Pyrimido[5,4-c]quinolines: Synthesis from 3,4-Di-functionallized Quinoline, Reactivity and Biological Activities.

Quinoline and pyrimidine moieties are ubiquitous components in both natural and synthetic compounds, showcasing diverse applications. The fusion of these well-known structures into hybrid molecules has garnered attention due to their intriguing biological properties. Particularly in the field of medicinal chemistry, numerous studies in the last decade have focused on pyrimido[5,4-c]quinoline ring systems (PyQs5,4-c).

Design, Synthesis, Characterization, QSAR, Docking, Anti-inflammatory and Analgesic Evaluation of Some New Phthalazinediones.

Background: phthalazine derivatives were reported to possess anticonvulsant , cardiotonic , antibacterial, analgesic , anti-inflammatory, and anti-microbial activity. In the current study, we applied the QSAR for prediction of newly phthalazinediones incorporating thioamide moiety aiming to reach a more potent anti-inflammatory and Analgesic agent.

Methods: Phthalazinediones 10-15 have been synthesized through condensation of dibenzobarallene 3 with thiosemicarbazides 4-8.

Synthesis and antioxidant activity of a novel series of pyrazolotriazine, coumarin, oxoazinone, and pyrazinopyrimidine derivatives.

A series of pyrazolotriazone derivatives 8-10 were obtained via coupling of 3-(3,5-dimethyl-1H-pyrazol-1-yl)-3-oxopropanenitrile (1) with 3-pyrazole diazonium chlorides 2-4, followed by heating of the formed hydrazones 5-7 in acetic acid, respectively. Moreover, coupling reaction of 1 with the aryl diazonium salts 15a-c afforded hydrazones 16a-c. Furthermore, treatment of 1 with 2-hydroxy-1-aldehydes 18-20 afforded the corresponding coumarins 21-23, respectively.

Synthesis, characterization and RHF/ab initio simulations of 2-amino-1,3,4-thiadiazole and its annulated ring junction pyrimidine derivatives.

Michael addition reaction of the 2-amino-1,3,4-thiadiazole to chalcone as biselectrophile afforded 5,7-diphenyl-6-[1,3-diphenylpropan-1-on-3-yl][1,3,4]thiadiazolo[3,2-a]pyrimidine (3) instead of 5,7-diphenyl-5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine (5) via further Michael addition at C5 in pyrimidine moiety. The structure 3 was established through the aspect of ab initio calculations, elemental analysis and spectral data.

Synthesis and antioxidant evaluation of some new pyrazolopyridine derivatives.

4,6-Dimethyl-1H-pyrazolo[3,4-b]pyridine-3-amine (1) was used as a key intermediate for the synthesis of imidazolopyrazole derivatives 7-11 upon interaction with 3-(2-bromoacetyl)-2H-chromen-2-one (2), 2-(benzothiazol-2-yl)-4-chloro-3-oxobutanenitrile (3), 2,3-dibromonaphthalene-1,4-dione (4), naphtha[2,3-b]oxirene-2,7-dione (5), 2,5-dichloro-3,6-dihydroxyhexa-2,5-diene-1,4-dione (6), respectively. Acetylation of 11 afforded the bis-acetyl 12. Also, the imidazolopyrimidine 15 was prepared via treatment of 1 with sodium 3,4-dioxo-3,4-dihydronaphthalene-1-sulfonate (13) in DMF followed by cyclization of the bis-pyrazolopyrimidine 14 with glacial acetic acid.

Synthesis and antioxidant evaluation of some new 3-substituted coumarins.

3-Acetylcoumarin (1) was utilized as a key intermediate for the synthesis of 2-aminothiazole derivative 3 via bromination of 1 to afford acetylbromide 2 followed by treatment with thiourea or via Biginelli reaction of 1. Treatment of 3 with 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde, 2-methyl-4H-benzo[d][1,3]oxazin-4-one, furo[3,4-b]pyrazine-5,7-dione or 2-methyl-5,6,7,8-tetrahydro-4H-benzothieno[2,3-d][1,3]oxazin-4-one afforded diazine derivatives 4-7. Also, pyridopyrimidine 8 was obtained via a one pot reaction of 6-aminothiouracil, p-chlorobenzaldehyde and 3-acetylcoumarin.

Synthesis, characterization, antioxidant and antitumor evaluation of some new thiazolidine and thiazolidinone derivatives.

2-(2-Cyano-acetylamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylic acid ethyl ester (2) was utilized as a key intermediate for the synthesis of thiocarbamoyl derivative 3 via its reaction with phenyl isothiocyanate. Treatment of 3 with chloroacetyl chloride afforded thiazolidin-5-one 4. Compound 7 reacted with different α-halo carbonyl compounds to give thiazolidine 8a,b, and thiazolidin-4-one derivatives 9.