Microwave assisted synthesis of triazoloquinazolinones and benzimidazoquinazolinones

Abstract

Background

Synthesis, structure and some reactions of 4a',5′,6′,7′,8′,8a'‐hexahydro‐4′H‐spiro[cyclohexane‐1,9′‐[1,2,4]triazolo[5,1‐b]‐quinazolines]

“…During recent years, great interest was focused on [1,2,4]triazolo [5,1-b]quinazolines with different degrees of hydrogenation of the quinazoline moiety [7][8][9][10][11][12][13][14][15][16]. In many respects it is caused by the fact that the compounds containing annelated 1,2,4-triazole and quinazoline rings exhibit antihypertensive activity [14,15] and act as antagonists of adenosine [17,18] and nociceptin receptors [2].…”

“…From a variety of synthetic methods [7][8][9][10][11][12][13][14][15][16][19][20][21] the condensation of 3-substituted 5-amino-1,2,4-triazoles with aldehydes and 1,3-cyclohexandione or alkylideneand arylidenecyclohexanones [8,9,12,13,20] is the most appropriate way to synthesize partially hydrogenated [1,2,4]triazolo [5,1-b]quinazolines. These reactions allow to modify substituents at the positions 2 and 9 of the triazolo[5,1-b]quinazoline system.…”

“…For [1,2,4]triazolo [5,1b]quinazolines, oxidative aromatization of 9-(aryl)-6,6dimethyl-5,6,7,9-tetrahydro-4H- [1,2,4]triazolo [5,1-b]quinazolin-8-ones [13] and of 6,8,9-triphenyl-4,7,8,9-tetrahydro- [1,2,4]triazolo [5,1-b]quinazoline [10] was realized. However, hydrogenation of 6,8,9-triphenyl-4,7,8,9-tetrahydro-[1,2,4]triazolo [5,1-b]quinazoline by sodium borohydride was unsuccessful due to impossibility of rearrangement of this substance into imine tautomer necessary for reduction [10].…”

Rapid Solvent-Free Microwave Assisted Synthesis of Some N’-Benzylidene Salicylic Acid Hydrazides

“…Solvent free condition is especially suitable for microwave activation. Thus the use of microwave energy for the synthesis of organic compounds forms a part of green chemistry [2]. The feasibility of microwaveassisted synthesis has been demonstrated in various transformations like condensation [3], cycloaddition [4], synthesis of various heterocyclic compounds [5][6], and in many other chemical reaction.…”

Multicomponent reaction of benzyl halides: Synthesis of [1,2,4]triazolo/benzimidazolo quinazolinones

“…[20] Hence, the synthesis of quinazolinone has evoked much interest, as a result of which a variety of synthetic methodologies have been reported. [21][22][23] The most important approaches are (i) one-pot condensation of aromatic aldehydes, 2-amino benzimidazole/3-amino-1,2,4-triazole, and α-hydroxy C-H acids, [24] (ii) three-component reaction of 2-amino benzamides, aryl halides, and isocyanides, [25] (iii) one-pot reaction with o-amino benzamides and primary alcohols, [26] (iv) cascade synthesis of phenylamino substituted quinazolinones from urea derivatives and tert-butyl isocyanide, [27] [v] oxidative radical skeletal rearrangement induced by oxygen, [28] (vi) synthesis of quinazolinone and quinazoline from aerobic oxidative C(sp3)À H amination/ CÀ N cleavage. [29] Other methods have also been developed within the past three decades.…”