- The influence of hydrogen-bond defects on the properties of ionic liquids
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Counterintuitive: The preformation of ion pairs can explain the low melting points of imidazolium-based ionic liquids (ILs) and the resulting expanded range of working temperatures. This quasi-ion-pair formation is possible for ILs having cations with only one interaction site leading to local and directional hydrogen bonds with the corresponding anion (see structure; O red, N blue, F green, S yellow). Copyright
- Peppel, Tim,Roth, Christian,Fumino, Koichi,Paschek, Dietmar,Koeckerling, Martin,Ludwig, Ralf
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- Solvent-freeN-Boc deprotection byex situgeneration of hydrogen chloride gas
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An efficient, scalable and sustainable method for the quantitative deprotection of thetert-butyl carbamate (N-Boc) protecting group is described, using down to near-stoichiometric amounts of hydrogen chloride gas in solvent-free conditions. We demonstrate theex situgeneration of hydrogen chloride gas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety ofN-Boc derivatives to obtain the hydrochloride salts in quantitative yields. The procedure obviates the need for any work-up or purification steps providing an uncomplicated green alternative to standard methods. Due to the solvent-free, anhydrous conditions, this method shows high tolerance towards acid sensitive functional groups and furnishes expanded functional group orthogonality.
- De Borggraeve, Wim M.,Gilles, Philippe,Van Mileghem, Seger,Verschueren, Rik H.
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supporting information
p. 5782 - 5787
(2021/07/12)
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- Novel room temperature ionic liquids and low melting mixtures based on imidazolium: Cheap ionic solvents for chemical and biological applications
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Novel protic ionic liquids (PILs) and low melting mixtures (LMMs) have been synthesized based on green components, cheap sources, the high purity, and easy way of preparation. PILs include [Im][For], [Im][Ace], [Im][Pro], [Im][But], and [Im][Pen]. LMMs include [ImCl][EG], [ImCl][Gly], [ImCl][PEG], [ImCl][ETA], and [ImCl][carbohydrate] + DMSO. These solvents contain imidazolium/imidazolium chloride as a cation/salt. NMR spectroscopy was used to analyze the structures of solvents. Melting points, and thermal stabilities were measured via thermal analyses. We were looking to synthesize new DESs with imidazolium chloride (ImCl); Due to lack of observation the melting points for mixtures of ImCl + hydrogen bond donors (HBDs), these mixtures were called low melting mixtures (LMMs) in this work. The mixtures of PILs/LMMs with molecular solvents showed good implications for homogenous and heterogenous systems which can be used for separation goals. Solubilities of carbohydrates, and some amino acids were tested in pure and mixed of ILs with molecular liquids. Adding DMSO to ILs/LMMs increased the dissolution of carbohydrates. As well, adding water to ILs had a remarkable effect for increasing the solubility of amino acids.
- Aryafard, Meysam,Minofar, Babak,Cséfalvay, Eva,Malinová, Lenka,?eha, David
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- Continuous flow solvent free organic synthesis involving solids (reactants/products) using a screw reactor
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Here we report for the first-time various organic transformations such as aldol condensation, oxidation, nucleophilic substitutions, protection, acylations and coupling reactions using a mechanochemical approach at a controlled temperature using a single synthesis platform. Almost minimal solvents or solvent-free conditions are used, making it a very efficient and clean synthesis of various products. A jacketed screw reactor when operated at different temperatures (0 °C to 160 °C) and over a range of rotation speeds for changing the residence time (15 s-300 s) helped to achieve maximum conversion. This approach is also extended to the synthesis using substrates having different substitutions, heterocycles and steric hindrance.
- Sharma, Brijesh M.,Atapalkar, Ranjit S.,Kulkarni, Amol A.
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supporting information
p. 5639 - 5646
(2019/10/22)
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- A Simple synthesis of sugar nucleoside diphosphates by chemical coupling in water
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Sugar nucleotides made easy: The new reagent ImIm , which is formed in-situ in water, is shown to activate nucleoside 5'-phosphates to their imidazolides, these can subsequently couple with sugar-1-phosphates; the whole procedure takes place in water. This truly simple method yields a crude product mixture that can be used directly as a source of donors for glycosyltransferase- mediated oligsaccharide synthesis. In the scheme, B stands for the nucleobases U, A, or G. Copyright
- Tanaka, Hidenori,Yoshimura, Yayoi,Jürgensen, Malene R.,Cuesta-Seijo, Jose A.,Hindsgaul, Ole
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p. 11531 - 11534
(2013/01/15)
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- Pairing heterocyclic cations with closo-dodecafluorododecaborate (2-): Synthesis of binary heterocyclium(1+) salts and a Ag4(heterocycle) 84+ salt of B12F122-
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Eight binary salts that pair triazolium(1+), imidazolium(1+), pyrimidinium(1+), or purinium(1+) cations with the icosahedral closo-dodecafluorododecaborate(2-) anion (B12F12 2-) were synthesized using open-air benchtop metathesis reactions in water or acetonitrile. The scale of the reactions varied from just milligrams to nearly one gram of the K2B12F12 starting material. Other reaction conditions, the scope of the reaction, and the solubilities for the new salts are discussed. Five [heterocyclium] 2[B12F12] salts, which were obtained in yields ranging from 84% to 99%, displayed significantly higher densities than the corresponding previously reported analogous [heterocyclium]2[B 12H12] and [heterocyclium][CB11H12] salts. A ninth high-density salt consisted of B12F12 2- paired with a complex Ag4(triazole)8 4+ cation. The structures of eight of the nine new compounds were determined by single-crystal X-ray diffraction analysis. The density of five [heterocyclium]2[B12F12] salts was found to increase approximately linearly as the distance between the five-membered-ring heterocyclium(1+) cation centroids decreased. This work demonstrates additional flexibility for the rational design of ionic structures with predictable properties, which will ultimately permit the tailoring of ingredient-response behavior.
- Belletire, John L.,Schneider, Stefan,Shackelford, Scott A.,Peryshkov, Dmitry V.,Strauss, Steven H.
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body text
p. 925 - 936
(2011/11/14)
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- Total synthesis of depsilairdin
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(Figure presented) The total synthesis of depsilairdin, a host-selective phytotoxin isolated from Leptosphaeria maculans (the causal agent of blackleg disease of oilseed Brassicas), has been achieved by N-terminal extension of a suitably protected derivative of the hitherto unknown amino acid (2S,3S,4R)-3,4-dihydroxy-3-methyl-proline (Dhmp) followed by esterification with lairdinol A. The latter esterification, complicated by the sterically hindered nature of the carboxyl group, was accomplished by a novel method involving reaction of the 1-hydroxybenzotriazole (HOBt) derived active ester with the bromomagnesium alkoxide of lairdinol A. Three depsilairdin analogues were also prepared by replacing the Dhmp residue with l-proline and cis- and trans-4-hydroxy-l-proline. Phytotoxicity assays showed that the analogues were nontoxic to both blackleg-susceptible (brown mustard) and -resistant (canola) plants, suggesting that the presence of the Dhmp residue in depsilairdin is important for its host-selective toxicity toward brown mustard.
- Ward, Dale E.,Pardeshi, Sandip G.
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supporting information; scheme or table
p. 5170 - 5177
(2010/09/16)
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- PROCESS FOR PRODUCING N,N'-CARBONYLDIIMIDAZOLE
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The present invention provides a process for producing N,N'-carbonyldiimidazole, comprising: reacting phosgene, diphosgene, or triphosgene with imidazole in an inert solvent to produce N,N'-carbonyldiimidazole; to imidazole hydrochloride yielded as a by-product in the above step, adding a gaseous or liquid basic compound represented by the below-shown general formula (1) in an inert solvent to conduct neutralization reaction; and circulating the imidazole thus generated to use it as a starting material for N,N'-carbonyldiimidazole production. In the general formula (1), R 1 , R 2 , and R 3 each independently represents a hydrogen atom, a methyl group, or an ethyl group. The CDI produced by the production process of the invention is a compound useful in the fields of synthesis of pharmaceutical agents, synthesis of agricultural chemicals, peptide synthesis, and the like, e.g., intermolecular condensation reactions, intramolecular condensation reactions for synthesizing N-carboxylic anhydrides, production of activated esters, and the like. The compound is especially suitable for use in applications where colorlessness is required.
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Page/Page column 5
(2008/06/13)
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- Process for preparing N,N'-carbonyldiazoles
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A process is provided for preparing N,N′-carbonyldiazoles by reacting azoles with phosgene in halogenated aliphatic hydrocarbon solvents, the entirety of the azole for reaction being introduced in the solvent, followed by the addition of phosgene.
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Page/Page column 4
(2008/06/13)
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- Process for the production of N,N-carbonyl diimidazole
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A high purity N,N-Carbonyl diimidazole (I) is obtained by the reaction of Imidazole, general formula-II, and bis (trichloromethyl) carbonate. Synthesis of N,N-Carbonyl diimidazole (I) is described:
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- IMIDAZOLYLPHENOL COMPOUNDS, PHARMACEUTICAL COMPOSITIONS CONTAINING THEM, AND PROCESSES FOR PREPARING SUCH COMPOUNDS AND COMPOSITIONS
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3-and 4-(1H-imidazol-1-yl)phenol compounds corresponding to the formula I in which R1 represents NH2 or CH3, R2 represents H or CH3, X represents O or S, Y represents H, OH or OCH3, and Z represents ?CH=CH?, O or S, or their salts, which exhibit 5-lipoxyg
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- 2,2'-bi-1H-imidazoles
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This invention relates to novel derivatives of 2,2'-bi-1H-imidazoles, to the processes and intermediates used in their preparation, to their ability to exert the pharmacologic effects of lowering high blood pressure and of increasing heart contractile force and to their use as chemotherpauetic agents useful in treating cardiac insufficiency and hypertension.
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- Selective monoacylation of substituted hydrazines
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Mono-acylated hydrazines are prepared in high yield by reaction of a hydrazine salt with an azole derivative of acyl halide in the presence of a strong base. Useful hydrazine salts include those of the formula RNHNH2 *HX, where R is alkyl, aryl
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- CERTAIN IMIDAZOLE COMPOUNDS AS TRANSGLUTAMINASE INHIBITORS
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A method for inhibiting transglutaminase activity, especially Factor XIIIa activity with certain imidazole compounds is described. The imidazole compounds are those selected from(A) a imidazole having the formula STR1 or its acid addition salt, and STR2 wherein: R is hydrogen or lower alkyl;R 1 is lower alkyl;R. sup.2 and R 3 are independently hydrogen or lower alkyl;R. sup.4 is lower alkyl; andX is the negative radical of a pharmaceutically acceptable salt.Also described are compositions suitable for use in inhibiting transglutaminase activity.
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- INVESTIGATION OF N-ACYLIMIDAZOLIUM SALTS IN LOW-POLARITY MEDIA BY PMR
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A new model system is proposed for the investigation of the intermediate products from nucleophilic catalysis on the basis of 1-dimethylcarbamoyl-3-methylimidazolium chloride in low-polarity proton-inert media by the NMR method.It was shown that the structural parameter most sensitive to change in the nature of the acyl part, the anion of the salt, and the formation of an H bond is the chemical shift of the hydrogen atom at position 2 of the imidazolium ion.
- Lapshin, S. A.,Chervinskii, A. Yu.,Litvinenko, L. M.,Dadali, V. A.,Kapkan, L. M.,Vdovichenko, A. N.
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p. 321 - 326
(2007/10/02)
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- Aminopropanol substituted indole compounds and compositions for the treatment of cardiac and circulatory diseases
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New aminopropanol compounds of the formula STR1 wherein R is lower alkyl, cycloalkyl or alkylthioalkyl, R1 is hydrogen or lower alkyl, hydroxyalkyl, pivaloyloxyalkyl, alkoxyalkyl, alkoxycarbonyl, carboxyl or --CONR3 R4, in which R3 and R4 which can be the same or different, represent hydrogen or lower alkyl, and R2 is lower alkyl, hydroxyalkyl, alkoxyalkyl or pivaloyloxyalkyl or, when R is alkylthioalkyl or R1 is pivaloyloxyalkyl, R2 can also be hydrogen and the pharmacologically acceptable salts thereof; are outstandingly effective in the treatment or prophylaxis of cardiac and circulatory diseases.
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