- Effect of ionic crosslinking on the drug release properties of chitosan diacetate matrices
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Chitosan diacetate (CDA) was prepared by alkylating the amino moieties of chitosan with mono-iodoacetic acid. Subsequently, CDA was cross-linked with Al3+, Zn2+, and Ca2+ ions to yield three ionotropically crosslinked polymeric matrices. These composite matrices were characterized employing infrared spectroscopy (IR) and differential scanning calorimetry (DSC). Subsequently, they were loaded with caffeine, as a model drug, and were assessed as sustained release carriers by evaluating their caffeine release profiles. Interestingly, only CDA-Zn2+ complex sustained the release of caffeine effectively in a zero-order manner. The drug release and thermal behavior of the tested matrices agree with the relative strength of the ionic or coordination character of the bonds. This, in turn, depends on the position of the complexing ions on the electrophilic softness/hardness scale.
- Aiedeh, Khaled M.,Taha, Mutasem O.,Al-Hiari, Yusuf,Bustanji, Yasser,Alkhatib, Hatim S.
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Read Online
- A Straightforward Homologation of Carbon Dioxide with Magnesium Carbenoids en Route to α-Halocarboxylic Acids
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The homologation of carbon dioxide with stable, (enantiopure) magnesium carbenoids constitutes a valuable method for preparing α-halo acid derivatives. The tactic features a high level of chemocontrol, thus enabling the synthesis of variously functionalized analogues. The flexibility to generate magnesium carbenoids through sulfoxide-, halogen- or proton- Mg exchange accounts for the wide scope of the reaction. (Figure presented.).
- Monticelli, Serena,Urban, Ernst,Langer, Thierry,Holzer, Wolfgang,Pace, Vittorio
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supporting information
p. 1001 - 1006
(2019/01/30)
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- METHODS OF TREATING PAIN
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The present invention is directed to methods and compositions for inducing, promoting or otherwise facilitating pain relief. More particularly the present invention discloses the combination of a nitric oxide donor and an opioid analgesic in the therapeutic management of vertebrate animals including humans, for the prevention or alleviation of pain, particularly moderate to severe pain. In particular, the nitric oxide donor is a slow-release nitric oxide donor or is formulated to provide a sustained release of a low dose of nitric oxide.
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Page/Page column 35
(2008/06/13)
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- Thermolysis of alkoxyaluminum and siloxyaluminum acylates
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Thermolysis of alkoxyaluminum acylates (RO)nAl(OCORt)3-n (n = 1, 2; R = i-Pr, s-Bu, t-Bu, Rt = Ph, CH2I; R = PhCH2, Rt = Me, Et, Ph; R = Me3Si, Et3Si, Rt = Me) was studied. The main direction of thermolysis of derivatives of primary and secondary alcohols and of unsubstituted carboxylic acids is ester and alcohol formation. Trialkylsiloxyaluminum acylates termolyze to give in the first stage no other products than trialkylacyloxysilanes. Thermolysis of iodoacylates (RO)2AlOCOCH2I (R = Pr, s-Bu) involves oxidation of the alkoxy group to carbonyl compounds with simultaneous formation of a ketene and hydrogen iodide. tert-Butoxyaluminum acylates regardless of the structure of substituent in the acyloxy group undergo symmetrization to aluminum tert-butylate.
- Stepovik,Kazakina,Martynova
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p. 1371 - 1377
(2007/10/03)
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- Synthesis and thermal decomposition of derivatives of acyloxytetraphenylantimony
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Acyloxy derivatives of tetraphenylantimony of the general formula Ph4SbOC(O)R (R = Alk or Ar) have been synthesized by the reaction of pentaphenylantimony with carboxylic acids. Thermolysis of the compounds obtained affords phenyl carboxylates and triphenylstibine in quantitative yields. One of these compounds (R = CH=CHPh) has been studied by X-ray structural analysis. In this compound, the Sb atom has a trigonal-bipyramidal coordination. The Sb-O(Ph)eq distances are in the range 2.103(4)-2.140(5) A; the Sb-C(Ph)ax bond length is 2.167(5) A. The fragment of the residue of cinnamic acid has a delocalized double bond in the carboxylate group.
- Sharutina,Sharutin,Senchurin,Fukin,Zakharov,Yanovsky,Struchkov
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p. 186 - 190
(2007/10/03)
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- Macrolide immunomodulators
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Novel macrolide compounds of the formula STR1 and pharmaceutically acceptable salts, esters, amides and prodrugs thereof, processes for the preparation of the compounds of the invention, intermediates useful in these processes, a pharmaceutical composition, and a method of treating immunomodulatory disorders are disclosed.
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- Macrocyclic amide and urea immunomodulators
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Immunomodulatory macrocyclic compounds having the formula: STR1 and pharmaceutically-acceptable salts, esters, amides and prodrugs thereof, as well as pharmaceutical compositions containing the same, which possess immunosuppressive, antimicrobial, antifungal, antiviral, antiinflammatory and antiproliferative activity, as well as the ability to reverse chemotherapeutic drug resistance.
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- Reactions of nucleophilic substitution involving solid organic halogen compounds under shear deformation at high pressure
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Under conditions of shear deformation and high pressures (SD + HP), reactions of nucleophilic substitution were studied: 1) the replacement of aliphatic halogen atom with alkaline metal halides (halo-substituted aliphatic carboxylic acids, 1-bromoadamantane); 2) the replacement of halogen atom in aromatic nucleus (halobenzoic acids, dihalobenzenes) with halogen of salt; 3) the replacement of aliphatic halogen with hydroxyl (hydrolysis in a solid phase); 4) the replacement of halogen with amino group under deformation of the samples of ammonium α-halocarboxylates to give the corresponding amino acids.It was found that the exchange of the halogen atoms bonded with aliphatic carbon is most intensive in the mixtures of alkaline metal iodides with bromo-substituted acetic acid and propionic acids: the exchange reaction in these mixtures is observed even during grinding in the mortar. Unlike the liquid phase, under conditions of SD + HP exchange of the halogen atom of the aromatic nucleus with alkaline metal halides, proceeds successfully, and the reactivity of halides increases in the series Na K Rb Cs.Under SD + HP, 1-Br-adamantane reacts with water to form 1-adamantanol.A high reactivity of the water adsorbed by the reagents is observed. - Key words: shear deformation, high pressure, halogen derivatives of carboxylic acids, dihalobenzenes, alkaline metal halides, ammonium salts of halogen derivatives of carboxylic acids, amino acids, halo-substituted adamantanes, adamantanol, nucleophilic substitution reaction, hydrolysis, ball mill.
- Zharov, A. A.,Chistotina, N. P.,Gaziev, R. G.,Yakovleva, I. I.
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p. 1050 - 1055
(2007/10/02)
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- A New Microwave Reactor for Batchwise Organic Synthesis
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A laboratory-scale microwave batch reactor (MBR) has been developed for organic synthesis or kinetic studies on the 20-100 mL scale, with upper operating limits of 260 deg C and 10 MPa (100 atm).The MBR complements a continuous microwave reactor which was the subject of a previous report from the author's laboratory.Microwave-assisted organic reactions were conducted safely and conveniently in the MBR, for lengthy periods when required, and in volatile organic solvents.The use of water as a solvent for organic reactions was also explored.Examples include oxidation, elimination, esterifications, hydrolysis of a tertiary amide, etherification, isomerization, Hofmann elimination, α-iodination of a carboxylic acid, Claisen rearrangement, aminoreductone formation, and Willgerodt reactions.Advantages of the new MBR include the capability for rapid heating and quenching of reaction mixtures, minimal temperature gradients within the sample, and elimination of wall effects.Safety aspects have been discussed.
- Raner, Kevin D.,Strauss, Christopher R.,Trainor, Robert W.,Thorn, John S.
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p. 2456 - 2460
(2007/10/02)
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- HETEROCYCLIC HYDRAZIDE DERIVATIVES OF MONOCYCLIC BETA-LACTAM ANTIBIOTICS
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Antibacterial activity has been found in compounds of the formula. Compounds having the formula and pharmaceutically acceptable salts thereof, wherein: A is a bond or alkylene; Q completes a 5- or 6-membered saturated or unsaturated(including aromatic) heterocyclic ring having one or two, hetero atoms in the ring selected from nitrogen sulfur or oxygen; X is attached to an available carbon atom in the heterocyclic ring and is hydrogen or oxo; Y is attached to an available carbon atom in the heterocyclic ring and is hydrogen, amino, hydroxyl, halogen, carboxamide, nitrile, or carboxyl, except that Y is not carboxyl when the bicyclic ring completed by Q is 2-quinolyl, 3-quinolyl, or quinoxalyl; and the remaining symbols are as defined in the specification
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- Method for preparing dodecahydro-3a,6,6,9a-tetramethylnaphtho[2,1-b]furan and novel haloethyl decalin derivatives
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The method is directed to the preparation of dodecahydro-3a,6,6,9a-tetramethyl-naphtho[2,1-b]furan from sclareol using an alkoxy-radical fragmentation reaction. A novel 9-haloethyl decalin derivative is an intermediate in this method.
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- Water soluble prodrugs of camptothecin
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Water-soluble derivatives of camptothecin have the formulae: STR1 wherein R' is selected from the group consisting of R=CO CH2 NH2.HCl R=CO CH2 NHCH3.HCl R=CO CH2 NHC2 H5.HCl R=CO CH2 N(C2 H5)2.HCl R=CO CH(NH2) CH2 CH2 CH2 CH2 CH2 NH2.2HCl R=CO CH(NH2) CH2 CH2 COOH. HCl R=CO CH2 CH2.COO- Na+ R=HPO3- Na+
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- A NEW SYNTHESIS OF α-IODO CARBOXYLIC ACID USING IODINE-COPPER SALT
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Direct α-iodination of some carboxylic acids, namely, acetic acid, propionic acid, butyric acid, and valeric acid, using iodine-copper salt, gave the corresponding α-iodo carboxylic acid in high yield.This new synthetic method afforded several advantage over classical α-iodo carboxylic acid procedures.
- Horiuchi, C. Akira,Satoh, J. Yasuo
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p. 1509 - 1510
(2007/10/02)
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- MERCURATION OF 2-ALKYL-1,3-DIOXOLAN-2-YLIUM SALTS: NEW METHOD FOR THE SYNTHESIS OF α-MERCURIO CARBOXYLIC ACIDS
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In the mercuration of 2-alkyl-1,3-dioxolan-2-ylium perchlorates with mercury acetate of trifluoroacetate high yileds of mono-, di-, and tri-α-mercurio derivatives of carboxylic acids wre obtained, depenging on the proportions of the reacting substrates.
- Boev, V. I.,Dombrovskii, A. V.
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p. 1927 - 1930
(2007/10/02)
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- α-Iodination of Some Aliphatic Acids. Substituent Effect and Optimum Conditions
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The chlorosulfonic acid promoted α-iodination of some aliphatic acids in 1,2-dichloroethane has been studied.In contrast to the bromination, the effect of substituents on the rate shows not only a polar effect but also a steric effect in view of Taft's equation: , where ρ? = -1.20 and δ = 1.55 at 80 deg C.The transition state is discussed, which involves the electrophilic addition of I2 to a ketene intermediate.Aliphatic acids with less steric hindrance at the α-position, except acetic acid, are α-iodinated in good yields (ca. 80-100percent).The optimumconditions for α-iodination of long-chain aliphatic acids with caprylic acid as a model substrate are described.
- Ogata, Yoshiro,Watanabe, Shinya
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p. 2831 - 2834
(2007/10/02)
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- Aromatic amides of heterocyclic compounds and therapeutic compositions containing same
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The invention relates to aromatic amides N-substituted by heterocyclic groups. More particularly, the invention relates to substituted benzoic acid amides of 1-arylalkylamino or aminoalkyl-N-heterocyclic rings and to pharmaceutical compositions thereof, which have the ability to antagonize the effects of dopamine or dopaminergic agents of endogenous or exogenous origin and which may be used for the treatment of nausea and vomiting resulting from gastrointestinal disorders, congestive heart failure, post operative conditions, etc., other gastrointestinal disorders such as dyspepsia, flatulence, bile regurgitations, hiatus hernia, peptic ulcer, reflux aerophagitis, gastritis, duodenitis, and cholethiasis, and a variety of conditions affecting the central nervous system such as acute and chronic psychoses, maniacal psychosis, schizophrenias, serious disturbances of behavior and non-melancholic depressive state and migraine.
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