Phase Transfer Catalysis Conditions Research Articles

Synthesis and Biological Evaluation of Some Novel Sulfonylurea and Sulfonamide Derivatives under Phase Transfer Catalysis Conditions

Classes of novel sulfonylurea and sulfonamide derivatives 3-13 were synthesized via three different roots, using pharmacologically active functionalized pyrimidine or piperidine-2,6-dione derivatives and p-toluene sulfonyl chloride under phase transfer conditions (PTC). The structures of all the newly synthesized compounds were characterized by IR, 1H-NMR and 13C-NMR spectroscopy. The title compounds were screened for antibacterial activity against two-gram positive bacterial strains such as Staphylococcus aureus and Bacillus subtilis and two-gram negative bacterial strains such as Escherichia coli and Pseudomonas aeruginosa and also screened for antifungal activity against Fusarium oxysporum, Candida albicans and Aspergillus niger pathogens. Compounds 3b, 4b, 6b, 6d, 8b, 11b, 13b and 13e exhibited potent activity and remaining derivatives showed moderate to weak activity against bacteria and fungi

Diastereo- and enantioselective preparation of oxazolines via the base-catalysed aldol reaction of isocyanoacetates with aldehydes using cinchona alkaloids

A diastereo- and enantioselective base-catalysed aldol reaction of t-butyl isocyanoacetate with aldehydes under phase-transfer catalytic conditions yielded 19 4,5-disubstituted oxazolines, 16 of which are novel. Key to success was the use of a free 9-OH-containing cinchona alkaloid-based quaternary ammonium salt bearing bulky and electron-withdrawing aryl groups on the N-benzyl moiety. This process tolerates both aromatic and aliphatic aldehydes, affording the corresponding chiral oxazoline products in diastereoselectivities up to 20:1 and enantioselectivities up to 78% ee.

ChemInform Abstract: Insecticidal Evaluation and [4 + 2] Aza‐Diels—Alder Synthesis of 3,7‐Diaryl‐6,7‐dihydro‐5H‐6‐substituted Thiazolo[3,2‐a]pyrimidin‐5‐ones under Coupled Ultrasonic Irradiation and PTC.

AbstractThe title compounds are prepared by [4+2] cycloaddition reaction of thiazole Schiff′s bases and in situ generated monosubstituted ketenes under phase transfer catalysis (PTC) conditions coupled with ultrasonication.

Naphthalenes Oxidation by Aqueous Sodium Hypochlorite Catalyzed by Ruthenium Salts Under Phase-Transfer Catalytic Conditions

Highly effective and fast oxidation of naphthalene(s) to phthalic acid(s) under biphasic conditions using nominal catalyst loading (0.5 mol%) of ruthenium chloride, 2.5 mol% tetrabutyl ammonium bromide as phase transfer catalyst and inexpensive aqueous sodium hypochlorite (NaOCl) as reagent has developed. Recovery, regeneration and reuse of the catalytic system add its merit to green chemistry. A nominal loading (0.5 mol%) of ruthenium chloride as catalyst and inexpensive aqueous sodium hypochlorite (aq. NaOCl) as reagent are found to be highly effective reaction system for the partial oxidation of naphthalene(s) to phthalic acid(s) under phase transfer catalyst (PTC) conditions. Recovery, regeneration and reuse of the “ruthenium-PTC” catalytic system add its merit to green chemistry.

Kinetic study on the synthesis of 1,4-dithiane under ultrasound and multi-site phase-transfer catalyst in liquid-liquid PTC condition

In this work, the simple, efficient and convenient method to synthesis of 1,4-dithiane from 1,2-dibromoethane and sodium sulfide under heterogeneous liquid-liquid phase-transfer catalysis (LL-PTC) condition in the presence of ultrasound irradiation (40 kHz, 300W) and multi-site phase-transfer catalyst was reported. The multi-site phase-transfer catalyst namely 1,4-dibenzyl-1,4-diazoniabicyclo[2.2.2]octanium dibromide (MPTC) was successfully prepared and used as a superior catalyst for this synthesis. The combination of both ultrasound and multi-site phase-transfer catalyst are resulted in enhanced reaction rate and efficiency than the individual operations. The reaction was carried out under pseudo-first order condition. The kinetic aspects such as the effect of agitation speeds, ultrasound frequencies, different phase transfer catalysts, various organic solvent, volume of hexane, the amount of prepared MPTC, various temperature, the amount of water, the concentration of 1,2-dibromoethane, on the conversion of 1,2-dibromoethane and the apparent rate constant (K app ) were investigated in detail. The suitable mechanism has been proposed for reaction system.

Application of In Situ FTIR for the Preparation of 17-α-Estradiol via Mitsunobu Reaction

An efficient synthesis of 17-α-estradiol 1 is described. Utilization of in situ IR allowed for an online monitoring of the key Mitsunobu reaction and development of a safe and reliable synthesis of 17-α-estradiol 1 in 78% overall yield over three steps. Benzoylation of 17-β-estradiol 2 is conducted at high regioselectivity under phase-transfer catalysis (PTC) conditions, followed by a Mitsunobu reaction to invert the chiral center at C-17 and provide intermediate 5, containing the core structure of 17-α-estradiol 1. Finally, the desired active pharmaceutical ingredient (API) is prepared by saponification of the remaining esters.

ChemInform Abstract: Catalytic Enantioselective Addition of Isocyanoacetate to 3‐Methyl‐4‐nitro‐5‐styrylisoxazoles under Phase Transfer Catalysis Conditions.

AbstractThe reaction of styrylisoxazoles (I) with ethyl isocyanoacetate (II) in the presence of N‐benzylcinchonidinium bromides TFCB or DTBC leads to diastereomeric mixtures of isocyanates (III), which are readily cyclized with N‐ethyldiisopropylamine to afford chiral 2,3‐dihydropyrroles as a single diastereomer with good to high enantioselectivity.

Sustainable Oxidations under Phase-Transfer Catalysis Conditions

Phase-transfer catalysis (PTC) is a well-known useful tool to develop sustainable processes. Benefits deriving from using PTC are particularly evident in oxidation chemistry where it has been possible to replace many toxic, aggressive reagents with harmless and milder oxidants such as bleach or hydrogen peroxide.

Utility of CyanoaceticAcid Hydrazide in Organic Synthesis: Synthesis and Characterization of Some Novel Heterocycles bearing 1,3,4-Oxadiazole Moeity

2,2'-(1,3,4-oxadiazole-2,5-diyl)diacetonitrile 2 has been prepared expeditiously from 2-cyano-N’-(2-cyanoacetyl)acetohydrazide1. Reaction of 2,2'-(1,3,4-oxadiazole-2,5-diyl)diacetonitrile 2 with aromatic aldehydes under mild alkaline conditions afforded the corresponding condensation products 3a-d, which in turn allowed to react with hydrazine, phenylhydrazine or hydroxylamine to give pyrazole and iosxazole derivatives (4-6)a-d. Also compound 3a-d was reacted with acetylacetone or ethyl acetoacetate to give pyran derivatives (7,8)a-d. Condensation of compound 2 with cyclopentanone afforded compound 9 which was reacted with acetylacetone or ethyl acetoacetate to give the corresponding spiropyran derivatives 10 and 11 respectively. The one-pot reaction of compound 2 with carbon disulfide or phenylisocyanate and ethyl chloroacetate under phase transfer catalysis conditions afforded the corresponding thiophene derivatives 12 and 13 respectively. Finally, the reaction of compound 2 with ethylcyanoacetate was studied carefully under non-catalytic and catalytic conditions where compounds 14-16 were obtained respectively. The antimicrobial activity of the obtained compounds was examined. The obtained products were characterised by their elemental and spectral data.

Synthesis of Some New Fused and Spiro Heterocyclic Compounds under Phase Transfer Catalysis (PTC) Conditions

Synthesis of Some New Fused and Spiro Heterocyclic Compounds under Phase Transfer Catalysis (PTC) Conditions

Kinetic investigation on liquid–liquid–solid phase transfer catalyzed synthesis of dibenzyl disulfide with H2S-laden monoethanolamine

An investigation has been done on the utilization of H2S for the synthesis of dibenzyl disulfide (DBDS) using Amberlite IR-400 as a phase transfer catalyst. This involves absorption of H2S in aqueous monoethanolamine (MEA) followed by reaction of this H2S-laden MEA with organic reactant benzyl chloride (BC) to yield DBDS under liquid–liquid–solid (L–L–S) phase transfer catalysis condition. The effect of various parameters on the conversion of BC was studied and the selectivity of desired product was 100% at some level of process parameters. A suitable reaction mechanism has been proposed and a mathematical model has been developed to explain the kinetics of the reaction. Waste minimization was therefore affected with the utilization of H2S-laden gas for production of a value-added fine chemical.

Synthesis of Novel Fused Heterocycles Based on 6‐Amino‐4‐phenyl‐2‐thioxo‐1,2‐dihydropyridine‐3,5‐dicarbonitrile

Under phase transfer catalysis conditions, 6‐amino‐4‐phenyl‐2‐thioxo‐1,2‐dihydropyridine‐3,5‐dicarbonitrile (1) was allowed to react with halo compounds, acrylonitrile, chloroacetyl chloride, ethyl cyanoacetate, formamide, triethylorthoformate, or formic acid to give new derivatives of fused pyridines 2–22, respectively. Acetylation of compound 1 using acetic anhydride afforded product 23, which in turn underwent intramolecular cyclization in pyridine to give the corresponding pyrido[2,3‐d]pyrimidine 24.

Synthesis of novel coumarin derivatives based on 6-aminocoumarin, kinetic inspection of base hydrolysis, and spectrophotometric tracer of intermediate progress

The importance of 6-aminocoumarin, d-glucose, and ethyl cyanoacetate in pharmaceutical field was documented in literatures. Therefore, 6-aminocoumarin was reacted with single and double molarity of d-glucose forming Schiff’s base and bis-compound derivatives. Also, it was reacted with CS2 in phase transfer catalysis condition producing dithiocarbamate, which was used as an intermediate for the preparation of fused and polyfused derivatives. Additionally, it was reacted with dicarbonyl compounds via the condensation reaction to give the polycarbonyl derivatives. 6-Aminocoumarin was reacted with ethyl cyanoacetate via the addition and condensation reaction mechanisms; the effect of the side chains at the stability of some of these coumarins has been recorded. The kinetics of the base hydrolysis of 6-aminocoumarin and some of its derivatives was studied spectrophotometrically in aqueous medium at 298 K under pseudo-first-order conditions ([OH−] >> [Compound]). The suggested general rate equation can be given as: rate = {k 1 + k 2 [OH−]} [complex]. The reasonable mechanism suggested that the investigated reaction proceeded via the formation of an intermediate and the ring opening of the formed intermediate was the rate determining step. This is the first time in which the kinetics of the formation and decay of the intermediate were followed (at [OH−] ≤ 3.5 × 10−2 mol dm−3).

ChemInform Abstract: Solid‐Liquid Phase C‐Alkylation of Active Methylene Containing Compounds under Microwave Conditions

AbstractReview: 65 refs.

Acylation of humic acids

A method for the chemical modification of humic acids with benzoyl chloride under the conditions of phase-transfer catalysis was developed. It was demonstrated by potentiometric titration that the reaction of humic acids with benzoyl chloride can occur at both hydroxyl (–OH) and carboxyl (–COOH) groups. The antioxidant activity of the initial humic acids and their chemical modification products in radical-chain oxidation processes in an organic medium was determined by a gas-volumetric method. A decrease in the antioxidant activity of the acylated humic acids in comparison with that of the native forms was found; this can be related to a decrease in the amount of active functional groups (–OH,–NH, and–SH) due to binding with benzoyl chloride.

The novel synthetic route of 3,5-dimethyl-1-(3-phenylpropyl)-1H-pyrazole under solid–liquid phase transfer catalysis conditions assisted by an ultrasound application—A study of some kinetic parameters

The kinetic study for synthesis of 3,5-dimethyl-1-(3-phenylpropyl)-1H-pyrazole was studied successfully by reacting the 3,5-dimethyl pyrazole with 1-bromo-3-phenyl propane under phase transfer catalysis and ultrasonic irradiation conditions using aqueous solution of NaOH (5 g or 0.25 g/ml), excess amount of bromobenzene and tetrahexyl ammonium bromide as a phase transfer catalyst. The reaction was carried out at 40 °C under pseudo-first order conditions and was monitored by gas chromatography (GC). Kinetic reaction found to follow ‘pseudo first order’ rate law. From the experimental data, a rate expression had been developed to explain the kinetic behavior of the reaction from which the apparent rate constant (kapp) of the organic phase was attained. The effects of agitation speed, amount of sodium hydroxide, effect of quaternary ammonium salts, amount of catalyst and temperature on the reaction were also studied.

Synthesis and X-ray analysis of 2-aryl-4-chloropyrrolidine-2-carbonitrile derivatives

A procedure has been developed for the synthesis of ethyl 1-benzoyl-4-chloro-2-phenylpyrrolidine-2-carboxylate and 4-chloro-5-oxo-1,2-diphenyl-, 1-benzoyl-2-(2-benzyloxy-5-chlorophenyl)-4-chloro-, and 1-benzoyl-2-(4-benzyloxyphenyl)-4-chloropyrrolidine-2-carbonitriles in high yields via intramolecular cyclization of the corresponding 2,3-dichloropropionamides under conditions of phase-transfer catalysis.

Alkaline hydrolysis of dicyclohexyl adipate in the production of cyclohexanone for caprolactam synthesis

Kinetic characteristics have been determined and a mathematic model has been proposed for the alkaline hydrolysis reaction of dicyclohexyl adipate, a sterically hindered ester, under phase-transfer catalysis conditions; energy characteristics have been compared for the hydrolysis under heterogeneous (with and without a phase-transfer catalyst (PTC)) and homogeneous conditions. It has been demonstrated that a 90–95% conversion of the reactant can be achieved in the presence of 0.015–0.02 mol/L methyl trioctyl ammonium chloride (TOMAC, Aliquat-336) at 80–90°C over 90–120 min.

Solid-Liquid Phase C-Alkylation of Active Methylene Containing Compounds under Microwave Conditions

The solid–liquid phase C-alkylation of active methylene containing compounds with C=O or P=O functions under phase transfer catalysis or microwave conditions has been summarized in this minireview. The mono- and dialkylation of the methylene containing derivatives was investigated under microwave (MW) conditions. It was found that in many cases, there was no need to use phase transfer catalyst under MW conditions. Moreover, most of the reactions were carried out without any solvent. These results mean a serious green chemical advantage.

Cyclopropanation of 5-(1-Bromo-2-phenyl-vinyl)-3-methyl-4-nitro-isoxazoles under Phase Transfer Catalysis (PTC) Conditions

Heavily substituted cyclopropane esters were prepared in high yields, complete diastereoselection and average (up to 58%) enantioselectivity. The reaction described herein entailed reacting 4-nitro-5-bromostyrylisoxazoles, a class of powerful Michael acceptors with malonate esters under the catalysis of 5 mol% of a chincona derived phase-transfer catalyst.