Metal-free oxidative cyclization of 2-amino-benzamides, 2-aminobenzenesulfonamide or 2-(aminomethyl)anilines with primary alcohols for the synthesis of quinazolinones and their analogues

Efficient Synthesis of Quinazolinones by Transition‐Metal‐Free Direct Aerobic Oxidative Cascade Annulation of Alcohols witho‐Aminoarylnitriles

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Am ild and atom-economic method was developed for direct and efficient synthesis of quinazolinones through at ransitionmetal-free aerobic oxidativec ascade annulation reaction of widely available o-aminoarylnitriles and alcohols. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Among the methods reported, annulation reactions of o-aminoaryl acids and derivatives may be the most employed strategies, which include the condensation of o-aminoaryl acids with amides, nitriles, or acidd erivatives with an itrogen source (Scheme 1A), [2,3] the dehydrogenative or oxidative annulation of o-aminoarylamides with aldehydes, [4] masked aldehydes, [5] ketones, [6] imines, [7] or amines [8] (Scheme 1B), the carbonylative annulation of o-aminoarylamides with aC Os ource and aryl halides( Scheme 1C), [9] and the annulation of o-aminoarylnitriles with acid derivatives, [10] aldehydes, [11] or ketones [12] (Scheme 1D). Possibly owing to the "cesium effect", the water-soluble base CsOH was found to be crucial in all key steps of the reactionm echanism.B ecause a wide range of substrates can be used to prepare substituted quinazolinones withoutc ontamination by transition-metal residues, this method mayb eo fi nterestf or application in pharmaceutical synthesis.

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“…above-mentioned aldehydes, aldehydee quivalents, or acid derivatives in annulation reactions of o-aminoarylamides through transition-metal-catalyzed dehydrogenative, [16] oxidative, [17] or aerobic oxidative [18] strategies (Scheme 1F)h as also aroused much interest in recent years. Similarly,t he reactions of alcohols with o-nitroarylamides [19] or o-nitroarylnitriles [20] were also described recently.A lthough variousq uinazolinones and derivatives can be obtained by the above-mentioned methods, many still have inherent drawbacks that are difficult to overcome.…”

“…Similarly,t he reactions of alcohols with o-nitroarylamides [19] or o-nitroarylnitriles [20] were also described recently.A lthough variousq uinazolinones and derivatives can be obtained by the above-mentioned methods, many still have inherent drawbacks that are difficult to overcome. For example, some require tedious multistep procedures, [2,3] rather harsh reaction conditions, [2,3,19,20] transitionmetal catalysts or ligands [4-9, 11,13, 16] that can lead to metal residues in the products and limit their applicationsi nd rug synthesis, or excessa mounts of bases, [10,13] oxidants, [5,8,17] or reactants [19,20] that can lead to production of large amounts of wastes. Therefore, the development of direct, efficient, atomeconomic,a nd transition-metal-and waste-free methods that employ greener substrates and O 2 or even air as the oxidant remains of great importance.…”

An Aqueous Facile Synthesis of 2,3-Dihydroquinazolin-4(1H)-One Derivatives by Reverse Zinc Oxide Micelles as Nanoreactor

“…The preferable route is to directly catalyze the condensation of anthranilamide with aldehydes for target products (Xing et al, 2017). However, most of these approaches are associated with numerous limitations including complicated reactions, vast excess of oxidant, non-renewable solvents, harsh reaction conditions (such as temperatures of up to 100 • C), long reaction time and low reaction yields (Bie et al, 2016;Parua et al, 2017;Sun et al, 2018;Wang et al, 2018). In recent years, the focus has been on the development of economical and convenient methods for the synthesis of dihydroquinazolin-4(1H)-one derivatives via a tolerable approach (Tamaddon and Kazemivarnamkhasti, 2016;Liu et al, 2018).…”

Quinazolin-4(3H)-ones and 5,6-Dihydropyrimidin-4(3H)-ones from β-Aminoamides and Orthoesters

“…Along a different line, two separate reports detailed the synthesis of quinazolinones by oxidative cyclization of aldehydes with 2-aminobenzamide under aerobic conditions [ 6 ] and in the presence of tert -butyl hydroperoxide (TBHP)-potassium iodide [ 21 ]. A similar oxidative condensation of primary alcohols with 2-aminobenzamide to generate quinazolinones was promoted by TBHP alone [ 22 ] and together with iodine and dimethyl sulfoxide [ 23 , 24 ]. Numerous metals such as manganese [ 25 ], iron [ 26 ], nickel [ 27 ], zinc [ 28 ], ruthenium [ 29 ], iridium [ 30 ], and platinum [ 31 ] in conjunction with TBHP were also reported to promote this reaction.…”