- Measurement of the Dissociation of EuII-Containing Cryptates Using Murexide
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The dissociation rates of five EuII-containing cryptates in water were measured using UV-visible spectroscopy and murexide at pH 6.5, 7, 7.5, 8, and 9. Murexide was used as a coordinating dye for EuII. The results for a known cryptate were within experimental error of the value obtained using other methods and enabled the measurement of other cryptates. This validation of the use of murexide to study the dissociation of EuII-containing cryptates enables its use with other complexes of EuII
- Lenora, Chamika U.,Staples, Richard J.,Allen, Matthew J.
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- FORMATION AND USES OF EUROPIUM
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An MRI contrast composition includes a liposome and a europium metal complex disposed within the liposome. The europium metal complex includes a europium metal ion and a multi-dentate ligand selected from the group consisting of cryptands and thiacryptands and one or more counter-ions that balances a charge of the europium metal ion and the multi-dentate ligand, the europium metal ion being switchable between a 2+ and 3+ oxidation state. The contrast composition advantageously provides an oxidation-responsive dual-mode contrast agent because it would enhance either T1-weighted images or CEST images depending on the oxidation state of Eu.
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Paragraph 0073
(2014/10/18)
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- KI-catalysed synthesis of 4-methylcatechol dimethylacetate and fragrant compound Calone 1951
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Synthesis of the fragrant compound Calone 1951 from 4-methyl catechol and methyl bromoacetate entails three successive reactions: the Williamson reaction, Dieckmann condensation, and hydrolysis-decarboxylation reaction. In this paper, the synthesis of 4-methylcatechol dimethylacetate (MCDA) via the Williamson reaction by adding KI as catalyst was investigated. It was found that the addition of an appropriate amount of KI can significantly increase the product yield due to generation of methyl iodoacetate via the reaction between KI and methyl bromoacetate. The synthesised MCDA as well as Calone 1951 were first characterised by melting points, HPLC, IR, and NMR analyses. Next, the effect of the key operating factors on MCDA synthesis by the Williamson reaction was investigated and the optimum operating conditions were obtained via a group of orthogonal experiments. The verification experiments demonstrated that, under the optimum operating conditions, the MCDA yield could be increased from 78.5 % to 95.4 % by the addition of an appropriate amount of KI; the corresponding yield of Calone 1951 increased to 68 %.
- Zhang, Ya-Zheng,Yang, Qian,Huang, Shao-Jian,Luo, Zi-Ping,Li, Wen-Ping,Dong, Li-Chun
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p. 586 - 593
(2013/07/26)
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- Synthesis of benzodioxepinone analogues via a novel synthetic route with qualitative olfactory evaluation
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Marine odorants represent a minor yet diverse class of substances within the fragrance industry, of which 7-methyl-2H-1,5-benzodioxepin-3(4H)-one (1) is commercially known as Calone 1951, a synthetic first in the area of marine-fragrance chemistry. To determine the extent to which the characteristic marine odor of Calone 1951 corresponds to the substitution at the benzo portion of the molecule, a variety of aromatic substituents were incorporated into the benzodioxepinone structure (Scheme 1, Table 3). In light of the difficulty experienced in applying patented literature to deriving the analogues 12-18, particularly those with electron-withdrawing substituents, an alternative synthetic scheme was implemented for the construction of all analogues in favorable yields (Scheme 4, Table 3). Formation of the hydroxy-protected dihalo alkylating agent 24 via epoxide cleavage of epichlorohydrin (Scheme 3) allowed etherification favoring dihalo displacement and subsequent intramolecular ring closure (-→26a-g). THP Deprotection followed by oxidation of the alcohols 27a-g to the ketones 12-18 provided a general pathway to the benzodioxepinone products. The influence of the substituent nature on odor activity revealed a diverse scope of olfactory character (Table 4).
- Drevermann, Britta,Lingham, Anthony R.,Huegel, Helmut M.,Marriott, Philip J.
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p. 1006 - 1027
(2008/02/04)
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- Microwave assisted synthesis of the fragrant compound Calone 1951
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Microwave irradiation has been utilised in a three-step synthetic route to the fragrant compound, 7-methyl-benzo[b][1,4]dioxepin-3-one, commercially known as Calone 1951. The use of a microwave reactor increases the simplicity and efficiency of the overall synthesis. Calone 1951, 7-methyl-benzo[b][1,4]dioxepin-3-one, possesses a strong marine, ozone note with floral nuances and is synthesised via a three-step procedure using microwave irradiation. High yields were obtained, and reaction times reduced to a few minutes, allowing for an efficient and inexpensive synthesis of Calone 1951.
- Drevermann, Britta,Lingham, Anthony,Hügel, Helmut,Marriott, Philip
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- The O-substitution pattern of the MoCl5-mediated oxidative aryl-aryl coupling reaction
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Different protective groups for the phenolic oxygen were investigated in the molybdenum pentachloride-mediated dehydrodimerization reaction. Cyclic acetals and ketals, triisopropylsilyl and alkoxycarbonylmethyl moieties are compatible with the strong acidic reaction conditions.
- Kramer, Beate,Fr?hlich, Roland,Bergander, Klaus,Waldvogel, Siegfried R.
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