An alternative synthesis of pyrimido[4,5-b]quinoline-4-ones via metal-free amination in water and Vilsmeier–Haack cyclization

A New and Convenient Synthetic Method for 4-Aminoquinoline-3-carbonitrile and Its Derivatives

“…Because enaminonitriles are frequently used in ring construction, [16][17][18] their presence strongly suggests that 4-aminoquinoline-3-carbonitriles could be used to build larger polycyclic systems (PHCs). derivatives and quinolines via the intramolecular Friedel-Crafts reaction.…”

“…derivatives and quinolines via the intramolecular Friedel-Crafts reaction. [19][20][21][22] Worthy of note is that significantly more cyclization chemistry has been described for the isomeric 2-aminoquinoline-3-carbonitriles, 16,17 which has led to a number of patented biologically active compounds. 23,24 We recently developed a new route to 4-aminoquinoline-3-carbonitriles starting by cyanoethylation of 2-aminobenzonitrile to afford 2-((2-cyanoethyl)amino)benzonitrile, which can then be cyclized via base-assisted Thorpe-Ziegler cyclization to finally yield 4-aminoquinoline-3-carbonitriles.…”

One-pot multi-component synthesis of new bis-pyridopyrimidine and bis-pyrimidoquinolone derivatives

“…Therefore, considerable attention has been paid to develop novel approaches to the synthesis of heterocycles [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Among them pyridopyrimidine derivatives have attracted wide attention due to their broad biological activities including anticancer [ 23 ], antiviral [ 24 ], antiallergic [ 25 ], anti-HIV [ 26 ], anti-inflammatory [ 27 ], and antifolate [ 28 ] properties; and pyrimidoquinoline derivatives are of importance because of their interesting and diverse pharmacological properties; such as, antimicrobial, anti-inflammatory, anticancer [ 29 ], antiallergic [ 30 ], anti-HIV, antimalarial [ 31 ], and antibacterial [ 32 ] activities. Some biologically important pyridopyrimidines [ 33 ] and pyrimidoquinolines [ 34 ] are shown in Figure 1 .…”

Catalyst-Free, One-Pot, Three-Component Synthesis of Pyrimido[4,5-b] Quinoline-4-Amines under Microwave Irradiation

“…12 Several synthetic strategies have been developed for the preparation of pyrimido[4,5-b]quinolinones. [13][14][15][16][17] However, the scarce availability of starting materials, harsh reaction conditions and the tedious workup procedures are the main drawbacks of many of these methods. To overcome these difficulties, more efficient and convenient synthetic methodology is still required.In a continuation of our interest in new synthetic methodologies for fused quinolines, [18][19][20] herein we report the catalyst-free, one-pot, three-component synthesis of pyrimido [4,5-b]quinoline-4-amines 4 by the reaction of 2-aminoquinoline-3-carbonitrile 1, N,Ndimethylformamide dimethyl acetal (DMFDMA) 2 and primary amines 3 under microwave irradiation (Scheme 1).…”

“…12 Several synthetic strategies have been developed for the preparation of pyrimido[4,5-b]quinolinones. [13][14][15][16][17] However, the scarce availability of starting materials, harsh reaction conditions and the tedious workup procedures are the main drawbacks of many of these methods. To overcome these difficulties, more efficient and convenient synthetic methodology is still required.…”