Monoammonium Salt Research Articles

Synthesis and Characterization of New 1,2-Disubstituted Ferrocenyl Bismuthines

Bismuthine Ph2BiFc containing the pendant arm 2-(Me2NCH2)- (1) on ferrocenyl ring was synthesized, and reaction of (1) with CH3I was carried out to obtain the monoammonium salt {[2-(Me3N+CH2)Fc]}BiPh2[I]- (2). Molecular structures of bismuthines (1) and (2) have been determined by X-ray crystallography. Compound (1) does not show hypervalent Bi-N interaction. New 1,2-disubstituted ferrocenyl bismuthines have been characterized by various physicochemical techniques.

Supramolecular Organization of Neutral and Ionic Forms of Pharmaceutically Relevant Glycyrrhizic Acid—Amphiphile Self-Assembly and Inclusion of Small Drug Molecules

The first structural characterization of glycyrrhizic acid, its monoammonium salt (AGA), and the complex of the salt with p-aminobenzoic acid in the solid state is reported. X-ray crystallography reveals that neutral and ionic forms of GA have similar supramolecular organization, with aglycon groups protruding from the 2D hydrogen-bonded sugar platform. Interpenetration of these assemblies leads to the generation of intersecting channels where solvent and guest molecules are enclosed. It is worth noting that small solvent molecules or cations can functionally replace three water molecules which are an integral part of the sugar platform in GA. The crystal structures indicate the drug and cation binding sites and explain the similar properties of glycyrrhizic acid and its salts. The presented structures provide information about the supramolecular organization of amphiphilic GA molecule in the solid state, giving a guide into a possible aggregation mode in gels and solutions.

An efficient synthesis of quinoxalines catalyzed by monoammonium salt of 12-tungstophosphoric acid

Monoammonium salt of 12-tungstophosphoric acid [(NH 4 )H 2 PW 12 O 40 ] catalyst was used for the synthesis of biologically important quinoxaline derivatives in excellent yields from various aromatic 1,2-dicarbonyl and 1,2-diamines. The methodology has the advantages of mild reaction conditions with simple workup procedure, even for the synthesis of quinoxaline derivatives from sterically hindered diamine.

Shape-controlled fabrication of polypyrrole microstructures by replicating organic crystals through electrostatic interactions

Polypyrrole (PPy) microstructures with diverse shapes were synthesized in an aqueous inorganic salt medium including organic crystals and pyrrole (Py). A series of sulfobenzoic acid salt forms with various cations (K+, Na+, Li+, NH4+) in different positions (para, meta, ortho) of the sulfonate group on the benzene ring were used to form organic crystals as sacrificial templates. Using these crystals, we produced five different shapes of PPy microstructures (hexagonal microplates, curled nanofibers, lozenge-shaped microplates, rigid rods, parallelogram microplates), which replicated the shapes of the organic crystal templates through electrostatic interaction between the anionic crystal surfaces and the cationic PPy chains. In contrast, PPy that was polymerized without crystals showed bulky agglomerates of 200–500 nm size. The electrical properties were dictated by the molecular structures of the organic salt molecules used. While the highest conductivity (200.3 Scm−1) was observed in PPy using crystals of para-linked 4-sulfobenzoic acid monopotassium salt, the lowest conductivity (0.8 Scm−1) was observed in PPy prepared in the presence of crystals of ortho-linked 2-sulfobenzoic acid monoammonium salt.

Preparation of aminofunctionalized TiO 2 surfaces by binding of organophosphates

Titanium dioxide (TiO 2) powder was chemically modified with 2-aminoethyl dihydrogen phosphate (AEPH 2) and with 2-aminoethyl hydrogen ammonium phosphate (AEPHNH 4) in order to achieve an aminofunctionalized high-surface-area TiO 2 carrier suitable for more complex functionalizing. AEPH 2 was found to form the monoammonium salt AEPHNH 4 with ammonium ion rather than the diammonium salt AEP(NH 4) 2. The AEPHNH 4 was thoroughly characterized by various techniques and compared with AEPH 2. Bonding of AEPH 2 and AEPHNH 4 with TiO 2 powder was studied. According to the 31P NMR and elemental analysis results, AEPH 2 and AEPHNH 4 form covalent chelate bidentate bonds between the phosphate group and the TiO 2, while the amino groups remain accessible, creating uniform aminofunctionalized TiO 2 surface fully occupied by AEP groups. Amount of AEP groups on TiO 2 was limited to 1.5 wt-%.

Macromol. Rapid Commun. 17/2009

Frontispiece: An alcohol-soluble ionic molecular glass based on a dendronized monoammonium salt is facilely synthesized and utilized as an interfacial electron-injection layer in a polymer light-emitting diode. Photovoltaic measurements under white light irradiation reveal that a thin layer of the new compound can significantly increase the built-in potential and thus facilitate electron injection from an Al cathode. Further details can be found in the article by G. Liu, A.-Y. Li, D. An, H. Wu, X.-H. Zhu,* Y. Li, X.-R. Miao, W.-L. Deng, W. Yang, Y. Cao, and J. Roncali on page 1484.

An Ionic Molecular Glass as Electron Injection Layer for Efficient Polymer Light‐Emitting Diode

An ionic molecular glass based on a dendronized monoammonium salt has been facilely synthesized and utilized as an interfacial electron-injection layer in a light-emitting diode (LED). The characterization of a yellow-green LED that involves an Al cathode and a thin layer of the new compound spin cast from a methanol solution has shown device performances comparable to those obtained with a Ba/Al cathode. Photovoltaic measurements under white light irradiation reveal that a thin layer of the new compound can significantly increase the built-in potential and thus facilitate electron injection from an Al cathode. Furthermore, it is interesting to observe that the new ionic salt could undergo reorganization on the emissive conjugated polymer layer, which leads to the formation of nearly uniform nanoaggregates.

Reaction features of 2,3,4-trichloro-1-butene with phosphoric and nitrogen nucleophiles

Reaction of 2,3,4-trichloro-1-butene with phosphoric and nitrogen nucleophiles was carried out. In the reaction with allyldiphenylphosphine 1,4-bis-(allyldiphenylphosphoniochlorido)-1,3-butadiene was obtained, with tributylphosphine, allyldimethylamine and trimethylamine respective 1,4-bis-onium salts with 2-chloro-2-butenylene group. Reaction with trimethylamine proceeded with formation of monoammonium salt with 3,4-dichloro-2-butenyl group. It is noteworthy that 1,4-splitting of 1,4-bis-(trimethylammoniochlorido)-2-butene at the action of sodium methoxide occurs with involvement of the less labile hydrogen atom.

Simple and Efficient Method for the Synthesis of Benzimidazole Derivatives using Monoammonium Salt of 12‐Tungstophosphoric Acid

Benzimidazoles have been synthesized in very good yield from o‐phenylenediamine and aromatic aldehydes in the presence of monoammonium salt of 12‐tungstophosphoric acid [(NH4)H2PW12O40], an efficient heterogeneous catalyst. This catalyst has the advantages of simple workup procedure, water insolubility, and good activity with high yield for the synthesis of benzimidazole derivatives.

Efficient Method for the Synthesis of 1,5‐Benzodiazepine Derivatives Catalyzed by Monoammonium Salt of 12‐Tungstophosphoric Acid.

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.

Efficient Method for the Synthesis of 1,5‐Benzodiazepine Derivatives Catalyzed by Monoammonium Salt of 12‐Tungstophosphoric Acid

Monoammonium salt of 12‐tungstophosphoric acid [(NH4)H2PW12O40] was found to be a practical, inexpensive, reusable, and efficient heterogeneous catalyst for the preparation of 1,5‐benzodiazepine derivatives of o‐phenylenediamine and ketones. The heteropolyacid‐based catalyst has the advantages of simple workup procedure, water insolubility with good activity, and high‐yielding reaction for the synthesis of 1,5‐benzodiazepine derivatives. IICT Communication No. 060112.

Selective Esterification of Aliphatic Carboxylic Acids in the Presence of Aromatic Carboxylic Acids over Monoammonium Salt of 12‐Tungstophosphoric Acid.

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.

Selective Esterification of Aliphatic Carboxylic Acids in the Presence of Aromatic Carboxylic Acids Over Monoammonium Salt of 12‐Tungstophosphoric Acid

Monoammonium salt of 12‐tungstophosphoric acid [(NH4)H2PW12O40] was found to be a practical and useful heterogeneous catalyst for an efficient and selective esterification of aliphatic carboxylic acids with alcohols in the presence of aromatic carboxylic acids. The heteropoly acid–based heterogeneous catalyst has the advantages of a simple workup procedure, water insolubility, and good activity. IICT Communication No. 040417.

First ferrocenylstibines and their molecular structures

Stibines Ph 2SbFc containing the pendant arm [2-(Me 2NCHR)] [where R = H( 1) or Me( 2)] on ferrocenyl ring were synthesized, and reaction of ( 1) with CH 3I was carried out to obtain the monoammonium salt {[2-(Me 3N +CH 2)Fc]} SbPh 2[I] −. All new stibines have been characterized by various physicochemical techniques. The structures of all these 1,2-disubstituted ferrocenylstibines were determined by X-ray diffraction analyses. This is the first report on the stibines containing disubstituted ferrocenyl group and it is worth mentioning that even monosubstituted ferrocenylstibines are virtually unknown. Heterobimetallic stibine ( 1) does not show intramolecular Sb–N interactions while the stibine ( 2) is stabilized by intramolecular Sb–N interactions.

Permeation-enhancing effects of chitosan formulations on recombinant hirudin-2 by nasal delivery in vitro and in vivo

To investigate the enhancing effects of chitosan with or without enhancers on nasal recombinant hirudin-2 (rHV2) delivery in vitro and in vivo, and to evaluate the ciliotoxicity of these formulations. The permeation-enhancing effect of various chitosan formulations was estimated by using the permeation coefficient of fluorescein isothiocyanate recombinant hirudin-2 (FITC-rHV2) across the excited rabbit nasal epithelium in vitro. The effect was further evaluated by measuring the blood concentration level after nasal absorption of FITC-rHV2 in rats. The mucosal ciliotoxicity of different formulations was evaluated with an in situ toad palate model. Chitosan at a concentration of 0.5% with or without various enhancers significantly increased the permeability coefficient (P) and relative bioavailability (Fr) of FITC-rHV2 compared with the blank control. The addition of 1% sodium dodecylsulfate, 5% Brij35, 5% Tween 80, 1.5% menthol, 1% glycyrrhizic acid monoammonium salt (GAM) or 4% Azone into the 0.5% chitosan solution resulted in a further increase in absorption (P<0.05) compared with 0.5% chitosan alone. But co-administration of chitosan with 5% hydroxyl-propyl-beta-cyclodextrin (HP-beta-CD), 5% lecithin or 0.1% ethylenediamine tetraacetic acid (EDTA) was not more effective than using the 0.5% chitosan solution alone. Chitosan alone and with 5% HP-beta-CD, 0.1% EDTA, 1% GAM or 5% Tween 80 was relatively less ciliotoxic. Chitosan with or without some enhancers was able to effectively promote the nasal absorption of recombinant hirudin, while not resulting in severe mucosal ciliotoxicity. A chitosan formulation system would be a useful approach for the nasal delivery of recombinant hirudin.

Chemical modification of glycyrrhizic acid as a route to new bioactive compounds for medicine.

Glycyrrhizic Acid (GL) is the major bioactive triterpene glycoside of licorice root (Glycyrrhiza Radix) extracts possessing a wide range of pharmacological properties (anti-inflammatory, anti-ulcer, anti-allergic, anti-dote, anti-oxidant, anti-tumor, anti-viral etc.). Official sources of GL are Glycyrrhiza glabra L. and Gl. uralensis Fish. (Leguminosae). The content of GL in licorice root is 2-24% of the dry weight. GL is one of the leading natural compounds for clinical trials of chronic active viral hepatitis and HIV infections (preparation Stronger Neo-Minophagen C, SNMC), and its monoammonium salt (glycyram, tussilinar) is used as an anti-inflammatory and anti-allergic remedy. The synthetic transformations of GL on carboxyl and hydroxyl groups were carried out to produce new bioactive derivatives for medicine. GL esters were produced containing fragments of bioactive acids (4-nitrobenzoic, cinnamic, salycilic, acetylsalycilic, nicotinic, isonicotinic). Bioactive amides of GL were synthesized using chloroanhydride technique and N,N'-diciclohexylcarbodiimide (DCC) method. The synthesis of acylthioureids and semicarbazones was carried out via the reaction of triacylisothiocianate of penta-O-acetyl-GL with primary amines and hydrazines. The chain of transformations of trichloranhydride of penta-O-acetyl-GL was made with the introduction of diazoketone groups in the molecule. A new group of GL derivatives to be triterpene glycopeptides was prepared by the activated esters method (N-hydrohysuccinimide-DCC or N-hydroxybenzotriazol-DCC) using alkyl (methyl, ethyl, propyl, butyl, tert-butyl) or benzyl (4-nitrobenzyl) esters of amino acids. The glycyrrhizyl analogs of the known immunostimulator, N-acetyl-muramoyldipeptide (MDP), were synthesized using Reagent Woodward K. A series of ureids and carbamates of GL was synthesized containing 5-amino-5-desoxy-D-xylopyranose units. The synthesis of 4-nitro-4-desoxy-glycosides, modified analogs of GL, was carried out by the oxidative splitting of the carbohydrate part of GL with NaIO(4). Triterpene 2-desoxy-D-glycosides, analogs of GL, were prepared by the glycal method in the presence of iodine-containing promoters or sulfonic acid cation-exchange resin KU-2-8 (H+) and LiBr. New anti-inflammatory and anti-ulcer agents were found among GL derivatives such as esters, amides, ureids, carbamates, thioureids and glycopeptides. GL glycopeptides are of interest as immunomodulators. Some of the chemically modified GL derivatives (salts, amides, glycopeptides) were potent HIV-1 and HIV-2 inhibitors in vitro. Preparation niglizin (penta-O-nicotinate of GL) was studied clinically as an anti-inflammatory agent and is of interest for studies as hepatoprotector and HIV inhibitor.

Crystal and Molecular Structure of Monoammonium Salt of 5‐nitroaminotetrazole

X‐ray structural investigation of the monoammonium salt of 5‐nitroaminotetrazole was performed. The crystals are orthorhombic: a = 10.077(1)A, b = 17.009(1)A, c = 6.6472(6)A, V = 1139.33(17)A3, space group Pbca, Z =8, ρcalc = 1.715 g/cm3. Monodeprotonation of 5‐nitroaminotetrazole during formation of the salt occurs at the N(4) nitrogen atom of the heterocycle. The anion has an almost flat structure; the bond lengths suggest delocalization of π‐electron density in the molecule. The negative charge is distributed among three nitrogen atoms and two oxygen atoms of the anion. Changes in the geometrical parameters of 5‐nitroaminotetrazole on monodeprotonation are considered.

Preparation and rectal absorption of highly concentrated glycyrrhizin solution.

We developed a simple method for preparing a highly concentrated solution of glycyrrhizin monoammonium salt (GZ) at low viscosity with no surfactants nor organic solvents and investigated the absorption profile after rectal administration to rats. GZ (200 mg/ml) was dissolved in phosphate buffered solution, pH 7.0; over 350 mM concentration was maintained for the aqueous solution without gel-formation. When glycerin was used as a non-aqueous formulation, GZ did not form gel. Apparent permeability coefficients of GZ obtained from 350 mM phosphate buffered solution (pH 7.0) and glycerin solution through rat rectal mucosa estimated by in vitro parallel diffusion chamber technique were 0.686 x 10(-6) and 0.379 x 10(-6) cm/s, respectively. On the other hand, the area under plasma concentration-time curves of GZ in 400 mM phosphate buffer (pH 7.0) and glycerin formulations after rectal administration to the rat were significantly higher than that in polyethylene glycol 400/propylene glycol (55 : 5) formulation. Maximum plasma concentrations of these formulations were dependent on the apparent permeability coefficients of GZ. Increased absorption observed by phosphate buffered formulation accompanied no pronounced histological damage in mucosa. These results demonstrate that addition of a highly concentrated phosphate salts is effective not only for lowering the viscosity of a highly concentration of GZ solution, but also for improving the mucosal GZ absorption.

Magnitudes and Orientations of Interaction Tensors Determined from Rotational Resonance MAS NMR Lineshapes of a Four-13C-Spin System

Possibilities and limitations of iterative lineshape fitting approaches for the complete determination of magnitudes and orientations of NMR interaction tensors in a four-13C-spin system from MAS NMR experiments are investigated. The availability of fast and numerically accurate computational methods is an important prerequisite. The model compound chosen for this investigation is the monoammonium salt of maleic acid. Various selectively and fully 13C-labeled versions of this compound permit a stepwise reduction of the number of unknown parameters, necessary to fully describe the four-13C-spin system in the uniformly 13C-labeled maleate moiety. This stepwise procedure allows one to monitor reliability and accuracy of multiparameter fits of the four-13C-spin system itself, as well as to characterize limitations and requirements for such fitting procedures. Satisfactory 1H-decoupling performance is an essential experimental requirement; TPPM decoupling yields n = 1, 2 rotational resonance 13C MAS NMR lineshapes suitable for analysis by iterative lineshape fitting methods. It is demonstrated that assumptions about “typical” chemical shielding tensor orientations, even if not deviating much from the real orientations, lead to severe errors in internuclear distance determinations.

A Simple Spectrophotometric Determination of Nitrate in Water, Resin, and Soil Extracts

AbstractNitrate is one of the most important chemicals in agricultural and environmental management. Most methods for NO3 analysis, however, require expensive equipment or complicated procedures. The objective of this study was to develop a simple, rapid, accurate procedure for NO3 analysis that can be conducted in laboratories worldwide, without the need for specialized equipment. We based our studies on a colorimetric method that involves electrophilic aromatic substitution (nitration) between nitronium and salicylate. The simplified procedure was tested for NO3 analysis of water, soil, and resin extracts. Only 1 mL of sample containing 0 to 4 mg NO3‐N L‐1 is required, and a single solution (TRI solution made as a mixture of sodium salicylate [2‐hydroxybenzoic acid monosodium salt], NaCl, and ammonium sulfamate [sulfamic acid monoammonium salt]) is used for color development. The detection limit is 0.1 µg NO3‐N, with linearity up to 4 µg NO3‐N in a final volume of 11 mL. Evaporation of the sample may be done in several ways to remove water from reactants, as long as the temperature for activiation of nitration is attained. Resin extracts from 2 M HCl required neutralization with 2 M NaOH prior to analysis, and soil extracts from 1 M KCl provided more uniform results than from 2 M KCl. Results from all types of solution samples were highly significantly correlated with those by the automated Cd‐reduction method. This simplified sodium salicylate procedure (SSP) for NO3 analysis is simple, reproducible, and it requires only inexpensive equipment.