Ketonic Mannich Bases Research Articles

Synthesis of novel Mannich bases and hybrid Mannich bases related to isoindolin‐1,3‐dione

AbstractTreatment of isoindolin‐1,3‐dione (1) with formalin and the appropriate amine or diamine afforded new N‐Mannich bases and bis‐(Mannich bases) 2 to 6. The use of the appropriate hydrazide or dihydrazide as the amine component in the Mannich reaction with 1 led to Mannich bases and bis‐(Mannich bases) incorporating a hydrazide moiety. The synthetic potential of sec‐Mannich bases as precursors in synthesis of hybrid Mannich bases incorporating 1 was described. The N‐alkylation of 1 with ketonic Mannich bases was investigated.

An efficient water-mediated synthetic route for the alkylation of heteroarenes

An efficient synthetic route has been described for the alkylation of 1$H$-indole, 1$H$-benzimidazole, and 1$H$-benzotriazole. This approach features the alkylation of heteroaromatics through in situ generated enones from ketonic Mannich bases under metal-free conditions. A series of alkylated heteroaromatics have been synthesized via the K10 catalyzed alkylation reactions of these heteroaromatics with a variety of ketonic Mannich bases. Environmentally benign K10 catalyst, water-mediated mild reaction conditions, and the efficient synthesis of alkylated products are the advantages of this alkylation method.

Novel Phenolic 1-aryl-3-arylamino-1-propanones: Synthesis and Characterization

Abstract A small collection of 1-aryl-3-arylamino-1-propanones having a phenolic moiety in their structure has been obtained by the replacement of the tertiary amino group in ketonic Mannich bases with (hetero)aromatic amines. The installment of the phenolic moiety took place either through the N-alkylation of 4-aminophenol with ketonic Mannich base hydrochlorides, or via amine exchange in ketonic Mannich bases derived from either 2′-hydroxyacetophenone or 4′-hydroxyacetophenone.

Palladium-Catalyzed Heck-Type Coupling via C–N Cleavage

A palladium-catalyzed Heck-type coupling method between arenes and ketone Mannich bases via C–N cleavage to synthesize chalcones is reported. This protocol offers good yields and tolerates a broad range of functional groups. Based on the extensive experimental data, we propose a plausible coulping mechanism.

Investigation of Some Mannich Bases Corrosion Inhibitors for Carbon Steel

The paper presents the results obtained when using two ketonic Mannich bases (BM1 and BM2) as corrosion inhibitors in saline (standard sea water-3.5% NaCl) for different types of steel, with various alloying elements. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitors efficiencies were evalued and the protection mechanisms were discussed.

ChemInform Abstract: Chemoselective Aminomethylation of Bifunctional Substrates: Carbonyl versus Phenolic Hydroxyl, Carbonyl versus Pyrazole and Pyrrole versus Phenolic Hydroxyl as Competing Activating Groups.

Chemoselectivity in the Mannich reaction for three different types of bifunctional substrates has been investigated. 1-Hydroxy-2-naphthalenylethanone affords either phenolic Mannich bases at high pH (free amines), or ketonic Mannich bases at low pH (amine hydrochlorides), whereas the use of N,N-dimethylmethyleneiminium chloride as a preformed dimethylaminomethylation reagent gave the phenolic Mannich base. 1-Aryl-3-(1H-pyrazol-1-yl)-1-propanones undergo aminomethylation at position 4 of the pyrazole ring, and not at the methylene group α to the carbonyl function, regardless of the reaction conditions. 4-(2,5-Dimethyl-1H-pyrrol-1-yl)phenol is aminomethylated chemoselectively on the pyrrole ring under mild reaction conditions.

Chemoselective aminomethylation of bifunctional substrates: carbonyl versus phenolic hydroxyl, carbonyl versus pyrazole and pyrrole versus phenolic hydroxyl as competing activating groups

Chemoselectivity in the Mannich reaction for three different types of bifunctional substrates has been investigated. 1-Hydroxy-2-naphthalenylethanone affords either phenolic Mannich bases at high pH (free amines), or ketonic Mannich bases at low pH (amine hydrochlorides), whereas the use of N,N-dimethylmethyleneiminium chloride as a preformed dimethylaminomethylation reagent gave the phenolic Mannich base. 1-Aryl-3-(1H-pyrazol-1-yl)-1-propanones undergo aminomethylation at position 4 of the pyrazole ring, and not at the methylene group α to the carbonyl function, regardless of the reaction conditions. 4-(2,5-Dimethyl-1H-pyrrol-1-yl)phenol is aminomethylated chemoselectively on the pyrrole ring under mild reaction conditions.

A Novel Antifungal Agent with Broad Spectrum: 1‐(4‐Biphenylyl)‐3‐(1H‐imidazol‐1‐yl)‐1‐propanone

A series of (1-substituted aryl)-3-(1H-imidazol-1-yl)-1-propanones was synthesized through the N-alkylation of imidazole with 3-dimethylamino-1-(substituted aryl)-1-propanone hydrochlorides (ketonic Mannich bases). A second series of N(1) -substituted imidazoles was obtained by the reduction of the carbonyl function of the imidazole-ketones in the previous series by means of NaBH(4) . All of the compounds were evaluated for antifungal activity against 16 strains of Candida, and 3-(1H-imidazol-1-yl)-1-(4-biphenylyl)-1-propanone emerged as a broad-spectrum antifungal agent. Several 3-(1H-imidazol-1-yl)-1-(2'-(substituted benzyl)oxyphenyl)-1-propanones were also active towards Candida kefyr.

N-Alkylation of benzimidazoles with ketonic Mannich bases and the reduction of the resulting 1-(3-oxopropyl)benzimidazoles

Abstract Benzimidazole, benzimidazoles diversely substituted at position 2, and 5,6-dimethylbenzimidazole have been alkylated at N 1 with ketonic Mannich bases derived from acetophenones, acetylnaphthalenes, 2-acetylthiophene and 1-tetralone to afford a series of novel 1-(3-oxopropyl)benzimidazoles. The reduction of these transamination products with NaBH4 in methanol produced the corresponding 1-(3-hydroxypropyl)benzimidazoles in excellent yields.

TERTIARY KETONIC MANNICH BASES AS CORROSION INHIBITORS FOR ALUMINUM DISSOLUTION IN ACIDIC SOLUTIONS

Aluminum corrosion rate was studied in the absence and presence of some tertiary ketonic Mannich bases in 2 M HCl solution, using weight loss and galvanostatic polarization techniques. The two methods gave similar results. The results showed that the inhibitor efficiency increases with increasing inhibitor concentration and decreases with increasing the temperature of the system. The adsorption of these Mannich bases on Al surface is found to obey Temkin's adsorption isotherm. Galvanostatic polarization studies showed that these compounds are mixed-type inhibitors. Some thermodynamic parameters were computed and discussed. Finally, the influence of the chemical structure of the tertiary ketonic Mannich bases on their inhibition efficiencies is discussed.

ChemInform Abstract: A New Heck Reaction Modification Using Ketone Mannich Bases as Enone Precursors: Parallel Synthesis of anti‐Leishmanial Chalcones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new Heck reaction modification using ketone Mannich bases as enone precursors: Parallel synthesis of anti-leishmanial chalcones

A new Heck-type reaction for the synthesis of chalcones has been established using Mannich bases as enone precursors. The novel reaction proceeds rapidly in air atmosphere under ligandless conditions and can be adapted for library synthesis in a parallel reactor station. Screening of the synthesized chalcones revealed N-{4-[(1E)-3-oxo-3-(3-pyridinyl)-1-propenyl]phenyl}benzamide (3f) to be a potent anti-leishmanial agent.

Synthesis and Reactivity of Mannich Bases. Part 17. Ketonic Mannich Bases Derived from 2,5‐Dimethylpiperazine.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Use of ?-(N,N-dialkylamino)Propiophenones in the Synthesis of Nitrogenated Heterocyclic Compounds

β-(N,N-dialkylamino)propiophenones (ArCOCHR1CH2NR2) are compounds with special synthetic interest not only because many of them are biologically active, but also because they posses two different electrophilic reaction centers (i. e. carbonyl group and the β-carbon atom), which can be attacked by ambifunctional nucleophilic reagents. This property makes them attractive starting materials in medicinal chemistry as valuable building blocks for ring closure reactions to form mainly five, six and seven-membered heterocyclic compounds. Additionally, the presence of α-methylene active hydrogen atoms in such compounds also opens new possibilities for ring closure reaction as recently has been published. A selection of representative examples about structural and biological properties of the title compounds, synthetic methods and ring closure reactions leading to nitrogenated heterocyclic systems are described in this review. Keywords: mannich type reactions, aminomethylation, ketonic mannich bases, unsaturated ketones, heterocyclizations

Reactions of Ketonic Mannich Bases with Malononitrile and Malononitrile Dimer.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reactions of Ketonic Mannich Bases with Malononitrile and Malononitrile dimer

The reaction of malononitrile with the tertiary Mannich base hydrochloride derived from acetophenone and some related compounds 1, 3, 5 and 7, in piperidine at 50°C afforded the pyrido[1,2-a]pyrimidine derivatives 2, tetrahydronaphthalene derivative 4 substituted quinolines 6 and benzopyran derivatives 8. While the condensation of malononitrile dimer with acetophenone, cyclohexanone and/ or α-tetralone Mannich bases hydrochloride 1, 3 and 9 gave the pyridine, isoquinoline and benzo[f]isoquinoline derivatives 10–12 in moderate to good yield.

ChemInform Abstract: A Selective Method for 3‐Monoalkylation of 4‐Hydroxypyran‐2‐ones and of 4‐Hydroxyquinolin‐2(1H)‐ones or Their N‐Methyl Derivatives by Ketone Mannich Bases.

AbstractRegioselective C‐monoalkylation of the pyranone (I) with the Mannich bases (II) gives the oxoalkyl pyranones (III), which exist in solution in equilibrium with their hemiacetals (IV).

Synthese von 2‐Amino‐3‐nitropyridinen und ‐1,4‐dihydropyridinen

Synthesis of 2‐Amino‐3‐nitropyridines and ‐1,4‐dihydropyridinesThe title compounds 4 and 5 can be synthesized from the primary nitroketene animal 2 and 1,3‐biselectrophiles like β‐aminoketones (ketonic Mannich bases) or enaminoketones.

Alkylation of 4-Hydroxycoumarins by Ketone Mannich Bases. Synthesis of 4-Hydroxy-2-oxo-3-(3-oxoalkyl)-2H-1-benzopyrans

Alkylation of 4-Hydroxycoumarins by Ketone Mannich Bases. Synthesis of 4-Hydroxy-2-oxo-3-(3-oxoalkyl)-2<i>H</i>-1-benzopyrans

Interaction of Mannich bases with triethyl phosphite

A study of the kinetics of the reaction of aliphatic ketone Mannich bases with acetic acid indicated that this reaction is a reaction of elimination of vinyl ketone from a salt of the base with the acid and is a first-order reaction.