P-toluenesulfonic Acid Monohydrate Research Articles

Syntheses of Four‐Membered Metallacyclic Complexes with Nitrosylruthenium and Their Ring‐Opening upon HCl Addition

Symmetrically disubstituted bis(3-hydroxyalkynyl) complex [TpRu{C[triple chemical bond]CCPh(2)(OH)}(2)(NO)] (1) (Tp = BH(pyrazol-1-yl)(3)) and unsymmetrically mixed (arylalkynyl)(3-hydroxyalkynyl) congener [TpRu(C[triple chemical bond]CC(6)H(4)Me){C[triple chemical bond]CCPh(2)(OH)}(NO)] (2) were newly prepared. Treatment of 1 or 2 with p-toluenesulfonic acid monohydrate was carried out to give unusual four-membered metallacyclic complexes [TpRu{C(=C=CPh(2))C(O)C(=CPh(2))}(NO)] (3) and [TpRu{C(=C=CPh(2))C(O)CH(C(6)H(4)Me)}(NO)] (5), respectively, as major products. Formation mechanism of 3 and 5 would involve insertion of the generated allenylidene group (Ru=C=C=CPh(2)) into the other Ru--C(alkynyl) bond, followed by hydration of the resulting alpha-alkynyl--allenyl fragment. With regards to the chemical reactivity of their four-membered metallacycles, treatment with aq. HCl in MeOH afforded the ring-opened one-HCl adducts, [TpRuCl{C(=C=CPh(2))C(O)CH=CPh(2)}(NO)] (7) and [TpRuCl{C(=C=CPh(2))C(O)CH(2)(C(6)H(4)Me)}(NO)] (8). On the other hand, the use of CH(2)Cl(2) and THF as the reaction solvent gave another type of one-HCl adducts [TpRu{CH(C(Cl)=CPh(2))C(O)C(==CPh(2))}(NO)] (9 a/9 b) and [TpRu{CH(C(Cl)=CPh(2))C(O)CH(C(6)H(4)Me)}(NO)] (11 a/11 b) as diastereomeric pairs, still retaining the four-membered ring structure. Moreover, their kinetically controlled products 9 b and 11 b were treated with aq. HCl to afford the ring-opened two-HCl adducts [TpRuCl{C(C(Cl)=CPh(2))(H)C(O)CH=CPh(2)}(NO)] (10) and [TpRuCl{CH(C(6)H(4)Me)C(O)CH(2)(C(Cl)=CPh(2))}(NO)] (12), respectively. In 10 and 12, each one Ru--C bond is cleaved at mutually different positions in the ring. Protonation on the carbonyl group would trigger the formation of 7-12.

Trisannulated Benzene Derivatives by Acid Catalyzed Aldol Cyclotrimerizations of Cyclic Ketones. Methodology Development and Mechanistic Insight

Several factors that contribute to the success of aldol cyclotrimerizations have been clarified as part of an effort to shed light on the inner workings of this century old reaction. The use of 4,7-di-tert-butylacenaphthenone (11) as a mechanistic probe molecule has led to intriguing discoveries about temperature, solvent, and solubility effects. Solvents that are both polarizable and somewhat polar, e.g., o-dichlorobenzene (ODCB), work best for the aromatic ketones examined. Certain Brønsted acids were found to work better than Lewis acids as catalysts for the archetypal aldol cyclotrimerization of indanone (2) in aprotic solvents, and a strong dependence on the pKa of the acid was observed. A standardized protocol, using p-toluenesulfonic acid monohydrate, is shown to work well in a number of test cases.

Brønsted Acid Catalyzed Propargylation of 1,3-Dicarbonyl Derivatives. Synthesis of Tetrasubstituted Furans

Simple Brønsted acids such as p-toluenesulfonic acid monohydrate (PTS) efficiently catalyze a direct substitution of the hydroxyl group in propargylic alcohols with 1,3-dicarbonyl compounds. Selective propargylation or allenylation is obtained depending on the nature of the alkynol. Reactions can be performed in air in undried solvents with water being the only side product of the process. By applying this reaction as the key step, a range of interesting polysubstituted furans can easily be synthesized in a one-pot procedure. [reaction: see text].

Syntheses, spectral property, and antimicrobial activities of 6‐α‐amino dibenzo [d,f][1,3,2]dioxaphosphepin 6‐oxides

AbstractDiethyl α‐aminophosphonates (4) were prepared in excellent yield from three‐component reaction of aldehydes (1), amines (2), and triethylphosphite (3) under solvent‐free conditions in the presence of ceric ammonium nitrate (CAN) and were reacted with 2,2′‐dihydroxybiphenyl (5) using p‐toluene sulfonic acid monohydrate (PTSA) as a catalyst to obtain 6‐α‐aminodibenzo[d f][1,3,2]dioxaphosphepin 6‐oxides (6) in good yield. It is a first report on the cyclizations of 4 with 5. An antimicrobial activity of numbers of 6 is evaluated. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:2–8, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20244

Solvent‐Free Reduction of Aldehydes and Ketones Using Solid Acid‐Activated Sodium Borohydride.

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, please click on HTML or PDF.

Solvent-free reduction of aldehydes and ketones using solid acid-activated sodium borohydride

A simple and convenient procedure for the reduction of aldehydes and ketones with sodium borohydride activated by solid acids such as boric acid, benzoic acid, and p-toluenesulfonic acid monohydrate under solvent-free conditions is described.

Direct and Indirect Reductive Amination of Aldehydes and Ketones with Solid Acid Activated Sodium Borohydride under Solvent‐Free Conditions.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Practical Enantioselective Synthesis of β-Substituted-β-amino Esters

[reaction: see text] A practical, large-scale synthesis of a beta-amino ester 1 was developed. A chiral imine derived from (S)-phenylglycinol and 3-trimethylsilylpropanal was coupled with the Reformatsky reagent 3 with high diastereoselectivity (de > 98%) to give (SS)-4a as the major isomer. The amino alcohol residue of the coupling product 4 was oxidatively cleaved with sodium periodate in the presence of methylamine. An unusual selective oxidative cleavage of the (SS)-isomer was observed and the imine 6 was obtained with ee > 99% while the (RS)-4b isomer was not cleaved. Reaction with p-toluenesulfonic acid monohydrate allowed for the hydrolysis of the imine and the isolation of the amine as its salt. The title compound 1 was then obtained by transesterification, desilylation, and hydrochloride salt formation in a one-pot process. The method was successfully applied toward the synthesis of a wide variety of beta-amino esters.

Direct and indirect reductive amination of aldehydes and ketones with solid acid-activated sodium borohydride under solvent-free conditions

A simple and convenient procedure for reductive amination of aldehydes and ketones using sodium borohydride activated by boric acid, p-toluenesulfonic acid monohydrate or benzoic acid as reducing agent under solvent-free conditions is described.

Influence of the nature of the surface of polypyrrole films upon their interaction with volatile organic compounds

Although conducting polymers have been increasingly used in sensing devices to assess the quality of food and beverages, at present the details of the interaction mechanism between volatile organic compounds (VOCs) and the polymeric films used are not completely understood. In this work we examine how the sensitivity of polypyrrole films doped with different counter-ions (metanesulfonic acid sodium salt, octanesulfonic acid sodium salt, lithium perchlorate, p-toluenesulfonic acid monohydrate and anthraquinone-2-sulfonic acid sodium salt) towards polar (methanol, ethanol, 2-propanol and ethyl acetate) and apolar (hexane, benzene and carbon tetrachloride) VOCs can be correlated both to the chemical nature of the compounds and to the properties of the thin films determined by contact-angle measurements. The intensity of the observed response is higher for the case of the polar compounds, but in fact all sensors have shown sensitivity towards the examined VOCs. By adopting a principal component analysis it was also possible to discriminate between the different apolar compounds tested and between the members of the homologous series of alcohols. We have found that a positive correlation exists between the intensity of the response and the values of the dielectric constant, acidity, basicity and dipole moment of the VOCs, and that the sensitiveness to the polar [apolar] compounds is well correlated to the value of the polar [dispersive] component of the free surface energy of the thin films. Our results confirm that in the design of specific chemical sensors it is important to take into account the surface characteristics of the polymeric films.

Facile Synthesis of 1‐Substituted 2‐Amino‐3‐cyanopyrroles: New Synthetic Precursors for 5,6‐Unsubstituted Pyrrolo[2,3‐d]pyrimidines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Substituted Se‐Phenyl Selenocarboxylates from Terminal Alkynes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Facile synthesis of 1-substituted 2-amino-3-cyanopyrroles: new synthetic precursors for 5,6-unsubstituted pyrrolo[2,3-d]pyrimidines.

1-Benzyl-3-cyanopyrrole-2-carbonyl azide (5) underwent a Curtius rearrangement followed by quenching with alcohols to form the corresponding carbamates (6a-c). The carbamates 6a,b were unblocked to give the desired 2-amino-1-benzyl-3-cyanopyrrole (1a). A more facile procedure was subsequently developed for the synthesis of 1-substituted 2-amino-3-cyanopyrroles. N-Substituted aminoacetaldehyde dimethyl acetals (7a-c) were condensed with malononitrile in the presence of p-toluenesulfonic acid monohydrate to afford the corresponding 1-substituted 2-amino-3-cyanopyrroles (1a-c).

Effect of Suplatast tosilate (IPD) on chloride currents in human blood eosinophils

Rationale Alterations in chloride ion channels have been implicated in the induction of changes in cell shape and volume. Since blood and tissue eosinophilia is a hallmark of bronchial asthma, in this study we examined the effect of Suplatast tosilate (IPD), an anti-allergic drug that has been reported to be effective in the treatment of patients with allergy and interstitial cystitis, on chloride channel activity in human blood eosinophils. Methods Eosinophils were isolated from blood collected from allergic and allergic asthmatic donors. Chloride ion currents were recorded using whole cell patch-clamp technique in freshly isolated eosinophils. Current-voltage relationship of whole cell currents in human blood eosinophils was calculated and recorded. Results IPD increased both inward and outward chloride currents in human blood eosinophils. IPD in 1 ng/ml did not have significant effect on chloride current. However, at 5 ng/ml IPD had a very remarkable effect. The basic salt, p-toluenesulfonic acid monohydrate in 5 ng/ml or 50 ng/ml did not increase or decrease the chloride current in human blood eosinophils. Conclusion IPD activates both outward and inward chloride currents in human blood eosinophils. This effect is not due to its salt. The potent anti-allergic and anti-asthmatic effects of IPD could be due to its effect on chloride channels.

Synthesis, characterization, and partial hydrolysis of polyisoprene‐co‐poly(tert‐butyl methacrylate) and electrorheological properties of its suspensions

The synthesis, characterization, partial hydrolysis, and salt formation of polyisoprene-co-poly(tert-butyl methacrylate) and the electrorheological properties of its suspensions were investigated. The copolymer was characterized by gel permeation chromatography, viscosity measurements, 1 H-NMR, Fourier transform infrared spectroscopy, particle size measurements, and elemental analysis. The poly(tert-butyl methacrylate) units of the copolymer were partially hydrolyzed by p-toluene sulfonic acid monohydrate and then converted into a lithium salt. The conductivity of this copolymeric salt was measured to be 1.4 × 10 -9 S cm -1 . Suspensions of the copolymeric salt were prepared in four insulating oils (silicone oil, mineral oil, trioctyl trimellitate, and dioctyl phatalate) in a series of concentrations (5-33%, m/m). The gravitational stabilities of these suspensions were determined at 20 and 80°C. The flow times of the suspensions were measured under no electric field (electric field strength = 0) and under an applied electric field (electric field strength ¬= 0), and the electrorheological activity was observed. Furthermore, the effects of the solid particle concentration, the shear rate, the electric field strength, a high temperature, and the addition of promoters on the electrorheological activities of the suspensions were investigated, and the excess shear stresses were determined.

New Synthesis and Biologically Active Molecular Design of Deazapteridine-Steroid Hybrid Compounds

This paper describes a facile and general synthesis of a new class of the hybrid compounds (4, 5 and 16), possessing 5-deazapteridine and steroid in the same ring system, by condensation of 6-(monosubstituted amino)uracils (9) or 6-(monosubstituted amino)-2-phenylpyrimidin-4(3H)-ones (14) with 2-hydroxy-methyleneandrostanolone (10) or 2-hydroxymethylenetestosterone (15) under heating in the presence of p-toluenesulfonic acid monohydrate and their potential unti-coccidiosis activities.

Novel Oxidative α‐Tosyloxylation of Alcohols with Iodosylbenzene and p‐Toluenesulfonic Acid and Its Synthetic Use for Direct Preparation of Heteroaromatics.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Lactones. Part 16: Lactonization of γ,δ-epoxy esters with p-toluenesulfonic acid monohydrate

The reaction of cyclic γ,δ-epoxy esters with p-toluenesulfonic acid monohydrate is described. The reaction carried out in benzene or methylene chloride gave tosyloxy lactones as product. The ethoxy or methoxy lactones were obtained when ethanol or methanol were used as solvent. A mechanism of this lactonization is proposed.

Novel oxidative alpha-tosyloxylation of alcohols with iodosylbenzene and p-toluenesulfonic acid and its synthetic use for direct preparation of heteroaromatics.

alpha-Tosyloxyketones and alpha-tosyloxyaldehydes were directly prepared from alcohols by treatment with iodosylbenzene and p-toluenesulfonic acid monohydrate in good yields. This method can be used for the direct preparation of thiazoles, imidazoles, and imidazo[1,2-a]pyridines from alcohols in good to moderate yields by the successive treatment with iodosylbenzene and p-toluenesulfonic acid monohydrate, followed by thioamides, benzamidine, and 2-aminopyridine, respectively.

A novel positive photosensitive polybenzoxazole based on a tetrahydropyranyl (THP) protected polyhydroxyamide

A new positive working, aqueous base developable photosensitive polybenzoxazole (PBO) precursor composition based on a partially tetrahydropyranyl (THP) protected PBO precursor and a Bisphenol A based 1,2-naphthoquinone diazide-4-sulfonate (DNQ-4) photosensitive compound has been developed. The polymer was prepared from a low temperature polymerization of 2 , 2'-bis-(3-amino-4-hydroxyphenyl) hexafluoropropane (BisAPAF) and isophthaloyl chloride (IC), followed by reacting with 3,4-Dihydro-2H-pyran in the presence of p-toluenesulfonic acid monohydrate as a catalyst. The photosensitive PBO precursor containing 20wt % DNQ-4 photosensitive compound showed a sensitivity of 221 mJ/cm2 and a contrast of 1.44 in a 3 μm film with a 0.6wt % tetramethylammonium hydroxide (TMAH) developer. A pattern with a resolution of 10 μm was obtained from this composition. The novel PBO precursor photosensitive composition showed a significant improvement in dark film loss after development, which can and could be used to make a thick film resist.