Substituenteneinfluß auf die Bindung von Metallkationen an Amiden

The interactions of a series of cations with acetamide and its homologs is investigated using¹H-n.m.r. spectroscopy. The complexation of a cation by the amide induces changes in the electronic distribution of the ligands which lead to different chemical shifts in the n.m.r. spectra. The results are in agreement withab initio-calculations of the atomic population by the Mulliken Populations Analysis method using a minimal basis set.

     

An Easy One-Pot Procedure for the Synthesis of <Emphasis Type="Italic">N</Emphasis>-Sulfonyl Phosphorous Ylides and Sulfonyl Iminophosphoranes

Summary. Reaction of triphenylphosphine and an electron deficient acetylenic ester in the presence of strong N–H acid such as alkyl and aryl sulfamides or acetamide produces phosphorous ylides at room temperature in CH₂Cl₂. The aryl sulfamide phosphoranes undergo a smooth transformation reaction in boiling toluene and produce iminophosphoranes.     

Starch Derivatives of High Degree of Functionalization 11: Studies on Alternative Acylation of Starch with Long-chain Fatty Acids Homogeneously in <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-dimethyl acetamide/LiCl

Starch materials of different amylose content were allowed to react with saturated and unsaturated fatty acids of varying chain length from C₁₄ to C₁₈ under homogeneous conditions applying the solvent N,N-dimethyl acetamide in combination with LiCl. As reagent the corresponding acid chlorides and, alternatively, carboxylic acids in situ activated with toluene-4-sulfonyl chloride and N,N′-carbonyldiimidazole (CDI) were studied. Using fatty acid chlorides (FACl) and toluene-4-sulfonyl chloride-activated acids an almost complete substitution of the starch occurs. By in situ activation of the fatty acids with CDI, products with a degree of substitution up to 2 were obtained, which, in particular, represents a simple and very mild procedure.     

Bioactive metabolites of the marine actinobacterium <Emphasis Type="Italic">Streptomyces</Emphasis> sp. KMM 7210

New 3-(4-hydroxybenzyl)piperazine-2,5-dione, together with the known N-[2-(4-hydroxy-phenyl)ethyl]acetamide (N-acetyltyramine), was isolated for the first time from the marine actinobacterium Streptomyces sp. The chemical structures of these compounds were determined by NMR spectroscopy and mass spectrometry. The cytotoxic activities of the compounds were estimated from their effects on sperm and eggs of the sea urchin Strongylocentrotus intermedius. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 807–809, April, 2007.     

Acetamide/SO2Cl2 as an efficient reagent for Friedel–Craft’s acylation of aromatic compounds under ultrasonic and microwave conditions

Acetamide/SO₂Cl₂ reagent has been developed for effective Friedel–Craft’s acylation of aromatic compounds. Acylation of aromatic compounds with acetamide/SO₂Cl₂ was much more effective and faster than analogous (acetamide/SOCl₂) and (acetamide/POCl₃) reagents even under conventional conditions. However, microwave and ultrasonic assisted reactions afforded high yields of products in very short reaction times (30–40 min under sonication and 3–4 min under microwave assisted conditions).     

Zur Bildung von Xylol-tricarbonylchrom (Dimethylbenchrotrenen) aus Di-n-butylether und Hexacarbonylchrom

The reaction of fluorenone ethyleneketal (9), diphenic anhydride as well as of biphenyls such as4 with Cr(CO)₆ in refluxing di-n-butylether (BE) gives dimethylbenchrotrenes [xylene-Cr(CO)₃,7] which are also formed by refluxing pureBE with Cr(CO)₆—although with much lower yields. Similarily, from di-n-pentylether and Cr(CO)₆ isobutyl- and 1-methyl-3-propyl-benchrotrene (13 and14) were obtained, whilst from di-n-propyl- and-hexylether, resp., and Cr(CO)₆ no benchrotrenes could be isolated.Tentative assumptions on the catalytic action of certain functional groups were confirmed by the reaction ofBE and Cr(CO)₆ in the presence of carbonamides, such as acetamide, urea and pyrrolidone, where 1,4-dimethylbenchrotrene (7 c) was formed with appreciable yields.Studies using dideuteratedBE showed that—at least for the reaction of9 with Cr(CO)₆ (giving a much lower yield of7 than with undeuteratedBE)—a simple bimolecular mechanism can be excluded.

     

A Stability Indicating Proton NMR Spectroscopic Assay Method for Succinylcholine Chloride Injections

Abstract

A simple, accurate, and specific -¹H-NMR spectroscopic method is presented for the assay of succinylcholine chloride injections. After freeze-drying the sample solution, a mixture of the residue with acetamide, serving as the internal standard, is dissolved in deuterium oxide, and the spectrum of the solution is recorded. The quantity of drug in the dosage form is calculated from the integral values for the resonance signals at ca. 2.01 ppm (acetamide) and ca. 3.27 ppm (succinylcholine chloride). The mean ± SD recovery value from synthetic formulations was 99.93 ± 0.60% (n = 10), with a corresponding CV of 0.60%. Assay values for a group of 10 commercial samples ranged from 86.1 to 100.7 (mean = 98.01)% of declared. Injection additives such as methyl paraben and benzyl alcohol did not interfere with the assays. The proposed method will also permit the simultaneous monitoring of the hydrolytic degradation of succinylcholine to its ester components.     

Comparative study of amidase production by free and immobilized Escherichia coli cells

Escherichia coli NCIM 2569 was evaluated for its potential for amidase production under submerged fermentation. Among the various amide compounds screened, maximum substrate specificity and enzyme yield (8.1 U/mL) were obtained by using 1% acetamide. Fermentation was carried out at 30°C in shake-flask culture under optimized process conditions. A maximum of 0.52 U/mL of intracellular amidase activity was also obtained from cells incubated for 24 h. Studies were also performed to elucidate the optimal conditions (gel concentration, initial biomass, curing period of beads, and calcium ion concentration in the production medium) for immobilization of whole cells. By using E. coli cells entrapped in alginate, a maximum of 6.2 U/mL of enzyme activity was obtained after 12 h of incubation under optimized conditions. Using the immobilized cells, three repeated batches were carried out successfully, and 85% of the initial enzyme activity was retained in the second and third batches. The study indicated that the immobilized E. coli cells offered certain advantages such as less time for maximum enzyme production, more stability in the enzyme production rate, and repeated use of the biocatalyst.     

N-Chlorophthalimide as a mild and efficient chlorination reagent in the Gassman ortho alkylation of aromatic amines. Synthesis of 3-(methylthio)oxindoles

A practical modification of the Gassman 3-(methylthio)oxindole synthesis is reported. In our method, substituted anilines and 2-(methylthio)acetamide were reacted under mild reaction conditions, in the presence of N-chlorophthalimide as a chlorinating agent to give α-amidosulfides, which, in the next step of the process, were cyclized to give 3-(methylthio)oxindoles. The method was successfully applied for the synthesis of the key intermediate, 2-(2-amino-3-benzoylphenyl)-2-(methylthio)acetamide, in the process of the preparation of nepafenac, a commonly used ophthalmic drug.     

Tetrakis(acetonitrile)copper(I) Hexafluorophosphate–Promoted Efficient Synthesis of Amidoalkyl Naphthols Under Solvent-Free Conditions

An efficient and direct protocol for the preparation of amidoalkyl naphthols employing a multicomponent, one-pot condensation reaction of β-naphthol, aromatic aldehydes, and amides (acetamide, benzamide, and urea) in the presence of tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu(CH₃CN)₄PF₆] under solvent-free conditions at 80 °C is described. Good yields, short reaction time, and easy workup are advantages of this procedure.     

Synthesis and properties of pyrimido[4,5-<Emphasis Type="Italic">a</Emphasis>]- and pyrido[4,3-<Emphasis Type="Italic">a</Emphasis>]carbazole derivatives

Methods for the synthesis of substituted pyrimido [4,5-a]- and pyrido[4,3-a]carbazoles were proposed. Condensation of 2-(dimethylaminomethylene)-6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-one with guanidine and thiourea afforded 2-amino-8-methyl-6,11-dihydro-5H-pyrimido[4,5-a]carbazole and 8-methyl-3,5,6,11-tetrahydro-2H-pyrimido[4,5-a]carbazole-2-thione, respectively. The reaction of cyano(6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-ylidene)acetamide with dimethylformamide dimethyl acetal gave N-(dimethylamino-methylene)cyano(6-methyl-2,3,4,9-tetrahydro-1H-carbazol-1-ylidene)acetamide. Cyclization of the latter yielded 1-cyano-8-methyl-3,5,6,11-tetrahydro-2H-pyrido[4,3-a]carbazol-2-one.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2740–2744, December, 2004.     

Indium(III) Chloride: An Efficient Catalyst for the Synthesis of Amidoalkyl Naphthols

Indium chloride was found to be a very efficient catalyst for the synthesis of amidoalkyl naphthols from β-naphthol, aromatic aldehydes, and acetamide/urea under solvent-free conditions using microwave irradiation.     

Rapid Method of Converting Primary Amides to Nitriles and Nitriles to Primary Amides by ZnCl2 using Microwaves under Different Reaction Conditions

A rapid and facile method for the conversion of primary amides to nitriles using inexpensive and readily available ZnCl₂ in aqueous acetonitrile and their regeneration using ZnCl₂–H₂O–THF in the presence of acetamide under microwave irradiation in good yields is reported. The reactions go to completion within a minute.     

A study of the Claisen—Eschenmoser reaction for hydroxymethylbenzofurans and-indoles

N,N-Dimethylacetamide dimethyl acetal reacted with 5(7)-substituted 2-(hydroxy-methyl)benzofurans to give N,N-dimethyl-2-(2-methylbenzofuran-3-yl)acetamides. Analogous reactions with 3-(hydroxymethyl)indole and 1-hydroxy-6-methyl-1,2,3,4-tetrahydro-carbazole afforded N,N-dimethyl-3-(3-indolyl)propionamide and N, N-dimethyl-2-(6-methyl-1,2,3,4-tetrahydrocarbazol-1-yl)acetamide, respectively. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 314–318, February, 2007.     

Binding energies of metal monocations to Β-lactones and Β-lactams. A theoretical study of cyclization effects

Ab initio calculations have been performed to study the association of-propiolactam and-propiolactone and their aliphatic analoguesN-methyl acetamide and methyl acetate with different metal monocations: Li⁺, Na⁺, Mg⁺, and Al⁺, in an effort to investigate cyclization effects on the gas-phase basicities of amides and esters, when the reference acid is not a proton. Similarly to what was found for protonation,N-methyl acetamide and-propiolactam are more basic than methyl acetate and-propiolactone, when the reference acids are the aforementioned metal monocations. However, cyclization effects on the corresponding binding energies for both kind of compounds do not parallel those observed for protonation energies, and-lactone is as basic as methyl acetate when the reference acid is Li⁺ and slightly more basic than methyl acetate when the attaching ion is Na⁺. This implies that when the interactions of the bases with the reference acids are essentially electrostatic the reactivity patterns change with respect to those observed when the interactions are essentially covalent.     

p-t-Butylcalix[4]arene tetra-acetamide: a new strong receptor for alkali cations [1]

From the reaction ofp-t-butylcalix[4]arene with -chloro-N,N-diethyl acetamide a new lipophilic ether-amide ligand (2) has been obtained in high yield. Solution studies show (2) to be a very strong cation receptor for alkali cations, especially sodium and potassium. The X-ray crystal structure determination of the free ligand (2) and two potassium complexes (KI and KSCN) shows the calix[4]arene in a fixed cone structure and the cation completely encapsulated in a polar cavity of eight oxygen atoms. Supplementary Data relating to this article are deposited with the British Library as supplementary publication No. SUP 82059 (57 pages).Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986.     

Freezing temperatures of aqueous solutions of methyl formate and ethyl acetate with a variety of nonelectrolytes. Gibbs energy of interaction of the ester group with other functional groups

Freezing temperatures of dilute aqueous solutions of ethyl acetate and mixtures with myo-inositol, D-mannitol, formamide, 1,3,5-trioxane, 1,4-dioxane, acetamide, hexamethylenetetramine, and methyl formate have been measured. In addition, freezing temperatures of dilute aqueous solutions of methyl formate and mixtures with the above solutes have been measured. From these data, the pairwise molecular Gibbs energies of interaction between the molecules were calculated. Using the additivity principle, the pairwise functional group Gibbs energies of interaction were calculated for ester group interactions with a variety of other functional groups.     

[Eu（Bipy）2]Cl3和[Tb（Bipy）2]Cl3在有机功能化剥层水滑石表面上的组装及光致发光性质

以乙酰基丙氨基三乙氧基硅烷对剥层镁铝水滑石进行了表面硅烷化修饰,得到了表面硅烷化修饰的剥层水滑石复合材料.然后在该复合材料表面进行了[Eu(Bipy)2]3+和[Tb(Bipy)2]3+分子组装,得到了剥层水滑石复合稀土发光体.组装体的紫外激发发射光谱表明,稀土配合物被组装到经硅烷化试剂修饰的剥层水滑石表面后,其电偶极跃迁较原配合物有很大提高,热稳定性也有提高.从主客体材料相互作用角度对稀土配合物电偶极跃迁的提高进行了解释.     

Physico-chemical properties of Chitosan films

Chitosan films obtained by dry phase inversion were prepared from an aqueous solution of chitosan in acetic acid. The films, of thickness less than 20 μm, were transparent, very flexible and had smooth surfaces. Increasing the film thickness induced an increase of the internal tensions and the consequent formation of a rough surface. Structural investigations by X-ray diffraction and Fourier transform IR analysis, showed that the chitosan films, as prepared, are amorphous. Further annealing to evaporate acetic acid and water traces, changed the amorphous phase into a more ordered phase, characterized by diffraction peaks at 2θ values of 9, 17, 20 and 23 degrees. Thermal investigations by TG, DTG, and DTA revealed that the decomposition of the chitosan films as prepared proceeds in two stages, starting from 180°C and 540°C.