Preparation Of Pyrido Research Articles

Microwave‐supported synthesis of pyridocarbazoles

AbstractWe developed a microwave‐assisted preparation of pyrido[2,3‐c]carbazole from 3‐amino‐9‐ethylcarbazole. The use of microwave heating resulted in shorter response times and higher yields. This process is atom‐efficient and can be used in a variety of multi‐component reactions.

KF/Clinoptilolite Nanoparticles as a Heterogeneous Catalyst for Green Synthesis of pyrido[2,1-a]isoquinolines using Four-Component Reaction of Alkyl Bromides.

KF/Clinoptilolite nanoparticles are employed as a heterogeneous catalyst for the preparation of pyrido[2,1-a]isoquinoline derivatives through a four-component reaction of isoquinoline, two different alkyl bromides and an electron deficient internal alkynes at ambient temperature in water as green solvent. In this research, (2,2-Diphenyl-1-picrylhydrazyl) radical trapping and reducing potential of ferric ion experiments was used for determining antioxidant activity of some newly synthesized compounds such as 5a, 5c, 5f and 5g and comparing results with synthetic antioxidants (TBHQ and BHT). Compounds 5a, 5c, 5f and 5g display trace DPPH radical trapping and excellent reducing power of ferric ion. Furthermore, the power of some prepared compounds against Gram-positive and Gram-negative bacteria was proved by employing the disk dispersion experiment. The obtained results of disk diffusion test showed that compounds 5a, 5d and 5e prevented the bacterial growth. The reported procedure shows the advantages of clean reaction, high yield and simple purification.

Synthesis and Application of Imidazolium-Based Ionic Liquid Supported on Hydroxyapatite Encapsulated γ-Fe2O3 Nanocatalyst in Preparation of Pyrido[2,3-d]Pyrimidines

Synthesis of novel 2-amino-5-aryl-7-(1-methyl-1H-pyrrol-2-yl)-4-oxo-3,4,5,8-tetrahydro-pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives is reported by the reaction of 2,6-diaminopyrimidin-4(3H)-one, 3-(1-methy-1H-pyrrol-2-yl)-3-oxopropane nitrile and aryl aldehydes in the presence of newly synthesized imidazolium based ionic liquid supported on hydroxyapatite encapsulated γ-Fe2O3 nanocatalyst [γ-Fe2O3@HAp-Si(CH2)3Cl@DMIM] in short reaction times (7-13 min) and high to excellent yields (80%–95%). Cleaner reaction profile, mild reaction conditions, use of the green solvent and reusability of the catalyst, make this protocol attractive for the large scale synthesis of pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives and is amenable for iterative combinatorial library generation. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive analysis of X-rays, thermogravimetric analysis, differential thermogravimetric and vibrating sample magnetometer.

Preparation of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazene as a Fe3+ ion fluorescent sensor

A highly efficient coupling reaction of N-heterocyclic carbene precursors with sulfonyl azides has been developed, affording a variety of pyrido[1,2-c][1,2,4]triazole-based π-conjugated triazenes. The present reaction proceeds under very mild conditions with good functional group tolerance. The resulting triazenes exhibit selective and sensitive fluorescent response toward Fe3+ ion.

Preparation of Pyrido[2,3‐b]indole Derivatives Using Silicates of Group 1 and 2 Metals

An efficient synthesis of 2,4‐diaryl‐9H‐pyrido[2,3‐b] indole derivatives in aqueous medium via the three‐component reaction of indolin‐2‐one, a chalcone and ammonium acetate was developed using Na2SiO3, K2SiO3, Li2SiO3, CaSiO3, MgSiO3, BaSiO3, SrSiO3, and ZnSiO3 as catalysts. Results of activity evaluations indicated that among of the metal silicate used alkali metal silicates exhibits much higher activity than other samples due to the stronger basicity power and higher solubility in water. Under the optimum reaction conditions, all of the reactions with diverse aromatic aldehydes provided high yields in low reaction times.

Preparation of Pyrido[3,4-d]azepines by Pyridine Ring Heteroannulation

Preparation of Pyrido[3,4-d]azepines by Pyridine Ring Heteroannulation

ChemInform Abstract: Synthesis of Pyrido[1,2‐a]benzimidazoles Through a Copper‐Catalyzed Cascade C—N Coupling Process.

A simple and efficient method for the preparation ofpyrido[1,2-a]benzimidazoles by a copper-catalyzed inter- and intramolecular C–N coupling cascade process was designed and carried out, and the products were obtained in moderate to excellent yields (up to 93 %).

Synthesis of Pyrido[1,2‐a]benzimidazoles through a Copper‐Catalyzed Cascade C–N Coupling Process

AbstractA simple and efficient method for the preparation ofpyrido[1,2‐a]benzimidazoles by a copper‐catalyzed inter‐ and intramolecular C–N coupling cascade process was designed and carried out, and the products were obtained in moderate to excellent yields (up to 93 %).

ChemInform Abstract: A Novel Entry to Pyrido[4,3-b]carbazoles: An Efficient Synthesis of Ellipticine.

Abstract The palladium catalyzed tandem cyclization–cross-coupling reaction of indolylborate (2) with vinyl bromide (9) was developed for the preparation of pyrido[4,3-b]carbazole as a key reaction. The cross-coupling reaction of 2a provided hexatriene (10), and then cyclization of 10 to pyrido[4,3-b]carbazole (12) was effected with irradiation or Lewis acid. Using indolylborate (2c) for the cross-coupling reaction, a novel construction of ellipticine was attained through similar reaction sequences.

β-Aminocrotononitrile in heterocyclic synthesis: Synthesis of polysubstituted pyridines as precursors to bicycles and polycycles

β-aminocrotononitrile (1) reacted with either cyanothioacetamide to give (3) or malononitrile to afford an anion (5). Pyridine-2(1H)-thione (4) was obtained by boiling of (3) in ethanol and Et 3N or treatment of (5) with H 2S, respectively. The reaction of anion 5 with isothiocyanates (6) gave N-substituted pyridine-2(1H)-thiones (7). N-Substituted pyridine-2(1H)-thiones (7) can be used for the preparation of pyrido[2,3-d]pyrimidines (8a–e) and (10a–e), or the preparation of pyrido[1,2-a]pyrimidines (12a–d). 1,8-Naphthyridine derivatives (14a–d) and (16a–e) can also be obtained from pyridine-2(1H)-thione (7). Finally, 1,8-naphthyridine derivatives (16a–e) can be used for the preparation of tetracyclic compounds 17a–c and 18a,b.

Derivatives of pyrido[3´,2´:4,5]pyrrolo[1,2-c]pyrimidones

Different N-protected dichloromethanimines have been used for the preparation of pyrido[3 ,2 :4,5]pyrrolo[1,2-c]pyrimidines and the results are compared. The preparation of 4chloro-9-tosylaminopyrido[3 ,2 :4,5]pyrrolo[1,2-c]pyrimidine is described.

An Improved Synthesis of 5-(2,6-Dichlorophenyl)-2-(phenylthio)-6H-pyrimido[1,6-b]pyridazin-6-one (a VX-745 analog)

An improved procedure for the synthesis an analog of the p38 inhibitor compound VX- 745 is reported.

ChemInform Abstract: Preparation of New Pyridoacridine Derivatives and Formal Synthesis of 11-Hydroxyascididemine.

Abstract The preparation of pyrido[2,3,4-kl]acridin-6-ones substituted at position 4 following our previous methodology is described. A new synthetic route for the preparation of aminopyridoacridone 16, used before for the synthesis of the 11-hydroxyascididemine, is described. The cytotoxic activity of pyridoacridones 19 and 20 in four cell lines is reported.

Preparation of New Pyridoacridine Derivatives and Formal Synthesis of 11-Hydroxyascididemine

The preparation of pyrido[2,3,4-kl]acridin-6-ones substituted at position 4 following our previous methodology is described. A new synthetic route for the preparation of aminopyridoacridone 16, used before for the synthesis of the 11-hydroxyascididemine, is described. The cytotoxic activity of pyridoacridones 19 and 20 in four cell lines is reported.

ChemInform Abstract: A One‐Step Preparation of Pyrido(3,4‐d)pyrimidine Ring System by Reaction of 5‐Formyl‐1,3,6‐trimethylpyrimidine‐2,4(1H,3H)‐dione (I) with Primary Amines (II).

ChemInform Abstract: A One‐Step Preparation of Pyrido(3,4‐d)pyrimidine Ring System by Reaction of 5‐Formyl‐1,3,6‐trimethylpyrimidine‐2,4(1H,3H)‐dione (I) with Primary Amines (II).

Preparation of pyrido[3,4‐f]‐1,4‐oxazepines O → N smiles rearrangement in 4‐substituted 3‐benzoylpyridines

AbstractPreferential attack of mixed N,O‐dinucleophiles on 3‐benzoyl‐4‐chloropyridine (2) through the hydroxy function is achieved applying the potassium fluoride‐alumina reagent. This selectivity presents a route to pyrido[4,3‐b][1,5]benzoxazepines 5 and pyrido[3,4‐f]‐1,4‐oxazepines 12. O→N Smiles rearrangement in the intermediate 4‐(2‐aminophenoxy)‐ and 4‐(2‐aminoethoxy)‐3‐benzoylpyridines 4 and 10, respectively, is studied.

A one‐step preparation of pyrido[3,4‐d]pyrimidine ring system by reaction of 5‐formyl‐1,3,6‐trimethyl‐pyrimidine‐2,4(1H,3H)‐dione with primary amines

Abstract6,7‐Dihydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones were obtained in high yields from the reaction of 5‐formyl‐1,3,6‐trimethylpyrimidine‐2,4(1H,3H)‐dione (1) and primary amines. For this pyridopyrimidine synthesis the following reaction pathway is proposed; the [1,5]‐hydrogen shift of 1 gives a 5,6‐dihydro‐5,6‐dimethylenepyrimidine‐2,4(1H,3H)‐dione intermediate. The cycloaddition reaction of the intermediate with aldimines from 1 and the primary amines affords 5,6,7,8‐tetrahydropyrido[3,4‐d]pyrimidine‐2,4(1H,3H)‐diones, which are dehydrated to the final products.

ChemInform Abstract: Nitrogen‐bridged Heterocycles. Part 5. Preparation of Pyrido‐ and Azepino‐fused Cycl[3.2.2]azines.

AbstractThe title compounds (V) are obtained from the reaction of electron‐deficient alkynes (IV) with the heterocycles (IIc).

Preparation of Pyrido- and Azepino-fused Cycl[3.2.2]azines

Abstract Pyrido- and azepino-fused cycl[3.2.2]azines were obtained by the reaction of the corresponding pyrido- and azepino[hi]indolizines with electron-deficient acetylenes in the presence of appropriate oxidants. The reaction pathway of their preparation was proposed to be a sequence of Michael addition of indolizine to acetylene, 10π-electrocyclic reaction of Michael adduct, and dehydrogenation by means of the chemical conversions of the isolated intermediates.

ChemInform Abstract: Preparation of Pyrido[1 ,2‐a]pyrimidine Derivatives by Electrochemical Way. Part 1. Dimerization of 2,6‐Dimethyl‐3‐ethyl‐4‐oxo‐4H‐pyrido[1,2‐a]pyrimidine.

AbstractDurch elektrochemische Dimerisierung wird aus dem Pyridopyrimidin (I) die Verbindung (II) erhalten.