Conditions Of Basic Catalysis Research Articles

SUBSTITUTED AMINOCHALCONES AS STARTING COMPOUNDS FOR RECEIVING NEW 1,4-BENZODIAZEPINES DERIVATIVES

The aim of this work is the synthesis of a number of substituted E‑1-(2-amino‑5-R1-phenyl)-3-(4-R2-phenyl)prop‑2-en‑1-ones (2-aminochalcones) as precursors for obtaining new derivatives of 7-R1–5-[2-R2-phenylvinyl]-1,4-benzodiazepin‑2-ones. Starting 5-substituted 2-aminoacetophenones with bromo and nitro group were synthesized from 2-aminoacetophenone by bromination of the latter with N‑bromosuccinimide in acetonitrile and nitration of 2-acetaminoacetophenone with a nitrating mixture followed by removal of acetyl protection. 2-Aminochalcones were synthesized according to standard methods during the interaction of a number of 5-substituted 2-aminoacetophenones with para-substituted benzaldehydes under basic catalysis conditions. The target products turned out to be brightly colored compounds with low melting points, their isolation and purification did not cause any difficulties. According to the data of 1H NMR spectroscopy, all synthesized 2-aminochalcones were individual trans isomers, which was also confirmed by X‑ray structural analysis of one of the obtained 2-aminochalcones. A number of new substituted E‑1-(2-amino‑5R1-phenyl)-3-(4-R2-phenylprop‑2-en‑1-ones) were synthesized – compounds with amino and ketofunctions and are precursors for obtaining of a new series of 5-substituted 1,4-benzodiazepines with various arylvinyl groups. 2-aminoacetophenone, 2-amino‑5-bromoacetophenone, and 2-amino‑5-nitroacetophenone were selected as substrates for this series. The methyl groups of these acetophenones were condensed according to Claisen-Schmidt with parasubstituted benzaldehydes. Condensation was carried out under alkaline conditions in an aqueous solution. Yields of aminochalcones reached 60–85%. The methyl group of 2-aminoacetophenones smoothly reacted with aromatic aldehydes to form the corresponding 2-aminophenylchalcones. The structure of the obtained compounds was confirmed by mass spectrometry and 1H NMR spectroscopy. The structure of one of the chalcones was proved by X‑ray structural analysis. The obtained compounds can be used for the synthesis of 1,4-benzodiazepines with 5-arylvinyl substituents.

Synthesis of 6-Bromo-3a,4-dihydrobenzo[f]isoindolinium Bromides and Their Aqueous-Alkaline Cleavage

Cyclization of allyl[3-(4-bromophenyl)prop-2-ynyl]ammonium bromides under basic catalysis conditions, unlike their propargyl analogs, occurs under heating of the reaction mixture at 90–92°C. Cyclization, which is the main reaction route, is accompanied by rearrangement-cleavage to form 1-allyl-p-bromocinnamaldehyde. A favorable effect of the substituents on the nitrogen atom and the presence of the bromine atom in the 4 position of the aromatic ring on the cyclization and rearrangement-cleavage reactions is established.

Synthesis and Structure of 3-Aryl-2,4-dibenzoyl-5-hydroxy-5-methylcyclohexanones and 2-Benzoyl-5-hydroxy-5-methyl-3-phenylcyclohexanone

The reaction of benzoylacetone with aromatic aldehydes under basic catalysis conditions afforded 3-aryl-2,4-dibenzoyl-5-hydroxy-5-methylcyclohexanones. The reaction of benzoylacetone with benzalacetone led to the formation of 2-benzoyl-5-hydroxy-5-methyl-3-phenylcyclohexanone.

Synthesis of pyrimidinethiones and spiropyrans proceeding from Mannich ketones

New synthetic opportunities of conjugated and saturated β-aminoketones were revealed consisting in heterocyclization reactions with the formation of spirochromenes and hydropyrimidinethiones. Alicyclic conjugated Mannich bases under conditions of basic catalysis suffer deamination followed by [4+2]-cycloaddition leading to the stereo- and regiodirected formation of difficultly available spirochromene derivatives. Three-component condensation of acyclic and alicyclic Mannich ketones with thiourea and aromatic aldehydes under aprotic acid catalysis afforded functionalized derivatives of pyrimidine-2-thione series. Optimum conditions were found for О,N-heterocyclization of β-aminocarbonyl substrates.

ChemInform Abstract: A New Example of Cyclization of (E)‐1,5‐Diarylpent‐2‐en‐4‐yn‐1‐ones to Functionalized Furan Derivatives.

The reaction of (E)-1,5-diarylpent-2-en-4-yn-1-ones with 2-mercaptobenzothiazole and 2-mercaptobenzimidazole occurs under the conditions of basic catalysis and leads to the formation of 2-{[(5-arylfuran-2-yl)phenylmethyl]sulfanyl}-1,3-benzazoles in 50–90% yields.

A new example of cyclization of (E)-1,5-diarylpent-2-en-4-yn-1-ones to functionalized furan derivatives

The reaction of (E)-1,5-diarylpent-2-en-4-yn-1-ones with 2-mercaptobenzothiazole and 2-mercaptobenzimidazole occurs under the conditions of basic catalysis and leads to the formation of 2-{[(5-arylfuran-2-yl)phenylmethyl]sulfanyl}-1,3-benzazoles in 50–90% yields.

Modification of the silica particles surface with perfluoroalkylmethyloxiranes

Silica particles have been prepared via the sol-gel process in the presence of perfluoropropyl- and perfluorobutylmethyloxiranes. Nanoparticles are formed in the presence of acidic catalyst. Under conditions of basic catalysis the attack of silanol group (formed in situ via hydrolysis of tetraethoxysilane) on the oxirane ring leads likely to the Si-O-C bond formation.

Synthesis and application of chalcones to the preparation of heterocyclic structures

Condensation of methyl N-(4-acetylphenyl)carbamate with aromatic aldehydes in basic and acid environment, and also with hetarylaldehydes in the presence of bases afforded chalcones with the carbamate function. Under the conditions of basic catalysis a nucleophilic substitution was observed of a methoxy group in the carbamate moiety of the chalcone for an ethoxy group. The reactions of the obtained chalcones with hydrazine hydrate, isonicotinic acid hydrazide, guanidine and hydroxylamine hydrochlorides, thiourea, and selenium dioxide furnished the corresponding derivatives of pyrazole, oxazole, pyrimidine, and selenadiazole.

Reaction of 5-aryl-3H-furan-2-ones and their 3-arylmethylidene derivatives with thiosemicarbazide

O The interest to 3Н-furan-2—ones and their arylmethylidene derivatives is due to the structural features. The presence of several electrophilic sites, the reciprocal position of groups makes these compounds valuable substrates for the synthesis of versatile heterocyclic systems [1]. The goal of this study was obtaining substituted triazole structures by the reactions of 5-aryl-3Нfuran-2-ones and their 3-arylmethylidene derivatives with thiosemicarbazide under the conditions of basic catalysis. Reactions of 5-aryl-3Н-furan-2-ones Ia, Ib with thiosemicarbazide were carried out in ethanol solution in the presence of a catalytic quantity of triethylamine.

Effect of the nature of an organic solvent on polymorphic transformations of poly(strontium siloxanes)

Effect of the nature of an organic solvent (acetone, methyl ethyl ketone, 2-propanol, 2-ethoxyethanol, dimethylformamide) on the composition, structure, and polymorphic transformations of poly(strontium siloxanes) formed in hydrolytic copolycondensation of tetraethoxysilane with strontium chloride under basic catalysis conditions.

Affinity membranes prepared from hydrophilic coatings on microporous polysulfone hollow fibers

Microporous polysulfone hollow fibers were modified by reacting terminal phenol groups with ethylene glycol diglycidyl ether (EGDGE) to produce terminal epoxy groups. These were used to covalently link hydroxyethyl cellulose (HEC) polymers to the membrane surface. Further epoxidation of the HEC and reaction with hexane-diamine produced amine-terminated leashes on the microporous fibers. Recombinant protein A was linked to the amine functions and the resulting affinity membranes were evaluated for IgG capacities. The EGDGE reactions were studied under both acidic and basic catalysis conditions. IgG capacities of the acid-catalyzed reaction products reached as high as 20 mg/ml bed volume. Comparisons of equilibrium and dynamic capacities show that dynamic capacities are somewhat lower than the equilibrium capacities.

The cyclization of vicinal 1-amino-2-acylvinylated derivatives of aromatic amines

A general method for the synthesis of substituted fused polycyclic compounds containing a 4-alkylamino or 4-dialkylaminopyridine cycle has been proposed. The method includes the addition of primary or secondary amines to vicinal (acylethynyl)arylamines followed by the cyclization of the adducts under acidic or basic catalysis conditions. Various aminonaphthoquinolinediones and aminoquinolines have been prepared in high yields by this method.

Synthesis of sulfide derivatives of the carane series by reactions of 3-carene oxides with functional mercaptans

The reaction of 3-carene oxides with functional mercaptans under the conditions of basic catalysis takes place regio- and stereoselectively and is a convenient method of obtaining polyfunctional derivatives of 3-carene and the products of their chemical transformations (hydroxyethylthiocaranols, carboxyalkylthiocarenols, carane thiolactones). Together with the products mentioned, a new type of bicyclic, terpenes — bis-hydroxycaranyl) sulfides — is formed in th3ese reactions.

Reaction of ?-arylacryloxiranes with phenyl azide. Synthesis and chemical transformations of ?-phenylamino-?-arylacrylyloxiranes

The reaction of Β-arylacrylyloxiranes with phenyl azide by refluxing in dioxane or toluene leads to Β-phenylamino-Β-aryl-acrylyloxiranes. Epoxypropionyl- and Β-hydroxypropionyltriazoles are also isolated when the reaction is carried out in the dark without heating. It is shown that Β-phenylamino-Β-arylacrylyloxiranes undergo cyclization to 3(2H)-furanones in an acidic medium, whereas they are converted to 2,3-dihydro-4-pyridones under basic-catalysis conditions.

Z,E-isomers of 10,10-dimethyl-9-benzylidene-9,10-dihydro-10-sila-2-azaanthracene and reactions of 10,10-dimethyl-9,10-dihydro-10-sila-2-azaanthracene under conditions of basic catalysis

The synthesis of 9-benzylidenesilaazaanthracenes has been achieved, and the configurations of their Z- and E-isomers have been established. The reactions of silaazaanthracene in the presence of aromatic aldehydes and bases have been studied; these result in dimerization, oxidation, cleavage of the Si-C bond, and desilylation of the heterocyclic system.

Hydration of 3-methyl-3-norcarene epoxides under acid and basic catalysis conditions

The hydration of the cis- and trans-epoxides of 3-methyl-3-norcarene under acid catalysis conditions is characterized by a retention of the bicyclo[4.1.0]heptane structure and cleavage of the tertiary C-O bond of the epoxide rings; a regiospecificity of the opening is not observed under alkaline conditions.

ChemInform Abstract: NEW ASPECTS OF THE CHEMISTRY OF 2,3‐DIHYDRO‐1H‐1,5‐BENZODIAZEPINE

Under basic catalysis conditions the reaction of 4- and 4'-substituted chalcones with o-phenylenediamine leads to 2,3-dihydro-2,4-diaryl-1H-1,5-benzodiazepines; β-amino adducts, the ability of which to undergo intramolecular condensation increases as the basicity of the catalyst is increased, are formed as intermediates. A different pathway for the process (the formation of an azomethine) is observed in the reaction with cinnamaldehyde. It is concluded that conformational factors play a primary role in the direction of the reaction.

New aspects of the chemistry of 2,3-dihydro-1H-1,5-benzodiazepine

Under basic catalysis conditions the reaction of 4- and 4'-substituted chalcones with o-phenylenediamine leads to 2,3-dihydro-2,4-diaryl-1H-1,5-benzodiazepines; β-amino adducts, the ability of which to undergo intramolecular condensation increases as the basicity of the catalyst is increased, are formed as intermediates. A different pathway for the process (the formation of an azomethine) is observed in the reaction with cinnamaldehyde. It is concluded that conformational factors play a primary role in the direction of the reaction.

Research in the chemistry of pyrazolidine XXIII. Study of the reaction of 3,5-dioxopyrazolidines with ?-nitrostyrene

Products of Michael condensation containing a 1-phenyl-2-nitroethyl residue in the 4 position of the heteroring are formed in high yields in the reaction of equimolar amounts of 4-methyl-,4-ethyl-, 4-isopropyl-, 4-butyl-, 4-isoamyl-, and 4-phenyl-1, 2-diphenyl-3,5-dioxopyrazolidines and 1,2-diphenyl-3,5-dioxopyrazolidine with β-nitrostyrene under basic catalysis conditions. 1,2-Diphenyl-3,5-dioxopyrazolidine adds two equivalents of β-nitrostyrene when a twofold excess of the latter is present.

141. Optical activity in relation to tautomeric change. Part VI. Comparison of the rates of racemisation and of bromination of a ketone. A further study under conditions of basic catalysis

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