Presence Of Tributylamine Research Articles

THE BASE PRESENCE AT THE ALKYLSULFOCHLORINATION OF β-AMINOPROPIOAMIDOXIMES IN CHLOROFORM AND WATER

We have studied the regioselectivity of alkylsulfochlorination of β-(4-phenylpiperazin-1-yl)- and β-(benzimidazol-1-yl)-propioamidoximes using AlkSO2Cl under two conditions: (i) in chloroform in the presence of tributylamine (Bu3N) as a base at room temperature (r.t.); (ii) in water and acetone (4:1) without Bu3N at r.t. The reaction under the conditions (i) leads to the return of the original amidoximes, the formation of 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium chloride and β-(benzimidazole-1-yl)propioamidoxime hydrochloride. When alkylsulfochlorination occurs under conditions (ii): β-(4-phenylpiperazin-1-yl)propioamidoxime reacts with iso-propylsulfonyl chloride and β-(benzimidazol-1-yl)propioamidoxime ‒ with methylsulfonyl chloride, 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium hydrochloride, iso-propylsulfonate and O-methylsulfonyl-β-(benzimidazol-1-yl)propioamidoxime hydrochloride were obtained in quantitative yields. Thus, under conditions (i) Bu3N binds alkylsulfochlorides into alkylsulfonyltributylammonium chlorides and the alkylsulfochlorination products of β-aminopropioamidoximes were not formed; under conditions (ii) alkylsulfochlorination products were isolated: 2-amino-8-phenyl-1,5,8-triazaspiro[4.5]dec-1-ene-5-ammonium iso- hydrochloride, propylsulfonate and O-methylsulfonyl-β-(benzimidazole-1-yl)propioamidoxime hydrochloride.

Convenient synthesis of thiolated 2,7-disubstituted tropones via double C-N bond cleavage of tropinone derivatives.

A range of 2,4-dialkylidenetropinone-derived quaternary ammonium salts smoothly reacted with thiols in the presence of tributylamine, delivering structurally diverse thiolated 2,7-disubstituted tropones in moderate to excellent yields with high site selectivity. The reaction employs readily available feedstocks and reagents, is free of transition metals, tolerates various functional groups, and can be easily scaled up.

An Efficient Synthesis of Deoxyrhapontigenin-3-O-β-D-glucuronide, a Brain-targeted Derivative of Dietary Resveratrol, and its Precursor 4'-O-Me-Resveratrol.

Bioactive dietary polyphenols have health benefits against a variety of disorders, but some benefits of polyphenols may be not directly related to them but rather to their metabolites. Recently, we have identified the brain-available phenol glucuronide metabolite deoxyrhapontigenin-3-O-β-d-glucuronide (5) in perfused rat brains following subacute treatment with the stilbene resveratrol (1). However, the role of such a metabolite in the neuroprotective activity of resveratrol (1) is not understood, in part due to the noncommercial availability of 5 for performing biological evaluation in animal models of Alzheimer’s disease or other neurological disorders. Here, we describe a concise chemical synthesis of deoxyrhapontigenin-3-O-β-d-glucuronide (5) and its precursor 4-O-Me-resveratrol (2), accomplished in four and six steps with 74 and 21% overall yields, respectively, starting from commercially available 3,5-dihydroxybenzaldehyde. Pivotal reactions employed in the synthesis include the palladium-catalyzed C–C coupling between 3,5-di-tert-butyldiphenylsilyloxystyrene and p-iodoanisole in the presence of tributylamine and the acid-catalyzed glucuronidation between the trichloroacetimidate-activated glucuronic acid and 4-O-Me-resveratrol.

Development of an Isolable Active Ester, Diethyl Thiophosphoryl [(Z)-(2-Aminothiazol-4-yl)-2-(Methoxyimino)acetate (DAMA) for the Synthesis of Cefotaxime

An isolable activated ester, diethyl thiophosphoryl [(Z)-(2-aminothiazol-4-yl)-2-(methoxyimino)acetate (9a, DAMA) was prepared in high purity, which was at least stable for 7 d at and 6 months at . Its reaction with 7-ACA (4) in the presence of tributylamine in i-PrOH provided cefotaxime (1) of high purity in good yield. Preparation of DAMA and its reaction with 7-ACA (4) to 1 was performed in one-pot manner, respectively with minimal unit operations of stirring and filtration.

Synthesis and characterization of poly(thioether ether sulfone imide)s derived from isomeric bis(chlorophthalimide)s and bis(4-mercaptophenyl) sulfone

Abstract A series of isomeric bis(chlorophthalimide)s (BCPIs) were conveniently prepared from 3-chlorophthalic anhydride, 4-chlorophthalic anhydride, and mixtures thereof. Polymerization of BCPIs with bis(4-mercaptophenyl) sulfone (BMPS) proceeded smoothly in the presence of tributylamine, from which a class of isomeric poly(thioether ether sulfone imide)s (PTESIs) with inherent viscosities of 0.45–0.82 dL/g were obtained. The solubility, thermal stability, and mechanical properties of these polymers were characterized. Compared to the PTESIs derived from single BCPIs, i.e., 3,3′-, 3,4′-, or 4,4′-BCPIs, the PTESIs derived from mixed BCPIs showed better solubility and higher storage modulus. These PTESIs also demonstrated good thermal stability, giving only 5% weight loss at temperature of 490 °C in nitrogen atmosphere. The glass transition temperatures (Tgs) of these isomeric PTESIs were between 242 and 265 °C, and were increased with increasing of the ratio of 3-chlorophthalimide unit in the polymer backbone.

Electrochemiluminescence of lucigenin/tributylamine system in ethanol solution

The electrogenerated chemiluminescence (ECL) behavior of lucigenin in the presence of tributylamine (TBA) or other amines in ethanol solution at a polycrystalline gold electrode was studied under conventional cyclic voltammetric conditions. An anodic ECL peak (ECL-1 at 0.91 V vs. SCE) with two shoulders (S 1 at 0.52 V and S 2 at 1.19 V) and their counter-peaks (ECL-2 at 0.66 V, S 3 at 0.33 V, and S 4 at 1.07 V) during reversal potential scan were found in the lucigenin/TBA system. The effects of various factors such as media, material of electrode, concentration of lucigenin and TBA, atmosphere, electrolytes, and potential scan rate on ECL peaks were examined. The emitter of all ECL peaks was identified as N-methylacridone (NMA) by analyzing the ECL spectra. The mechanism for these ECL peaks is proposed to be due to the reactions of lucigenin with the free radical reductant such as Bu 3N and Bu 2NH electrogenerated by TBA at different potentials.

Hydrazine‐based polyimides from isomeric bis(chlorophthalimide)s

Abstract3,3′‐Dichloro‐N,N′‐biphthalimide (3,3′‐DCBPI), 3,4′‐dichloro‐N,N′‐biphthalimide (3,4′‐DCBPI), and 4,4′‐dichloro‐N,N′‐biphthalimide (4,4′‐DCBPI) were synthesized from 3‐ or 4‐chlorophthalic anhydrides and hydrazine in glacial acetic acid. The yield of 3,3′‐DCBPI (90%) was much higher than that of 4,4′‐DCBPI (33%) because of the better stability of the intermediate, 3‐chloro‐N‐aminophthalimide, and 3,3′‐DCBPI. A series of hydrazine‐based polyimides were prepared from isomeric DCBPIs and 4,4′‐thiobisbenzenethiol (TBBT) in N,N‐dimethylacetamide in the presence of tributylamine. Inherent viscosity of these polymers was in the range of 0.51–0.69 dL/g in 1‐methyl‐2‐pyrrolidinone (NMP) at 30 °C. These polyimides were soluble in 1,1,2,2‐terachloroethane, NMP, and phenols. The 5% weight‐loss temperatures (T5%s) of the polymers were near 450 °C in N2. Their glass‐transition temperatures (Tgs) determined by dynamic mechanical thermal analysis and differential scanning calorimetry increased according to the order of polyimides based on 4,4′‐DCBPI, 3,4′‐DCBPI, and 3,3′‐DCBPI. The hydrolytic stability of these polymers was measured under acid, basic, and neutral conditions and the results indicated that the order was 3,3′‐DCBPI/TBBT > 3,4′‐DCBPI/TBBT > 4,4′‐DCBPI/TBBT. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4933–4940, 2007

Selective Synthesis of Phosphate Monoesters by Dehydrative Condensation of Phosphoric Acid and Alcohols Promoted by Nucleophilic Bases.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Selective Synthesis of Phosphate Monoesters by Dehydrative Condensation of Phosphoric Acid and Alcohols Promoted by Nucleophilic Bases

Phosphate monoesters are synthesized from a mixture of phosphoric acid (1 or 2 equiv) and alcohols (1 equiv) in the presence of tributylamine. The reaction is promoted by nucleophilic bases such as N-alkylimidazole and 4-(N,N-dialkylamino)pyridine. 2',3'-O-Isopropylidene ribonucleosides are selectively converted to their 5'-monophosphates without the protection of amino groups in nucleobases.

Synthesis of new polyimidosulfides by Michael addition of bis(1-mercapto-2-ethylether) and amido thiosulfide oligomers

New polyimidosulfides were synthesized by Michael addition reaction of bis(1-mercapto-2-ethylether) and amido thiosulfide oligomers with various biscitraconimides. The reaction was performed at 120–130°C in N-methylpyrolidin-2-one and in the presence of tributylamine as a catalyst. The biscitraconimides were prepared by reaction of citraconanhydrides and diamines in glacial acetic acid at reflux. The structures of the resulting polymers were confirmed by elemental analysis, IR and 1H-NMR spectroscopy. They were characterized by viscometry, solubility, measurements of differential scanning calorimetry and thermal analysis.

Formation of silicon triazacorrole and tetrabenzotriazacorrole by the ring contraction of the corresponding tetraazaporphyrin ligands

Silicon-inserted triazacorrole, its μ-oxo dimer, and tetrabenzotriazacorrole have been obtained by ring contraction when metal-free tetraazaporphyrin (TAP) and phthalocyanine (Pc), respectively, were reacted with trichlorohydrosilane (HSiCl 3) in the presence of tributylamine in refluxing benzene. The triazacorrole has very sharp absorption at ca. 400 nm, which is suitable for blue-laser applications.

Synthesis and Characterization of Some New Polyimidothioethers with Ester Groups in the Backbone

New polythioethers were synthesized by Michael addition reaction of bis(1-mercapto-2-ethylether) with various bismaleimides containing ester groups in the backbone. The reaction was performed at room temperature using m-cresol as solvent and in the presence of tributylamine as catalyst. The structures of the obtained polymers were confirmed by IR, 1H-NMR spectroscopy, and elemental analysis. The polymers were characterized by determining softening points, evaluating their solubility and studying their thermal behavior by thermogravimetry (TGA), differential scanning calorimetry (DSC), and thermooptical (TOA) measurements.

Effect of diluents on the decomposition behavior of vinyl ester resin

An acidic vinyl ester resin (∼6 mg KOH per gram of solid) was prepared by reacting a bisphenol-A-based epoxy resin with acrylic acid in the presence of tributylamine. The acrylated epoxy resin thus obtained was characterized by Fourier transform infrared spectroscopy. Five samples of vinyl ester resin containing styrene and methyl methacrylate (MMA) in the weight ratios 40:0, 30:10, 20:20, 10:30, and 0:40 were prepared at 30°C. These samples were cured, using 2 phr benzoyl peroxide, at 90 ± 2 °C for 1 h. The decomposition behavior of all the samples was studied by thermogravimetric analysis (TGA) at 10°C min−1. The TG and dynamic thermogravimetry (DTG) thermograms showed single-step degradation in the individual cases of styrene and MMA, whereas a two-step degradation process was observed when styrene was mixed with MMA in any proportion. For all the samples, the order of the reaction was one for the first step. This value was calculated with the Coats and Redfern equation in accordance with the best-fit analysis and further confirmed by linear regression analysis. From this value of reaction order (n), the activation energy (E) and pre-exponential factor (Z) were calculated, and the validity of the data was checked by statistical analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1952–1956, 2003

Effect of diluents on the curing behavior of vinyl ester resin

AbstractAn acidic vinyl ester resin (∼6 mg KOH per gram of solid) was prepared by reacting a bisphenol‐A‐based epoxy resin with acrylic acid in the presence of tributyl amine. The acrylated epoxy resin thus obtained was characterized by Fourier transform infrared spectroscopy. Five samples of vinyl ester resin containing styrene and methyl methacrylate (MMA) in the weight ratios 40:0, 30:10, 20:20, 10:30, and 0:40 were prepared at 30°C, and their curing behavior was studied by differential scanning calorimetry in the presence of benzoyl peroxide (2 phr). Curing behavior was dependent on the ratio of the two monomers used as reactive diluents. The kinetic parameters were determined by Ozawa's method. The energy of activation and frequency factor varied from 17 to 23 kcal mol−1 and 8.47 × 109 to 5.21 × 1012 min−1, respectively and were lowest for the samples containing 30:10 and 10:30 styrene/MMA weight ratios. The curing reactions followed first‐order kinetics and obeyed the Arrhenius rate expression. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1948–1951, 2003

Synthesis of β-Keto Esters by Carbonylation of Halomethylketones

A number of β-keto esters were synthesized by Pd-catalyzed carbonylation of halomethylketones in the presence of tributylamine in 68-86% yields. The reaction is completed in 2 hours at 110 °C and 10 bar CO pressure. Chloromethylketones are carbonylated selectively while 2-bromoacetophenone is partly reduced to acetophenone as a byproduct. The reaction can be carried out at atmospheric pressure though the rate stays low. The reaction mechanism is discussed.

Anchoring of Pd on silica functionalized with nitrogen containing chelating groups and applications in catalysis

Pd-complexes of silica-anchored nitrogen containing chelating compounds were prepared by the following reactions: (a) synthesis of the Schiff-bases from 3-aminopropyltriethoxysilane and 2-acetylpyridine, 2-acetylpyrazine or 2,6-diacetylpyridine; (b) reduction of the Schiff-bases with NaBH 4 in methanol; (c) cogelification with tetraethyl orthosilicate (TEOS); (d) reaction of the obtained functionalized silica with [PdCl 2(PhCN) 2] in CH 2Cl 2. The corresponding model ligands and palladium complexes were also prepared from the reaction of n-propylamine with the pyridine or pyrazine compound, followed by the reduction with NaBH 4 and the reaction with [PdCl 2(PhCN) 2]. The products were characterized by BET, FTIR, GC–MS, 1 H- NMR and elemental C–H–N analysis. The anchored Pd-complexes were tested as catalysts in: (a) the Heck reaction of iodobenzene with ethyl acrylate or styrene in the presence of tributylamine, as base, and toluene or p-xylene, as solvent; (b) the carbonylation reaction of iodobenzene with CO, at atmospheric pressure, in methanol in the presence of triethylamine or potassium acetate, as base. The catalysts were separated from the reaction mixtures and re-used many times. The best results were obtained in both reactions with the anchored Pd-complexes prepared from 2-acetylpyridine: 14 cycles in the Heck reaction ( TON≃4100 mmol product/mmol Pd) and 20 cycles in the carbonylation of iodobenzene ( TON≃2300 mmol product/mmol Pd).

Syntheses and thermal properties of 5,10-disubstituted-2,3,7,8-tetracyano-5,10-dihydrodipyrazino[2,3-b:2′,3′-e]pyrazines and polymeric porphyrazines derived from 2,3-dichloro-5,6-dicyanopyrazine

Intermolecular cyclization of 2-alkylamino-3-chloro-5,6-dicyanopyrazine2 in the presence of tributylamine in N,N-dimethylformamide (DMF) gave 5,10-disubstituted-2,3,7,8-tetracyano-5,10-dihydrodipyrazino[2,3-b:2′,3′-e]pyrazines3, which showed strong mesomorphic property and were anticipated as new chromophoric system for functional dye materials. Absorption spectra, fluorescent properties and other physical properties were correlated with their chemical structures. Vanadyl oligomeric porphyrazine with long alkyl groups synthesized from3 had satisfactory solubility in tetrahydrofuran (THF), diethyl ether and dimethylsulfoxide (DMSO). The syntheses and characterization of vanadyl polymeric porphyrazines derived from3 with long alkyl groups are reported.

Synthesis of condensation polymers catalyzed by palladium-graphite

Palladium-graphite (PdGr) was applied to polycondensations as a heterogeneous palladium catalyst. Catalytic activities of PdGr for the Heck reaction and a carbonyl insertion reaction were investigated using the model reactions. Polycinnamamide was synthesized through the Heck reaction of N, N′-(3,4′-oxydiphenylene)bis(acrylamide) and bis(4-iodophenyl) ether catalyzed by PdGr. The polymerization proceeded efficiently in the presence of tributylamine, but required a long reaction time compared with the case of homogeneous catalysts. The resulting polymer was almost white in color, which means that it was less contaminated by palladium metal. The removal and recycling of PdGr were much easier than the case of homogeneous catalysts. Aramid was also synthesized through the carbonyl insertion reaction of m-diiodobenzene and bis(4-aminophenyl) ether catalyzed by PdGr. The rate of carbon monoxide consumption for the polymerization catalyzed by PdGr was almost equal to that catalyzed by the homogeneous palladium catalyst. In both cases, the structures of the resulting polymers were identical to those prepared by homogeneous palladium catalysts.

Preparation of Polycinnamamide Catalyzed by Palladium-Graphite through the Heck Reaction

Palladium-graphite (Pd-Gr) was successfully used as a heterogeneous catalyst for the preparation of polycinnamamide through the Heck reaction. The condensation reaction of ethyl acrylate and iodobenzene catalyzed by Pd-Gr proceeded efficiently in the presence of tributylamine in an aprotic polar solvent such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO). The polymerization of N,N'-(3,4'-oxydiphenylene)bis-(acrylamide) and bis(4-iodophenyl) ether catalyzed by Pd-Gr was carried out in the presence of tributylamine in DMF at 100 °C. The polymerization proceeded efficiently to form polycinnamamide, but required a longer reaction time compared to the polycondensation catalyzed by palladium acetate. The structure of the resulting polymer was confirmed as trans-polycinnamamide by two-dimensional NMR measurements. The resulting polymer was almost white, which means that it was less contaminated by palladium metal. The removal and recycling of Pd-Gr were much easier than in the case of homogeneous catalysts.

Synthesis of photodegradable polymers by SH-En polyaddition

The polyaddition reaction of the Michael donor 1.2-bis(2-mercaptoethoxy)ethane (Bis-SH) 2 as dithiol to various Michael acceptors such as divinyl sulfone (DVS) 1, N,N′-bismaleimido-4,4′-diphenylmethane 3, 4,4′-(N-maleimido)diphenyliodoniumchloride 4 and diallyl succinate 5 in the presence of tributylamine is described. Polymers were characterized by NMR-spectroscopy, elemental analysis, DSC and TG-analysis. In particular we synthesized a photosensitive polymer with 4,4′-(N-maleimido)diphenyliodonium chloride as comonomer, which eliminated analytical amounts of HCl during irradiation.