Three-Component One-Pot Synthesis of New 2,5,6,7- and 2,5,8,10-Substituted Pyrimido[4,5-b]quinoline-4,6-diones and -2,4,6-Triones

Synthesis of pyrimido[4,5- b ]quinolindiones and formylation: ultrasonically assisted reactions

“…Then, adduct I undergoes cyclization through a Michael-type reaction with 6-aminopyrimidinone 1, leading to the formation of the corresponding three-cyclic compounds 4 and 5. These types of transformations have been previously studied and reported [16][17][18][19][20][21][22][23][24][25], and we have gained experience in this area [26,29,35]. Our results indicate that these MCRs follow a similar synthetic sequence, even with pyrazole nuclei [27,28].…”

“…Therefore, we decided to synthesize compounds 4 and 5 and isolate and purify them without characterization for further transformations. This work contributes to expanding the synthetic alternatives and molecular library of pyrimidoquinoline derivatives from a variety of aminopyrimidin-4-ones [16][17][18][19][20][21][22][23][24][25]. The synergy between acetic acid as a solvent, energy transfer agent and ultrasound radiation accelerated dehydration in the reaction.…”

“…Pyrimidoquinoline derivatives have been widely studied from several aspects, including synthetic procedures for obtaining detailed methodologies, reactions, precursors, catalysts, diversity, structural derivatization, analysis of biological activity and studies of potential applications as materials [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Convergent synthetic routes for the preparation of the pyrimido [4,5-b]quinoline template involved the construction of a pyrimidine ring on the pyridine core of the hydroquinoline ring.…”

“…MCRs, in combination with microwave-or ultrasound-assisted synthesis, have contributed to the expansion of the molecular library of pyrimido [4,5-b]quinoline derivatives (figure 1C) [8][9][10][12][13][14][15][16], resulting in molecules with significant properties [1][2][3][4][5][6][7][12][13][14][15][16]. These studies have led to the development of greener and environmentally safer synthetic conditions [17][18][19][20][21] and reusable catalysts [22][23][24][25] (figure 1D). Tricyclic pyrimido [4,5-b]quinoline derivatives are often synthesized by two methods: one based on a two-component reaction using the quinoline or hydroquinoline nucleus (figure 1A and B) and the other by MCRs (figure 1C and D).…”

Synthetic methodology of pyrimido[4,5‐b]quinoline derivatives

“…The reaction was carried out under reflux and ultrasonication, and the results were compared. It was found that the yields were improved by applying the ultrasound method (Scheme 23) [52, 53].…”