis

“…Uozumi and co-workers showed that camphorsulfonic acid (CSA) can be used as efficient catalyst for the synthesis of 4( 3H )-quinazolinones [ 161 ]. The reaction used a water-ethyl lactate mixture as green solvent and was able to produce the desired compounds from a large variety of 2-aminobenzamides and 1,3-diketones (Scheme 70 ).…”

Bis(2-methoxyethyl)ether promoted intramolecular acceptorless dehydrogenative coupling to construct structurally diverse quinazolinones by molecular oxygen

“…12 In 2019, Tang & Pan's group developed an electrochemical cross-dehydrogenation coupling to construct CN double bonds for the synthesis of rutaecarpine alkaloids (Scheme 2b). 13 To continue our interest in ether/O 2 promoted oxidative cleavage, 8 N -heterocyclic synthesis, 14 and green organic synthesis, 15 we report here an intramolecular oxidative dehydrogenative coupling for the construction of dihydroisoquinolino[2,1- a ]quinazolinones, 2-aryl quinazolinones, and analogues promoted by bis(2-methoxyethyl)ether in the presence of molecular oxygen under clean conditions (Scheme 2c).…”

Ethyl lactate: An Efficient Green Mediator for Transition Metal Free Synthesis of Symmetric and Unsymmetric Azobenzenes

“…[3] It also has been fruitfully engaged in the extraction of various bioactive compounds and diverse food such as carotenoids, [4] polyphenols, [5] amino acids [6] and caffeine. [7] Besides, it has successfully being employed as a green solvent in a number of effective organic reactions [8] for the preparation of significant compounds such as spirooxindole-pyran derivatives, [9] 1,4-benzothiazines, [10] bis(Indolyl)methanes, [11] polyfunctionalized alkenes, [12] quinoxalines, [13] 4(3H)-quinazolinones, [14] 2-pyrazoline derivatives [15] and enaminones. [16] For a long period, aromatic azo-compound has received considerable amount of interest among the chemists.…”