- Facile synthesis of highly functionalized stable ketenimines by a three-component reaction of alkyl isocyanides, dialkyl acetylenedicarboxylates and ethyl carbazones
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The reactive intermediate generated by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates was trapped by ethyl carbazones to produce stable ketenimine derivatives in good yield. The reaction is characterized by mild conditions, high sel
- Anary-Abbasinejad, Mohammad,Anaraki-Ardakani, Hossein,Ghanea, Fatemeh
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body text
p. 397 - 400
(2010/05/01)
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- Controlled release of volatile aldehydes and ketones from dynamic mixtures generated by reversible hydrazone formation
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Delivery systems generated by reversible hydrazone formation from hydrazine derivatives (see Fig. 1) and carbonyl compounds in H2O efficiently increase the long-lastingness of volatile aldehydes and ketones (R 1R2C=O) in various perfumery applications. The hydrazones are usually obtained in an (E) configuration at the imine double bond (NHN=C) and, in the case of aliphatic acylhydrazones R′CO-NH-N=CR 1R2 (R′ = alkyl), as syn and anti conformers with respect to the amide bond (CO-NHN). An average free-energy barrier of ca. 78kJ/mol was determined for the amide-bond rotation by variable-temperature 1H-NMR measurements (Fig. 2). In the presence of H2O, the hydrazone formation is entirely reversible, reaching an equilibrium composed of the hydrazine derivative, the carbonyl compound, and the corresponding hydrazone. Kinetic measurements carried out by UV/VIS spectroscopy showed that the same equilibrium was reached for the formation and hydrolysis of the hydrazone. Rate constants are strongly pH-dependent and increase with decreasing pH (Table 1). The influence of the hydrazine structure on the rate constants is less pronounced than the pH effect, and the presence of surfactants reduces the rate of equilibration (Tables 1 and 3). The full reversibility of the hydrazone formation allows to prepare dynamic mixtures by simple addition of a hydrazine derivative to several carbonyl compounds. Dynamic headspace analysis on dry cotton showed that the presence of a hydrazine derivative significantly increased the headspace concentrations of the different carbonyl compounds as compared to the reference sample without hydrazine (Table 4). The release of the volatiles was found to be efficient for fragrances with high vapor pressures and low H2O solubility. Furthermore, a special long-lasting effect was obtained for the release of ketones. The simplicity of generating dynamic mixtures combined with the high efficiency for the release of volatiles makes these systems particularly interesting for practical applications and will certainly influence the development of delivery systems in other areas such as the pharmaceutical or agrochemical industry.
- Levrand, Barbara,Fieber, Wolfgang,Lehn, Jean-Marie,Herrmann, Andreas
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p. 2281 - 2314
(2008/03/29)
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- USE OF DYNAMIC MIXTURES FOR A CONTROLLED RELEASE OF FRAGRANCES
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The present invention relates to a delivery system in the form of a dynamic mixture obtained by reacting together, in the presence of water, at least one hydrazine derivative with at least one perfuming, flavoring, insect repellent or attractant, bactericide and/or fungicide aldehyde or ketone. The invention's mixture is capable of releasing in a controlled and prolonged manner said aldehyde or ketone in the surrounding environment. Furthermore, the present invention concerns also the use of said dynamic mixtures as perfuming ingredients as well as the perfuming compositions or perfumed articles comprising the invention's mixtures.
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Page/Page column 26
(2008/06/13)
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- X=Y-ZH SYSTEMS AS POTENTIAL 1,3-DIPOLES. PART 20. DECARBOXYLATION OF α-IMINO ACIDS. MECHANIZM AND APPLICATIONS TO THIOAMIDE SYNTHESIS
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α-Imino acids, prepared from α-keto acids and primary amines, undergo facile decarboxylation to the corresponding imines on heating at =80 deg C in benzene or methylene chloride.Decarboxylation proceeds via a 1,2-ylide which can be trapped by sulphur to give the corresponding secondary thioamides in good yield. 1,2-Ylides from secondary amines and α-keto acids can be generated in situ and trapped with sulphur to give tertiary thioamides in excellent yield.
- Aly, Moustafa F.,Grigg, Ronald
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p. 7271 - 7282
(2007/10/02)
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- ORGANISCHE PHOSPHORVERBINDUNGEN 84. HERSTELLUNG, EIGENSCHAFTEN UND BIOLOGISCHE WIRKUNG VON HYDRAZINOMETHYL-PHOSPHON- UND -PHOSPHINSAEUREN UND DERIVATEN
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The synthesis and the chemical, physical, spectral and biological properties of hydrazinomethyl-phosphonic- and -phosphinic acids and derivatives, i.e. hydrazino-N-alkoxycarbonyl-N'-alkylene-O,O-dialkoxyphosphonates, 2, -phosphinates, 3, hydrazinomethyl-O
- Diel, Peter J.,Maier, Ludwig
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- 1,3,4-Oxadiazolin-2-ones from Carbo-t-butoxyhydrazones
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5-Substituted-1,3,4-oxadiazolin-2-ones 2 were synthesized by the oxidation of carbo-t-butoxyhydrazones 1 of aromatic aldehydes with lead tetraacetate or, preferably, iodosobenzene diacetate.In some instances 5-acetoxy-1,3,4-oxadiazoles 3 were obtained along with 2.The oxidation of carboethoxyhydrazones 4 gave 2-ethoxy-1,3,4-oxadiazoles 5.
- Baumgarten, Henry E.,Hwang, Deng-Ruey,Rao, T. N.
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p. 945 - 949
(2007/10/02)
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- ELECTRON DEFICIENT HETEROAROMATIC AMMONIOAMIDATES, XIX. N-(3-QUINAZOLINIO)AMIDATES, VII. THE PHOTOCHEMISTRY OF N-(3-QUINAZOLINIO)AMIDATES IN THE PRESENCE OF AMINES AND OF ACETAMIDE
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Irradiation by Pyrex-filtered light of the quinazolinioamidates 1c-1f and of the dimers 2a and 2b in butylamine, of compound 2b in benzylamine and morpholine, and in the presence of acetamide in dioxane or dichloromethane, as well as of the adducts 5a and 5b in dichloromethane leads to complex mixtures of Type 6-16 products.While the compounds 6-9 are the products of Type II cleavage processes of the Type 3-5 adducts, the parent quinazolines 12 are formed from the amidates 1 themselves, amides 14 being the co-products in both cases.Compound 10a is formed by deacetylation of 9a during work-up, while compound 11b is a secondary photosubstitution product of 12b by the solvent dioxane.At least part of the compounds 13, 15 and 16 is the result of dark reactions.
- Barta-Szalai, G.,Fetter, J.,Lempert, K.,Moller, J.
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p. 253 - 266
(2007/10/02)
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